Updated DB_Helper by adding firebase methods.

This commit is contained in:
Batuhan Berk Başoğlu 2020-10-05 16:53:40 -04:00
parent 485cc3bbba
commit c82121d036
1810 changed files with 537281 additions and 1 deletions

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# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""RSA module
Module for calculating large primes, and RSA encryption, decryption, signing
and verification. Includes generating public and private keys.
WARNING: this implementation does not use compression of the cleartext input to
prevent repetitions, or other common security improvements. Use with care.
"""
from rsa.key import newkeys, PrivateKey, PublicKey
from rsa.pkcs1 import encrypt, decrypt, sign, verify, DecryptionError, \
VerificationError, find_signature_hash, sign_hash, compute_hash
__author__ = "Sybren Stuvel, Barry Mead and Yesudeep Mangalapilly"
__date__ = '2020-06-12'
__version__ = '4.6'
# Do doctest if we're run directly
if __name__ == "__main__":
import doctest
doctest.testmod()
__all__ = ["newkeys", "encrypt", "decrypt", "sign", "verify", 'PublicKey',
'PrivateKey', 'DecryptionError', 'VerificationError',
'find_signature_hash', 'compute_hash', 'sign_hash']

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# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Python compatibility wrappers."""
from struct import pack
def byte(num: int) -> bytes:
"""
Converts a number between 0 and 255 (both inclusive) to a base-256 (byte)
representation.
:param num:
An unsigned integer between 0 and 255 (both inclusive).
:returns:
A single byte.
"""
return pack("B", num)
def xor_bytes(b1: bytes, b2: bytes) -> bytes:
"""
Returns the bitwise XOR result between two bytes objects, b1 ^ b2.
Bitwise XOR operation is commutative, so order of parameters doesn't
generate different results. If parameters have different length, extra
length of the largest one is ignored.
:param b1:
First bytes object.
:param b2:
Second bytes object.
:returns:
Bytes object, result of XOR operation.
"""
return bytes(x ^ y for x, y in zip(b1, b2))

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# -*- coding: utf-8 -*-
#
# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Deprecated version of the RSA module
.. deprecated:: 2.0
This submodule is deprecated and will be completely removed as of version 4.0.
Module for calculating large primes, and RSA encryption, decryption,
signing and verification. Includes generating public and private keys.
WARNING: this code implements the mathematics of RSA. It is not suitable for
real-world secure cryptography purposes. It has not been reviewed by a security
expert. It does not include padding of data. There are many ways in which the
output of this module, when used without any modification, can be sucessfully
attacked.
"""
__author__ = "Sybren Stuvel, Marloes de Boer and Ivo Tamboer"
__date__ = "2010-02-05"
__version__ = '1.3.3'
# NOTE: Python's modulo can return negative numbers. We compensate for
# this behaviour using the abs() function
try:
import cPickle as pickle
except ImportError:
import pickle
from pickle import dumps, loads
import base64
import math
import os
import random
import sys
import types
import zlib
from rsa._compat import byte
# Display a warning that this insecure version is imported.
import warnings
warnings.warn('Insecure version of the RSA module is imported as %s, be careful'
% __name__)
warnings.warn('This submodule is deprecated and will be completely removed as of version 4.0.',
DeprecationWarning)
def gcd(p, q):
"""Returns the greatest common divisor of p and q
>>> gcd(42, 6)
6
"""
if p<q: return gcd(q, p)
if q == 0: return p
return gcd(q, abs(p%q))
def bytes2int(bytes):
"""Converts a list of bytes or a string to an integer
"""
if not (type(bytes) is types.ListType or type(bytes) is types.StringType):
raise TypeError("You must pass a string or a list")
# Convert byte stream to integer
integer = 0
for byte in bytes:
integer *= 256
if type(byte) is types.StringType: byte = ord(byte)
integer += byte
return integer
def int2bytes(number):
"""Converts a number to a string of bytes
"""
if not (type(number) is types.LongType or type(number) is types.IntType):
raise TypeError("You must pass a long or an int")
string = ""
while number > 0:
string = "%s%s" % (byte(number & 0xFF), string)
number /= 256
return string
def fast_exponentiation(a, p, n):
"""Calculates r = a^p mod n
"""
result = a % n
remainders = []
while p != 1:
remainders.append(p & 1)
p = p >> 1
while remainders:
rem = remainders.pop()
result = ((a ** rem) * result ** 2) % n
return result
def read_random_int(nbits):
"""Reads a random integer of approximately nbits bits rounded up
to whole bytes"""
nbytes = ceil(nbits/8.)
randomdata = os.urandom(nbytes)
return bytes2int(randomdata)
def ceil(x):
"""ceil(x) -> int(math.ceil(x))"""
return int(math.ceil(x))
def randint(minvalue, maxvalue):
"""Returns a random integer x with minvalue <= x <= maxvalue"""
# Safety - get a lot of random data even if the range is fairly
# small
min_nbits = 32
# The range of the random numbers we need to generate
range = maxvalue - minvalue
# Which is this number of bytes
rangebytes = ceil(math.log(range, 2) / 8.)
# Convert to bits, but make sure it's always at least min_nbits*2
rangebits = max(rangebytes * 8, min_nbits * 2)
# Take a random number of bits between min_nbits and rangebits
nbits = random.randint(min_nbits, rangebits)
return (read_random_int(nbits) % range) + minvalue
def fermat_little_theorem(p):
"""Returns 1 if p may be prime, and something else if p definitely
is not prime"""
a = randint(1, p-1)
return fast_exponentiation(a, p-1, p)
def jacobi(a, b):
"""Calculates the value of the Jacobi symbol (a/b)
"""
if a % b == 0:
return 0
result = 1
while a > 1:
if a & 1:
if ((a-1)*(b-1) >> 2) & 1:
result = -result
b, a = a, b % a
else:
if ((b ** 2 - 1) >> 3) & 1:
result = -result
a = a >> 1
return result
def jacobi_witness(x, n):
"""Returns False if n is an Euler pseudo-prime with base x, and
True otherwise.
"""
j = jacobi(x, n) % n
f = fast_exponentiation(x, (n-1)/2, n)
if j == f: return False
return True
def randomized_primality_testing(n, k):
"""Calculates whether n is composite (which is always correct) or
prime (which is incorrect with error probability 2**-k)
Returns False if the number if composite, and True if it's
probably prime.
"""
q = 0.5 # Property of the jacobi_witness function
# t = int(math.ceil(k / math.log(1/q, 2)))
t = ceil(k / math.log(1/q, 2))
for i in range(t+1):
x = randint(1, n-1)
if jacobi_witness(x, n): return False
return True
def is_prime(number):
"""Returns True if the number is prime, and False otherwise.
"""
"""
if not fermat_little_theorem(number) == 1:
# Not prime, according to Fermat's little theorem
return False
"""
if randomized_primality_testing(number, 5):
# Prime, according to Jacobi
return True
# Not prime
return False
def getprime(nbits):
"""Returns a prime number of max. 'math.ceil(nbits/8)*8' bits. In
other words: nbits is rounded up to whole bytes.
"""
nbytes = int(math.ceil(nbits/8.))
while True:
integer = read_random_int(nbits)
# Make sure it's odd
integer |= 1
# Test for primeness
if is_prime(integer): break
# Retry if not prime
return integer
def are_relatively_prime(a, b):
"""Returns True if a and b are relatively prime, and False if they
are not.
"""
d = gcd(a, b)
return (d == 1)
def find_p_q(nbits):
"""Returns a tuple of two different primes of nbits bits"""
p = getprime(nbits)
while True:
q = getprime(nbits)
if not q == p: break
return (p, q)
def extended_euclid_gcd(a, b):
"""Returns a tuple (d, i, j) such that d = gcd(a, b) = ia + jb
"""
if b == 0:
return (a, 1, 0)
q = abs(a % b)
r = long(a / b)
(d, k, l) = extended_euclid_gcd(b, q)
return (d, l, k - l*r)
# Main function: calculate encryption and decryption keys
def calculate_keys(p, q, nbits):
"""Calculates an encryption and a decryption key for p and q, and
returns them as a tuple (e, d)"""
n = p * q
phi_n = (p-1) * (q-1)
while True:
# Make sure e has enough bits so we ensure "wrapping" through
# modulo n
e = getprime(max(8, nbits/2))
if are_relatively_prime(e, n) and are_relatively_prime(e, phi_n): break
(d, i, j) = extended_euclid_gcd(e, phi_n)
if not d == 1:
raise Exception("e (%d) and phi_n (%d) are not relatively prime" % (e, phi_n))
if not (e * i) % phi_n == 1:
raise Exception("e (%d) and i (%d) are not mult. inv. modulo phi_n (%d)" % (e, i, phi_n))
return (e, i)
def gen_keys(nbits):
"""Generate RSA keys of nbits bits. Returns (p, q, e, d).
Note: this can take a long time, depending on the key size.
"""
while True:
(p, q) = find_p_q(nbits)
(e, d) = calculate_keys(p, q, nbits)
# For some reason, d is sometimes negative. We don't know how
# to fix it (yet), so we keep trying until everything is shiny
if d > 0: break
return (p, q, e, d)
def gen_pubpriv_keys(nbits):
"""Generates public and private keys, and returns them as (pub,
priv).
The public key consists of a dict {e: ..., , n: ....). The private
key consists of a dict {d: ...., p: ...., q: ....).
"""
(p, q, e, d) = gen_keys(nbits)
return ( {'e': e, 'n': p*q}, {'d': d, 'p': p, 'q': q} )
def encrypt_int(message, ekey, n):
"""Encrypts a message using encryption key 'ekey', working modulo
n"""
if type(message) is types.IntType:
return encrypt_int(long(message), ekey, n)
if not type(message) is types.LongType:
raise TypeError("You must pass a long or an int")
if message > 0 and \
math.floor(math.log(message, 2)) > math.floor(math.log(n, 2)):
raise OverflowError("The message is too long")
return fast_exponentiation(message, ekey, n)
def decrypt_int(cyphertext, dkey, n):
"""Decrypts a cypher text using the decryption key 'dkey', working
modulo n"""
return encrypt_int(cyphertext, dkey, n)
def sign_int(message, dkey, n):
"""Signs 'message' using key 'dkey', working modulo n"""
return decrypt_int(message, dkey, n)
def verify_int(signed, ekey, n):
"""verifies 'signed' using key 'ekey', working modulo n"""
return encrypt_int(signed, ekey, n)
def picklechops(chops):
"""Pickles and base64encodes it's argument chops"""
value = zlib.compress(dumps(chops))
encoded = base64.encodestring(value)
return encoded.strip()
def unpicklechops(string):
"""base64decodes and unpickes it's argument string into chops"""
return loads(zlib.decompress(base64.decodestring(string)))
def chopstring(message, key, n, funcref):
"""Splits 'message' into chops that are at most as long as n,
converts these into integers, and calls funcref(integer, key, n)
for each chop.
Used by 'encrypt' and 'sign'.
"""
msglen = len(message)
mbits = msglen * 8
nbits = int(math.floor(math.log(n, 2)))
nbytes = nbits / 8
blocks = msglen / nbytes
if msglen % nbytes > 0:
blocks += 1
cypher = []
for bindex in range(blocks):
offset = bindex * nbytes
block = message[offset:offset+nbytes]
value = bytes2int(block)
cypher.append(funcref(value, key, n))
return picklechops(cypher)
def gluechops(chops, key, n, funcref):
"""Glues chops back together into a string. calls
funcref(integer, key, n) for each chop.
Used by 'decrypt' and 'verify'.
"""
message = ""
chops = unpicklechops(chops)
for cpart in chops:
mpart = funcref(cpart, key, n)
message += int2bytes(mpart)
return message
def encrypt(message, key):
"""Encrypts a string 'message' with the public key 'key'"""
return chopstring(message, key['e'], key['n'], encrypt_int)
def sign(message, key):
"""Signs a string 'message' with the private key 'key'"""
return chopstring(message, key['d'], key['p']*key['q'], decrypt_int)
def decrypt(cypher, key):
"""Decrypts a cypher with the private key 'key'"""
return gluechops(cypher, key['d'], key['p']*key['q'], decrypt_int)
def verify(cypher, key):
"""Verifies a cypher with the public key 'key'"""
return gluechops(cypher, key['e'], key['n'], encrypt_int)
# Do doctest if we're not imported
if __name__ == "__main__":
import doctest
doctest.testmod()
__all__ = ["gen_pubpriv_keys", "encrypt", "decrypt", "sign", "verify"]

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# -*- coding: utf-8 -*-
#
# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Deprecated version of the RSA module
.. deprecated:: 3.0
This submodule is deprecated and will be completely removed as of version 4.0.
"""
__author__ = "Sybren Stuvel, Marloes de Boer, Ivo Tamboer, and Barry Mead"
__date__ = "2010-02-08"
__version__ = '2.0'
import math
import os
import random
import sys
import types
from rsa._compat import byte
# Display a warning that this insecure version is imported.
import warnings
warnings.warn('Insecure version of the RSA module is imported as %s' % __name__)
warnings.warn('This submodule is deprecated and will be completely removed as of version 4.0.',
DeprecationWarning)
def bit_size(number):
"""Returns the number of bits required to hold a specific long number"""
return int(math.ceil(math.log(number,2)))
def gcd(p, q):
"""Returns the greatest common divisor of p and q
>>> gcd(48, 180)
12
"""
# Iterateive Version is faster and uses much less stack space
while q != 0:
if p < q: (p,q) = (q,p)
(p,q) = (q, p % q)
return p
def bytes2int(bytes):
r"""Converts a list of bytes or a string to an integer
"""
if not (type(bytes) is types.ListType or type(bytes) is types.StringType):
raise TypeError("You must pass a string or a list")
# Convert byte stream to integer
integer = 0
for byte in bytes:
integer *= 256
if type(byte) is types.StringType: byte = ord(byte)
integer += byte
return integer
def int2bytes(number):
"""
Converts a number to a string of bytes
"""
if not (type(number) is types.LongType or type(number) is types.IntType):
raise TypeError("You must pass a long or an int")
string = ""
while number > 0:
string = "%s%s" % (byte(number & 0xFF), string)
number /= 256
return string
def to64(number):
"""Converts a number in the range of 0 to 63 into base 64 digit
character in the range of '0'-'9', 'A'-'Z', 'a'-'z','-','_'.
"""
if not (type(number) is types.LongType or type(number) is types.IntType):
raise TypeError("You must pass a long or an int")
if 0 <= number <= 9: #00-09 translates to '0' - '9'
return byte(number + 48)
if 10 <= number <= 35:
return byte(number + 55) #10-35 translates to 'A' - 'Z'
if 36 <= number <= 61:
return byte(number + 61) #36-61 translates to 'a' - 'z'
if number == 62: # 62 translates to '-' (minus)
return byte(45)
if number == 63: # 63 translates to '_' (underscore)
return byte(95)
raise ValueError('Invalid Base64 value: %i' % number)
def from64(number):
"""Converts an ordinal character value in the range of
0-9,A-Z,a-z,-,_ to a number in the range of 0-63.
"""
if not (type(number) is types.LongType or type(number) is types.IntType):
raise TypeError("You must pass a long or an int")
if 48 <= number <= 57: #ord('0') - ord('9') translates to 0-9
return(number - 48)
if 65 <= number <= 90: #ord('A') - ord('Z') translates to 10-35
return(number - 55)
if 97 <= number <= 122: #ord('a') - ord('z') translates to 36-61
return(number - 61)
if number == 45: #ord('-') translates to 62
return(62)
if number == 95: #ord('_') translates to 63
return(63)
raise ValueError('Invalid Base64 value: %i' % number)
def int2str64(number):
"""Converts a number to a string of base64 encoded characters in
the range of '0'-'9','A'-'Z,'a'-'z','-','_'.
"""
if not (type(number) is types.LongType or type(number) is types.IntType):
raise TypeError("You must pass a long or an int")
string = ""
while number > 0:
string = "%s%s" % (to64(number & 0x3F), string)
number /= 64
return string
def str642int(string):
"""Converts a base64 encoded string into an integer.
The chars of this string in in the range '0'-'9','A'-'Z','a'-'z','-','_'
"""
if not (type(string) is types.ListType or type(string) is types.StringType):
raise TypeError("You must pass a string or a list")
integer = 0
for byte in string:
integer *= 64
if type(byte) is types.StringType: byte = ord(byte)
integer += from64(byte)
return integer
def read_random_int(nbits):
"""Reads a random integer of approximately nbits bits rounded up
to whole bytes"""
nbytes = int(math.ceil(nbits/8.))
randomdata = os.urandom(nbytes)
return bytes2int(randomdata)
def randint(minvalue, maxvalue):
"""Returns a random integer x with minvalue <= x <= maxvalue"""
# Safety - get a lot of random data even if the range is fairly
# small
min_nbits = 32
# The range of the random numbers we need to generate
range = (maxvalue - minvalue) + 1
# Which is this number of bytes
rangebytes = ((bit_size(range) + 7) / 8)
# Convert to bits, but make sure it's always at least min_nbits*2
rangebits = max(rangebytes * 8, min_nbits * 2)
# Take a random number of bits between min_nbits and rangebits
nbits = random.randint(min_nbits, rangebits)
return (read_random_int(nbits) % range) + minvalue
def jacobi(a, b):
"""Calculates the value of the Jacobi symbol (a/b)
where both a and b are positive integers, and b is odd
"""
if a == 0: return 0
result = 1
while a > 1:
if a & 1:
if ((a-1)*(b-1) >> 2) & 1:
result = -result
a, b = b % a, a
else:
if (((b * b) - 1) >> 3) & 1:
result = -result
a >>= 1
if a == 0: return 0
return result
def jacobi_witness(x, n):
"""Returns False if n is an Euler pseudo-prime with base x, and
True otherwise.
"""
j = jacobi(x, n) % n
f = pow(x, (n-1)/2, n)
if j == f: return False
return True
def randomized_primality_testing(n, k):
"""Calculates whether n is composite (which is always correct) or
prime (which is incorrect with error probability 2**-k)
Returns False if the number is composite, and True if it's
probably prime.
"""
# 50% of Jacobi-witnesses can report compositness of non-prime numbers
for i in range(k):
x = randint(1, n-1)
if jacobi_witness(x, n): return False
return True
def is_prime(number):
"""Returns True if the number is prime, and False otherwise.
"""
if randomized_primality_testing(number, 6):
# Prime, according to Jacobi
return True
# Not prime
return False
def getprime(nbits):
"""Returns a prime number of max. 'math.ceil(nbits/8)*8' bits. In
other words: nbits is rounded up to whole bytes.
"""
while True:
integer = read_random_int(nbits)
# Make sure it's odd
integer |= 1
# Test for primeness
if is_prime(integer): break
# Retry if not prime
return integer
def are_relatively_prime(a, b):
"""Returns True if a and b are relatively prime, and False if they
are not.
>>> are_relatively_prime(2, 3)
1
>>> are_relatively_prime(2, 4)
0
"""
d = gcd(a, b)
return (d == 1)
def find_p_q(nbits):
"""Returns a tuple of two different primes of nbits bits"""
pbits = nbits + (nbits/16) #Make sure that p and q aren't too close
qbits = nbits - (nbits/16) #or the factoring programs can factor n
p = getprime(pbits)
while True:
q = getprime(qbits)
#Make sure p and q are different.
if not q == p: break
return (p, q)
def extended_gcd(a, b):
"""Returns a tuple (r, i, j) such that r = gcd(a, b) = ia + jb
"""
# r = gcd(a,b) i = multiplicitive inverse of a mod b
# or j = multiplicitive inverse of b mod a
# Neg return values for i or j are made positive mod b or a respectively
# Iterateive Version is faster and uses much less stack space
x = 0
y = 1
lx = 1
ly = 0
oa = a #Remember original a/b to remove
ob = b #negative values from return results
while b != 0:
q = long(a/b)
(a, b) = (b, a % b)
(x, lx) = ((lx - (q * x)),x)
(y, ly) = ((ly - (q * y)),y)
if (lx < 0): lx += ob #If neg wrap modulo orignal b
if (ly < 0): ly += oa #If neg wrap modulo orignal a
return (a, lx, ly) #Return only positive values
# Main function: calculate encryption and decryption keys
def calculate_keys(p, q, nbits):
"""Calculates an encryption and a decryption key for p and q, and
returns them as a tuple (e, d)"""
n = p * q
phi_n = (p-1) * (q-1)
while True:
# Make sure e has enough bits so we ensure "wrapping" through
# modulo n
e = max(65537,getprime(nbits/4))
if are_relatively_prime(e, n) and are_relatively_prime(e, phi_n): break
(d, i, j) = extended_gcd(e, phi_n)
if not d == 1:
raise Exception("e (%d) and phi_n (%d) are not relatively prime" % (e, phi_n))
if (i < 0):
raise Exception("New extended_gcd shouldn't return negative values")
if not (e * i) % phi_n == 1:
raise Exception("e (%d) and i (%d) are not mult. inv. modulo phi_n (%d)" % (e, i, phi_n))
return (e, i)
def gen_keys(nbits):
"""Generate RSA keys of nbits bits. Returns (p, q, e, d).
Note: this can take a long time, depending on the key size.
"""
(p, q) = find_p_q(nbits)
(e, d) = calculate_keys(p, q, nbits)
return (p, q, e, d)
def newkeys(nbits):
"""Generates public and private keys, and returns them as (pub,
priv).
The public key consists of a dict {e: ..., , n: ....). The private
key consists of a dict {d: ...., p: ...., q: ....).
"""
nbits = max(9,nbits) # Don't let nbits go below 9 bits
(p, q, e, d) = gen_keys(nbits)
return ( {'e': e, 'n': p*q}, {'d': d, 'p': p, 'q': q} )
def encrypt_int(message, ekey, n):
"""Encrypts a message using encryption key 'ekey', working modulo n"""
if type(message) is types.IntType:
message = long(message)
if not type(message) is types.LongType:
raise TypeError("You must pass a long or int")
if message < 0 or message > n:
raise OverflowError("The message is too long")
#Note: Bit exponents start at zero (bit counts start at 1) this is correct
safebit = bit_size(n) - 2 #compute safe bit (MSB - 1)
message += (1 << safebit) #add safebit to ensure folding
return pow(message, ekey, n)
def decrypt_int(cyphertext, dkey, n):
"""Decrypts a cypher text using the decryption key 'dkey', working
modulo n"""
message = pow(cyphertext, dkey, n)
safebit = bit_size(n) - 2 #compute safe bit (MSB - 1)
message -= (1 << safebit) #remove safebit before decode
return message
def encode64chops(chops):
"""base64encodes chops and combines them into a ',' delimited string"""
chips = [] #chips are character chops
for value in chops:
chips.append(int2str64(value))
#delimit chops with comma
encoded = ','.join(chips)
return encoded
def decode64chops(string):
"""base64decodes and makes a ',' delimited string into chops"""
chips = string.split(',') #split chops at commas
chops = []
for string in chips: #make char chops (chips) into chops
chops.append(str642int(string))
return chops
def chopstring(message, key, n, funcref):
"""Chops the 'message' into integers that fit into n,
leaving room for a safebit to be added to ensure that all
messages fold during exponentiation. The MSB of the number n
is not independant modulo n (setting it could cause overflow), so
use the next lower bit for the safebit. Therefore reserve 2-bits
in the number n for non-data bits. Calls specified encryption
function for each chop.
Used by 'encrypt' and 'sign'.
"""
msglen = len(message)
mbits = msglen * 8
#Set aside 2-bits so setting of safebit won't overflow modulo n.
nbits = bit_size(n) - 2 # leave room for safebit
nbytes = nbits / 8
blocks = msglen / nbytes
if msglen % nbytes > 0:
blocks += 1
cypher = []
for bindex in range(blocks):
offset = bindex * nbytes
block = message[offset:offset+nbytes]
value = bytes2int(block)
cypher.append(funcref(value, key, n))
return encode64chops(cypher) #Encode encrypted ints to base64 strings
def gluechops(string, key, n, funcref):
"""Glues chops back together into a string. calls
funcref(integer, key, n) for each chop.
Used by 'decrypt' and 'verify'.
"""
message = ""
chops = decode64chops(string) #Decode base64 strings into integer chops
for cpart in chops:
mpart = funcref(cpart, key, n) #Decrypt each chop
message += int2bytes(mpart) #Combine decrypted strings into a msg
return message
def encrypt(message, key):
"""Encrypts a string 'message' with the public key 'key'"""
if 'n' not in key:
raise Exception("You must use the public key with encrypt")
return chopstring(message, key['e'], key['n'], encrypt_int)
def sign(message, key):
"""Signs a string 'message' with the private key 'key'"""
if 'p' not in key:
raise Exception("You must use the private key with sign")
return chopstring(message, key['d'], key['p']*key['q'], encrypt_int)
def decrypt(cypher, key):
"""Decrypts a string 'cypher' with the private key 'key'"""
if 'p' not in key:
raise Exception("You must use the private key with decrypt")
return gluechops(cypher, key['d'], key['p']*key['q'], decrypt_int)
def verify(cypher, key):
"""Verifies a string 'cypher' with the public key 'key'"""
if 'n' not in key:
raise Exception("You must use the public key with verify")
return gluechops(cypher, key['e'], key['n'], decrypt_int)
# Do doctest if we're not imported
if __name__ == "__main__":
import doctest
doctest.testmod()
__all__ = ["newkeys", "encrypt", "decrypt", "sign", "verify"]

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# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""ASN.1 definitions.
Not all ASN.1-handling code use these definitions, but when it does, they should be here.
"""
from pyasn1.type import univ, namedtype, tag
class PubKeyHeader(univ.Sequence):
componentType = namedtype.NamedTypes(
namedtype.NamedType('oid', univ.ObjectIdentifier()),
namedtype.NamedType('parameters', univ.Null()),
)
class OpenSSLPubKey(univ.Sequence):
componentType = namedtype.NamedTypes(
namedtype.NamedType('header', PubKeyHeader()),
# This little hack (the implicit tag) allows us to get a Bit String as Octet String
namedtype.NamedType('key', univ.OctetString().subtype(
implicitTag=tag.Tag(tagClass=0, tagFormat=0, tagId=3))),
)
class AsnPubKey(univ.Sequence):
"""ASN.1 contents of DER encoded public key:
RSAPublicKey ::= SEQUENCE {
modulus INTEGER, -- n
publicExponent INTEGER, -- e
"""
componentType = namedtype.NamedTypes(
namedtype.NamedType('modulus', univ.Integer()),
namedtype.NamedType('publicExponent', univ.Integer()),
)

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# -*- coding: utf-8 -*-
#
# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Large file support
.. deprecated:: 3.4
The VARBLOCK format is NOT recommended for general use, has been deprecated since
Python-RSA 3.4, and will be removed in a future release. It's vulnerable to a
number of attacks:
1. decrypt/encrypt_bigfile() does not implement `Authenticated encryption`_ nor
uses MACs to verify messages before decrypting public key encrypted messages.
2. decrypt/encrypt_bigfile() does not use hybrid encryption (it uses plain RSA)
and has no method for chaining, so block reordering is possible.
See `issue #19 on Github`_ for more information.
.. _Authenticated encryption: https://en.wikipedia.org/wiki/Authenticated_encryption
.. _issue #19 on Github: https://github.com/sybrenstuvel/python-rsa/issues/13
This module contains functions to:
- break a file into smaller blocks, and encrypt them, and store the
encrypted blocks in another file.
- take such an encrypted files, decrypt its blocks, and reconstruct the
original file.
The encrypted file format is as follows, where || denotes byte concatenation:
FILE := VERSION || BLOCK || BLOCK ...
BLOCK := LENGTH || DATA
LENGTH := varint-encoded length of the subsequent data. Varint comes from
Google Protobuf, and encodes an integer into a variable number of bytes.
Each byte uses the 7 lowest bits to encode the value. The highest bit set
to 1 indicates the next byte is also part of the varint. The last byte will
have this bit set to 0.
This file format is called the VARBLOCK format, in line with the varint format
used to denote the block sizes.
"""
import warnings
from rsa import key, common, pkcs1, varblock
from rsa._compat import byte
def encrypt_bigfile(infile, outfile, pub_key):
"""Encrypts a file, writing it to 'outfile' in VARBLOCK format.
.. deprecated:: 3.4
This function was deprecated in Python-RSA version 3.4 due to security issues
in the VARBLOCK format. See the documentation_ for more information.
.. _documentation: https://stuvel.eu/python-rsa-doc/usage.html#working-with-big-files
:param infile: file-like object to read the cleartext from
:param outfile: file-like object to write the crypto in VARBLOCK format to
:param pub_key: :py:class:`rsa.PublicKey` to encrypt with
"""
warnings.warn("The 'rsa.bigfile.encrypt_bigfile' function was deprecated in Python-RSA version "
"3.4 due to security issues in the VARBLOCK format. See "
"https://stuvel.eu/python-rsa-doc/usage.html#working-with-big-files "
"for more information.",
DeprecationWarning, stacklevel=2)
if not isinstance(pub_key, key.PublicKey):
raise TypeError('Public key required, but got %r' % pub_key)
key_bytes = common.bit_size(pub_key.n) // 8
blocksize = key_bytes - 11 # keep space for PKCS#1 padding
# Write the version number to the VARBLOCK file
outfile.write(byte(varblock.VARBLOCK_VERSION))
# Encrypt and write each block
for block in varblock.yield_fixedblocks(infile, blocksize):
crypto = pkcs1.encrypt(block, pub_key)
varblock.write_varint(outfile, len(crypto))
outfile.write(crypto)
def decrypt_bigfile(infile, outfile, priv_key):
"""Decrypts an encrypted VARBLOCK file, writing it to 'outfile'
.. deprecated:: 3.4
This function was deprecated in Python-RSA version 3.4 due to security issues
in the VARBLOCK format. See the documentation_ for more information.
.. _documentation: https://stuvel.eu/python-rsa-doc/usage.html#working-with-big-files
:param infile: file-like object to read the crypto in VARBLOCK format from
:param outfile: file-like object to write the cleartext to
:param priv_key: :py:class:`rsa.PrivateKey` to decrypt with
"""
warnings.warn("The 'rsa.bigfile.decrypt_bigfile' function was deprecated in Python-RSA version "
"3.4 due to security issues in the VARBLOCK format. See "
"https://stuvel.eu/python-rsa-doc/usage.html#working-with-big-files "
"for more information.",
DeprecationWarning, stacklevel=2)
if not isinstance(priv_key, key.PrivateKey):
raise TypeError('Private key required, but got %r' % priv_key)
for block in varblock.yield_varblocks(infile):
cleartext = pkcs1.decrypt(block, priv_key)
outfile.write(cleartext)
__all__ = ['encrypt_bigfile', 'decrypt_bigfile']

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# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Commandline scripts.
These scripts are called by the executables defined in setup.py.
"""
import abc
import sys
import typing
import optparse
import rsa
import rsa.key
import rsa.pkcs1
HASH_METHODS = sorted(rsa.pkcs1.HASH_METHODS.keys())
Indexable = typing.Union[typing.Tuple, typing.List[str]]
def keygen() -> None:
"""Key generator."""
# Parse the CLI options
parser = optparse.OptionParser(usage='usage: %prog [options] keysize',
description='Generates a new RSA keypair of "keysize" bits.')
parser.add_option('--pubout', type='string',
help='Output filename for the public key. The public key is '
'not saved if this option is not present. You can use '
'pyrsa-priv2pub to create the public key file later.')
parser.add_option('-o', '--out', type='string',
help='Output filename for the private key. The key is '
'written to stdout if this option is not present.')
parser.add_option('--form',
help='key format of the private and public keys - default PEM',
choices=('PEM', 'DER'), default='PEM')
(cli, cli_args) = parser.parse_args(sys.argv[1:])
if len(cli_args) != 1:
parser.print_help()
raise SystemExit(1)
try:
keysize = int(cli_args[0])
except ValueError:
parser.print_help()
print('Not a valid number: %s' % cli_args[0], file=sys.stderr)
raise SystemExit(1)
print('Generating %i-bit key' % keysize, file=sys.stderr)
(pub_key, priv_key) = rsa.newkeys(keysize)
# Save public key
if cli.pubout:
print('Writing public key to %s' % cli.pubout, file=sys.stderr)
data = pub_key.save_pkcs1(format=cli.form)
with open(cli.pubout, 'wb') as outfile:
outfile.write(data)
# Save private key
data = priv_key.save_pkcs1(format=cli.form)
if cli.out:
print('Writing private key to %s' % cli.out, file=sys.stderr)
with open(cli.out, 'wb') as outfile:
outfile.write(data)
else:
print('Writing private key to stdout', file=sys.stderr)
sys.stdout.buffer.write(data)
class CryptoOperation(metaclass=abc.ABCMeta):
"""CLI callable that operates with input, output, and a key."""
keyname = 'public' # or 'private'
usage = 'usage: %%prog [options] %(keyname)s_key'
description = ''
operation = 'decrypt'
operation_past = 'decrypted'
operation_progressive = 'decrypting'
input_help = 'Name of the file to %(operation)s. Reads from stdin if ' \
'not specified.'
output_help = 'Name of the file to write the %(operation_past)s file ' \
'to. Written to stdout if this option is not present.'
expected_cli_args = 1
has_output = True
key_class = rsa.PublicKey # type: typing.Type[rsa.key.AbstractKey]
def __init__(self) -> None:
self.usage = self.usage % self.__class__.__dict__
self.input_help = self.input_help % self.__class__.__dict__
self.output_help = self.output_help % self.__class__.__dict__
@abc.abstractmethod
def perform_operation(self, indata: bytes, key: rsa.key.AbstractKey,
cli_args: Indexable) -> typing.Any:
"""Performs the program's operation.
Implement in a subclass.
:returns: the data to write to the output.
"""
def __call__(self) -> None:
"""Runs the program."""
(cli, cli_args) = self.parse_cli()
key = self.read_key(cli_args[0], cli.keyform)
indata = self.read_infile(cli.input)
print(self.operation_progressive.title(), file=sys.stderr)
outdata = self.perform_operation(indata, key, cli_args)
if self.has_output:
self.write_outfile(outdata, cli.output)
def parse_cli(self) -> typing.Tuple[optparse.Values, typing.List[str]]:
"""Parse the CLI options
:returns: (cli_opts, cli_args)
"""
parser = optparse.OptionParser(usage=self.usage, description=self.description)
parser.add_option('-i', '--input', type='string', help=self.input_help)
if self.has_output:
parser.add_option('-o', '--output', type='string', help=self.output_help)
parser.add_option('--keyform',
help='Key format of the %s key - default PEM' % self.keyname,
choices=('PEM', 'DER'), default='PEM')
(cli, cli_args) = parser.parse_args(sys.argv[1:])
if len(cli_args) != self.expected_cli_args:
parser.print_help()
raise SystemExit(1)
return cli, cli_args
def read_key(self, filename: str, keyform: str) -> rsa.key.AbstractKey:
"""Reads a public or private key."""
print('Reading %s key from %s' % (self.keyname, filename), file=sys.stderr)
with open(filename, 'rb') as keyfile:
keydata = keyfile.read()
return self.key_class.load_pkcs1(keydata, keyform)
def read_infile(self, inname: str) -> bytes:
"""Read the input file"""
if inname:
print('Reading input from %s' % inname, file=sys.stderr)
with open(inname, 'rb') as infile:
return infile.read()
print('Reading input from stdin', file=sys.stderr)
return sys.stdin.buffer.read()
def write_outfile(self, outdata: bytes, outname: str) -> None:
"""Write the output file"""
if outname:
print('Writing output to %s' % outname, file=sys.stderr)
with open(outname, 'wb') as outfile:
outfile.write(outdata)
else:
print('Writing output to stdout', file=sys.stderr)
sys.stdout.buffer.write(outdata)
class EncryptOperation(CryptoOperation):
"""Encrypts a file."""
keyname = 'public'
description = ('Encrypts a file. The file must be shorter than the key '
'length in order to be encrypted.')
operation = 'encrypt'
operation_past = 'encrypted'
operation_progressive = 'encrypting'
def perform_operation(self, indata: bytes, pub_key: rsa.key.AbstractKey,
cli_args: Indexable = ()) -> bytes:
"""Encrypts files."""
assert isinstance(pub_key, rsa.key.PublicKey)
return rsa.encrypt(indata, pub_key)
class DecryptOperation(CryptoOperation):
"""Decrypts a file."""
keyname = 'private'
description = ('Decrypts a file. The original file must be shorter than '
'the key length in order to have been encrypted.')
operation = 'decrypt'
operation_past = 'decrypted'
operation_progressive = 'decrypting'
key_class = rsa.PrivateKey
def perform_operation(self, indata: bytes, priv_key: rsa.key.AbstractKey,
cli_args: Indexable = ()) -> bytes:
"""Decrypts files."""
assert isinstance(priv_key, rsa.key.PrivateKey)
return rsa.decrypt(indata, priv_key)
class SignOperation(CryptoOperation):
"""Signs a file."""
keyname = 'private'
usage = 'usage: %%prog [options] private_key hash_method'
description = ('Signs a file, outputs the signature. Choose the hash '
'method from %s' % ', '.join(HASH_METHODS))
operation = 'sign'
operation_past = 'signature'
operation_progressive = 'Signing'
key_class = rsa.PrivateKey
expected_cli_args = 2
output_help = ('Name of the file to write the signature to. Written '
'to stdout if this option is not present.')
def perform_operation(self, indata: bytes, priv_key: rsa.key.AbstractKey,
cli_args: Indexable) -> bytes:
"""Signs files."""
assert isinstance(priv_key, rsa.key.PrivateKey)
hash_method = cli_args[1]
if hash_method not in HASH_METHODS:
raise SystemExit('Invalid hash method, choose one of %s' %
', '.join(HASH_METHODS))
return rsa.sign(indata, priv_key, hash_method)
class VerifyOperation(CryptoOperation):
"""Verify a signature."""
keyname = 'public'
usage = 'usage: %%prog [options] public_key signature_file'
description = ('Verifies a signature, exits with status 0 upon success, '
'prints an error message and exits with status 1 upon error.')
operation = 'verify'
operation_past = 'verified'
operation_progressive = 'Verifying'
key_class = rsa.PublicKey
expected_cli_args = 2
has_output = False
def perform_operation(self, indata: bytes, pub_key: rsa.key.AbstractKey,
cli_args: Indexable) -> None:
"""Verifies files."""
assert isinstance(pub_key, rsa.key.PublicKey)
signature_file = cli_args[1]
with open(signature_file, 'rb') as sigfile:
signature = sigfile.read()
try:
rsa.verify(indata, signature, pub_key)
except rsa.VerificationError:
raise SystemExit('Verification failed.')
print('Verification OK', file=sys.stderr)
encrypt = EncryptOperation()
decrypt = DecryptOperation()
sign = SignOperation()
verify = VerifyOperation()

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# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Common functionality shared by several modules."""
import typing
class NotRelativePrimeError(ValueError):
def __init__(self, a: int, b: int, d: int, msg: str = '') -> None:
super().__init__(msg or "%d and %d are not relatively prime, divider=%i" % (a, b, d))
self.a = a
self.b = b
self.d = d
def bit_size(num: int) -> int:
"""
Number of bits needed to represent a integer excluding any prefix
0 bits.
Usage::
>>> bit_size(1023)
10
>>> bit_size(1024)
11
>>> bit_size(1025)
11
:param num:
Integer value. If num is 0, returns 0. Only the absolute value of the
number is considered. Therefore, signed integers will be abs(num)
before the number's bit length is determined.
:returns:
Returns the number of bits in the integer.
"""
try:
return num.bit_length()
except AttributeError:
raise TypeError('bit_size(num) only supports integers, not %r' % type(num))
def byte_size(number: int) -> int:
"""
Returns the number of bytes required to hold a specific long number.
The number of bytes is rounded up.
Usage::
>>> byte_size(1 << 1023)
128
>>> byte_size((1 << 1024) - 1)
128
>>> byte_size(1 << 1024)
129
:param number:
An unsigned integer
:returns:
The number of bytes required to hold a specific long number.
"""
if number == 0:
return 1
return ceil_div(bit_size(number), 8)
def ceil_div(num: int, div: int) -> int:
"""
Returns the ceiling function of a division between `num` and `div`.
Usage::
>>> ceil_div(100, 7)
15
>>> ceil_div(100, 10)
10
>>> ceil_div(1, 4)
1
:param num: Division's numerator, a number
:param div: Division's divisor, a number
:return: Rounded up result of the division between the parameters.
"""
quanta, mod = divmod(num, div)
if mod:
quanta += 1
return quanta
def extended_gcd(a: int, b: int) -> typing.Tuple[int, int, int]:
"""Returns a tuple (r, i, j) such that r = gcd(a, b) = ia + jb
"""
# r = gcd(a,b) i = multiplicitive inverse of a mod b
# or j = multiplicitive inverse of b mod a
# Neg return values for i or j are made positive mod b or a respectively
# Iterateive Version is faster and uses much less stack space
x = 0
y = 1
lx = 1
ly = 0
oa = a # Remember original a/b to remove
ob = b # negative values from return results
while b != 0:
q = a // b
(a, b) = (b, a % b)
(x, lx) = ((lx - (q * x)), x)
(y, ly) = ((ly - (q * y)), y)
if lx < 0:
lx += ob # If neg wrap modulo orignal b
if ly < 0:
ly += oa # If neg wrap modulo orignal a
return a, lx, ly # Return only positive values
def inverse(x: int, n: int) -> int:
"""Returns the inverse of x % n under multiplication, a.k.a x^-1 (mod n)
>>> inverse(7, 4)
3
>>> (inverse(143, 4) * 143) % 4
1
"""
(divider, inv, _) = extended_gcd(x, n)
if divider != 1:
raise NotRelativePrimeError(x, n, divider)
return inv
def crt(a_values: typing.Iterable[int], modulo_values: typing.Iterable[int]) -> int:
"""Chinese Remainder Theorem.
Calculates x such that x = a[i] (mod m[i]) for each i.
:param a_values: the a-values of the above equation
:param modulo_values: the m-values of the above equation
:returns: x such that x = a[i] (mod m[i]) for each i
>>> crt([2, 3], [3, 5])
8
>>> crt([2, 3, 2], [3, 5, 7])
23
>>> crt([2, 3, 0], [7, 11, 15])
135
"""
m = 1
x = 0
for modulo in modulo_values:
m *= modulo
for (m_i, a_i) in zip(modulo_values, a_values):
M_i = m // m_i
inv = inverse(M_i, m_i)
x = (x + a_i * M_i * inv) % m
return x
if __name__ == '__main__':
import doctest
doctest.testmod()

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# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Core mathematical operations.
This is the actual core RSA implementation, which is only defined
mathematically on integers.
"""
def assert_int(var: int, name: str) -> None:
if isinstance(var, int):
return
raise TypeError('%s should be an integer, not %s' % (name, var.__class__))
def encrypt_int(message: int, ekey: int, n: int) -> int:
"""Encrypts a message using encryption key 'ekey', working modulo n"""
assert_int(message, 'message')
assert_int(ekey, 'ekey')
assert_int(n, 'n')
if message < 0:
raise ValueError('Only non-negative numbers are supported')
if message > n:
raise OverflowError("The message %i is too long for n=%i" % (message, n))
return pow(message, ekey, n)
def decrypt_int(cyphertext: int, dkey: int, n: int) -> int:
"""Decrypts a cypher text using the decryption key 'dkey', working modulo n"""
assert_int(cyphertext, 'cyphertext')
assert_int(dkey, 'dkey')
assert_int(n, 'n')
message = pow(cyphertext, dkey, n)
return message

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@ -0,0 +1,803 @@
# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""RSA key generation code.
Create new keys with the newkeys() function. It will give you a PublicKey and a
PrivateKey object.
Loading and saving keys requires the pyasn1 module. This module is imported as
late as possible, such that other functionality will remain working in absence
of pyasn1.
.. note::
Storing public and private keys via the `pickle` module is possible.
However, it is insecure to load a key from an untrusted source.
The pickle module is not secure against erroneous or maliciously
constructed data. Never unpickle data received from an untrusted
or unauthenticated source.
"""
import logging
import typing
import warnings
import rsa.prime
import rsa.pem
import rsa.common
import rsa.randnum
import rsa.core
log = logging.getLogger(__name__)
DEFAULT_EXPONENT = 65537
class AbstractKey:
"""Abstract superclass for private and public keys."""
__slots__ = ('n', 'e')
def __init__(self, n: int, e: int) -> None:
self.n = n
self.e = e
@classmethod
def _load_pkcs1_pem(cls, keyfile: bytes) -> 'AbstractKey':
"""Loads a key in PKCS#1 PEM format, implement in a subclass.
:param keyfile: contents of a PEM-encoded file that contains
the public key.
:type keyfile: bytes
:return: the loaded key
:rtype: AbstractKey
"""
@classmethod
def _load_pkcs1_der(cls, keyfile: bytes) -> 'AbstractKey':
"""Loads a key in PKCS#1 PEM format, implement in a subclass.
:param keyfile: contents of a DER-encoded file that contains
the public key.
:type keyfile: bytes
:return: the loaded key
:rtype: AbstractKey
"""
def _save_pkcs1_pem(self) -> bytes:
"""Saves the key in PKCS#1 PEM format, implement in a subclass.
:returns: the PEM-encoded key.
:rtype: bytes
"""
def _save_pkcs1_der(self) -> bytes:
"""Saves the key in PKCS#1 DER format, implement in a subclass.
:returns: the DER-encoded key.
:rtype: bytes
"""
@classmethod
def load_pkcs1(cls, keyfile: bytes, format: str = 'PEM') -> 'AbstractKey':
"""Loads a key in PKCS#1 DER or PEM format.
:param keyfile: contents of a DER- or PEM-encoded file that contains
the key.
:type keyfile: bytes
:param format: the format of the file to load; 'PEM' or 'DER'
:type format: str
:return: the loaded key
:rtype: AbstractKey
"""
methods = {
'PEM': cls._load_pkcs1_pem,
'DER': cls._load_pkcs1_der,
}
method = cls._assert_format_exists(format, methods)
return method(keyfile)
@staticmethod
def _assert_format_exists(file_format: str, methods: typing.Mapping[str, typing.Callable]) \
-> typing.Callable:
"""Checks whether the given file format exists in 'methods'.
"""
try:
return methods[file_format]
except KeyError:
formats = ', '.join(sorted(methods.keys()))
raise ValueError('Unsupported format: %r, try one of %s' % (file_format,
formats))
def save_pkcs1(self, format: str = 'PEM') -> bytes:
"""Saves the key in PKCS#1 DER or PEM format.
:param format: the format to save; 'PEM' or 'DER'
:type format: str
:returns: the DER- or PEM-encoded key.
:rtype: bytes
"""
methods = {
'PEM': self._save_pkcs1_pem,
'DER': self._save_pkcs1_der,
}
method = self._assert_format_exists(format, methods)
return method()
def blind(self, message: int, r: int) -> int:
"""Performs blinding on the message using random number 'r'.
:param message: the message, as integer, to blind.
:type message: int
:param r: the random number to blind with.
:type r: int
:return: the blinded message.
:rtype: int
The blinding is such that message = unblind(decrypt(blind(encrypt(message))).
See https://en.wikipedia.org/wiki/Blinding_%28cryptography%29
"""
return (message * pow(r, self.e, self.n)) % self.n
def unblind(self, blinded: int, r: int) -> int:
"""Performs blinding on the message using random number 'r'.
:param blinded: the blinded message, as integer, to unblind.
:param r: the random number to unblind with.
:return: the original message.
The blinding is such that message = unblind(decrypt(blind(encrypt(message))).
See https://en.wikipedia.org/wiki/Blinding_%28cryptography%29
"""
return (rsa.common.inverse(r, self.n) * blinded) % self.n
class PublicKey(AbstractKey):
"""Represents a public RSA key.
This key is also known as the 'encryption key'. It contains the 'n' and 'e'
values.
Supports attributes as well as dictionary-like access. Attribute access is
faster, though.
>>> PublicKey(5, 3)
PublicKey(5, 3)
>>> key = PublicKey(5, 3)
>>> key.n
5
>>> key['n']
5
>>> key.e
3
>>> key['e']
3
"""
__slots__ = ('n', 'e')
def __getitem__(self, key: str) -> int:
return getattr(self, key)
def __repr__(self) -> str:
return 'PublicKey(%i, %i)' % (self.n, self.e)
def __getstate__(self) -> typing.Tuple[int, int]:
"""Returns the key as tuple for pickling."""
return self.n, self.e
def __setstate__(self, state: typing.Tuple[int, int]) -> None:
"""Sets the key from tuple."""
self.n, self.e = state
def __eq__(self, other: typing.Any) -> bool:
if other is None:
return False
if not isinstance(other, PublicKey):
return False
return self.n == other.n and self.e == other.e
def __ne__(self, other: typing.Any) -> bool:
return not (self == other)
def __hash__(self) -> int:
return hash((self.n, self.e))
@classmethod
def _load_pkcs1_der(cls, keyfile: bytes) -> 'PublicKey':
"""Loads a key in PKCS#1 DER format.
:param keyfile: contents of a DER-encoded file that contains the public
key.
:return: a PublicKey object
First let's construct a DER encoded key:
>>> import base64
>>> b64der = 'MAwCBQCNGmYtAgMBAAE='
>>> der = base64.standard_b64decode(b64der)
This loads the file:
>>> PublicKey._load_pkcs1_der(der)
PublicKey(2367317549, 65537)
"""
from pyasn1.codec.der import decoder
from rsa.asn1 import AsnPubKey
(priv, _) = decoder.decode(keyfile, asn1Spec=AsnPubKey())
return cls(n=int(priv['modulus']), e=int(priv['publicExponent']))
def _save_pkcs1_der(self) -> bytes:
"""Saves the public key in PKCS#1 DER format.
:returns: the DER-encoded public key.
:rtype: bytes
"""
from pyasn1.codec.der import encoder
from rsa.asn1 import AsnPubKey
# Create the ASN object
asn_key = AsnPubKey()
asn_key.setComponentByName('modulus', self.n)
asn_key.setComponentByName('publicExponent', self.e)
return encoder.encode(asn_key)
@classmethod
def _load_pkcs1_pem(cls, keyfile: bytes) -> 'PublicKey':
"""Loads a PKCS#1 PEM-encoded public key file.
The contents of the file before the "-----BEGIN RSA PUBLIC KEY-----" and
after the "-----END RSA PUBLIC KEY-----" lines is ignored.
:param keyfile: contents of a PEM-encoded file that contains the public
key.
:return: a PublicKey object
"""
der = rsa.pem.load_pem(keyfile, 'RSA PUBLIC KEY')
return cls._load_pkcs1_der(der)
def _save_pkcs1_pem(self) -> bytes:
"""Saves a PKCS#1 PEM-encoded public key file.
:return: contents of a PEM-encoded file that contains the public key.
:rtype: bytes
"""
der = self._save_pkcs1_der()
return rsa.pem.save_pem(der, 'RSA PUBLIC KEY')
@classmethod
def load_pkcs1_openssl_pem(cls, keyfile: bytes) -> 'PublicKey':
"""Loads a PKCS#1.5 PEM-encoded public key file from OpenSSL.
These files can be recognised in that they start with BEGIN PUBLIC KEY
rather than BEGIN RSA PUBLIC KEY.
The contents of the file before the "-----BEGIN PUBLIC KEY-----" and
after the "-----END PUBLIC KEY-----" lines is ignored.
:param keyfile: contents of a PEM-encoded file that contains the public
key, from OpenSSL.
:type keyfile: bytes
:return: a PublicKey object
"""
der = rsa.pem.load_pem(keyfile, 'PUBLIC KEY')
return cls.load_pkcs1_openssl_der(der)
@classmethod
def load_pkcs1_openssl_der(cls, keyfile: bytes) -> 'PublicKey':
"""Loads a PKCS#1 DER-encoded public key file from OpenSSL.
:param keyfile: contents of a DER-encoded file that contains the public
key, from OpenSSL.
:return: a PublicKey object
"""
from rsa.asn1 import OpenSSLPubKey
from pyasn1.codec.der import decoder
from pyasn1.type import univ
(keyinfo, _) = decoder.decode(keyfile, asn1Spec=OpenSSLPubKey())
if keyinfo['header']['oid'] != univ.ObjectIdentifier('1.2.840.113549.1.1.1'):
raise TypeError("This is not a DER-encoded OpenSSL-compatible public key")
return cls._load_pkcs1_der(keyinfo['key'][1:])
class PrivateKey(AbstractKey):
"""Represents a private RSA key.
This key is also known as the 'decryption key'. It contains the 'n', 'e',
'd', 'p', 'q' and other values.
Supports attributes as well as dictionary-like access. Attribute access is
faster, though.
>>> PrivateKey(3247, 65537, 833, 191, 17)
PrivateKey(3247, 65537, 833, 191, 17)
exp1, exp2 and coef will be calculated:
>>> pk = PrivateKey(3727264081, 65537, 3349121513, 65063, 57287)
>>> pk.exp1
55063
>>> pk.exp2
10095
>>> pk.coef
50797
"""
__slots__ = ('n', 'e', 'd', 'p', 'q', 'exp1', 'exp2', 'coef')
def __init__(self, n: int, e: int, d: int, p: int, q: int) -> None:
AbstractKey.__init__(self, n, e)
self.d = d
self.p = p
self.q = q
# Calculate exponents and coefficient.
self.exp1 = int(d % (p - 1))
self.exp2 = int(d % (q - 1))
self.coef = rsa.common.inverse(q, p)
def __getitem__(self, key: str) -> int:
return getattr(self, key)
def __repr__(self) -> str:
return 'PrivateKey(%i, %i, %i, %i, %i)' % (self.n, self.e, self.d, self.p, self.q)
def __getstate__(self) -> typing.Tuple[int, int, int, int, int, int, int, int]:
"""Returns the key as tuple for pickling."""
return self.n, self.e, self.d, self.p, self.q, self.exp1, self.exp2, self.coef
def __setstate__(self, state: typing.Tuple[int, int, int, int, int, int, int, int]) -> None:
"""Sets the key from tuple."""
self.n, self.e, self.d, self.p, self.q, self.exp1, self.exp2, self.coef = state
def __eq__(self, other: typing.Any) -> bool:
if other is None:
return False
if not isinstance(other, PrivateKey):
return False
return (self.n == other.n and
self.e == other.e and
self.d == other.d and
self.p == other.p and
self.q == other.q and
self.exp1 == other.exp1 and
self.exp2 == other.exp2 and
self.coef == other.coef)
def __ne__(self, other: typing.Any) -> bool:
return not (self == other)
def __hash__(self) -> int:
return hash((self.n, self.e, self.d, self.p, self.q, self.exp1, self.exp2, self.coef))
def _get_blinding_factor(self) -> int:
for _ in range(1000):
blind_r = rsa.randnum.randint(self.n - 1)
if rsa.prime.are_relatively_prime(self.n, blind_r):
return blind_r
raise RuntimeError('unable to find blinding factor')
def blinded_decrypt(self, encrypted: int) -> int:
"""Decrypts the message using blinding to prevent side-channel attacks.
:param encrypted: the encrypted message
:type encrypted: int
:returns: the decrypted message
:rtype: int
"""
blind_r = self._get_blinding_factor()
blinded = self.blind(encrypted, blind_r) # blind before decrypting
decrypted = rsa.core.decrypt_int(blinded, self.d, self.n)
return self.unblind(decrypted, blind_r)
def blinded_encrypt(self, message: int) -> int:
"""Encrypts the message using blinding to prevent side-channel attacks.
:param message: the message to encrypt
:type message: int
:returns: the encrypted message
:rtype: int
"""
blind_r = self._get_blinding_factor()
blinded = self.blind(message, blind_r) # blind before encrypting
encrypted = rsa.core.encrypt_int(blinded, self.d, self.n)
return self.unblind(encrypted, blind_r)
@classmethod
def _load_pkcs1_der(cls, keyfile: bytes) -> 'PrivateKey':
"""Loads a key in PKCS#1 DER format.
:param keyfile: contents of a DER-encoded file that contains the private
key.
:type keyfile: bytes
:return: a PrivateKey object
First let's construct a DER encoded key:
>>> import base64
>>> b64der = 'MC4CAQACBQDeKYlRAgMBAAECBQDHn4npAgMA/icCAwDfxwIDANcXAgInbwIDAMZt'
>>> der = base64.standard_b64decode(b64der)
This loads the file:
>>> PrivateKey._load_pkcs1_der(der)
PrivateKey(3727264081, 65537, 3349121513, 65063, 57287)
"""
from pyasn1.codec.der import decoder
(priv, _) = decoder.decode(keyfile)
# ASN.1 contents of DER encoded private key:
#
# RSAPrivateKey ::= SEQUENCE {
# version Version,
# modulus INTEGER, -- n
# publicExponent INTEGER, -- e
# privateExponent INTEGER, -- d
# prime1 INTEGER, -- p
# prime2 INTEGER, -- q
# exponent1 INTEGER, -- d mod (p-1)
# exponent2 INTEGER, -- d mod (q-1)
# coefficient INTEGER, -- (inverse of q) mod p
# otherPrimeInfos OtherPrimeInfos OPTIONAL
# }
if priv[0] != 0:
raise ValueError('Unable to read this file, version %s != 0' % priv[0])
as_ints = map(int, priv[1:6])
key = cls(*as_ints)
exp1, exp2, coef = map(int, priv[6:9])
if (key.exp1, key.exp2, key.coef) != (exp1, exp2, coef):
warnings.warn(
'You have provided a malformed keyfile. Either the exponents '
'or the coefficient are incorrect. Using the correct values '
'instead.',
UserWarning,
)
return key
def _save_pkcs1_der(self) -> bytes:
"""Saves the private key in PKCS#1 DER format.
:returns: the DER-encoded private key.
:rtype: bytes
"""
from pyasn1.type import univ, namedtype
from pyasn1.codec.der import encoder
class AsnPrivKey(univ.Sequence):
componentType = namedtype.NamedTypes(
namedtype.NamedType('version', univ.Integer()),
namedtype.NamedType('modulus', univ.Integer()),
namedtype.NamedType('publicExponent', univ.Integer()),
namedtype.NamedType('privateExponent', univ.Integer()),
namedtype.NamedType('prime1', univ.Integer()),
namedtype.NamedType('prime2', univ.Integer()),
namedtype.NamedType('exponent1', univ.Integer()),
namedtype.NamedType('exponent2', univ.Integer()),
namedtype.NamedType('coefficient', univ.Integer()),
)
# Create the ASN object
asn_key = AsnPrivKey()
asn_key.setComponentByName('version', 0)
asn_key.setComponentByName('modulus', self.n)
asn_key.setComponentByName('publicExponent', self.e)
asn_key.setComponentByName('privateExponent', self.d)
asn_key.setComponentByName('prime1', self.p)
asn_key.setComponentByName('prime2', self.q)
asn_key.setComponentByName('exponent1', self.exp1)
asn_key.setComponentByName('exponent2', self.exp2)
asn_key.setComponentByName('coefficient', self.coef)
return encoder.encode(asn_key)
@classmethod
def _load_pkcs1_pem(cls, keyfile: bytes) -> 'PrivateKey':
"""Loads a PKCS#1 PEM-encoded private key file.
The contents of the file before the "-----BEGIN RSA PRIVATE KEY-----" and
after the "-----END RSA PRIVATE KEY-----" lines is ignored.
:param keyfile: contents of a PEM-encoded file that contains the private
key.
:type keyfile: bytes
:return: a PrivateKey object
"""
der = rsa.pem.load_pem(keyfile, b'RSA PRIVATE KEY')
return cls._load_pkcs1_der(der)
def _save_pkcs1_pem(self) -> bytes:
"""Saves a PKCS#1 PEM-encoded private key file.
:return: contents of a PEM-encoded file that contains the private key.
:rtype: bytes
"""
der = self._save_pkcs1_der()
return rsa.pem.save_pem(der, b'RSA PRIVATE KEY')
def find_p_q(nbits: int,
getprime_func: typing.Callable[[int], int] = rsa.prime.getprime,
accurate: bool = True) -> typing.Tuple[int, int]:
"""Returns a tuple of two different primes of nbits bits each.
The resulting p * q has exacty 2 * nbits bits, and the returned p and q
will not be equal.
:param nbits: the number of bits in each of p and q.
:param getprime_func: the getprime function, defaults to
:py:func:`rsa.prime.getprime`.
*Introduced in Python-RSA 3.1*
:param accurate: whether to enable accurate mode or not.
:returns: (p, q), where p > q
>>> (p, q) = find_p_q(128)
>>> from rsa import common
>>> common.bit_size(p * q)
256
When not in accurate mode, the number of bits can be slightly less
>>> (p, q) = find_p_q(128, accurate=False)
>>> from rsa import common
>>> common.bit_size(p * q) <= 256
True
>>> common.bit_size(p * q) > 240
True
"""
total_bits = nbits * 2
# Make sure that p and q aren't too close or the factoring programs can
# factor n.
shift = nbits // 16
pbits = nbits + shift
qbits = nbits - shift
# Choose the two initial primes
log.debug('find_p_q(%i): Finding p', nbits)
p = getprime_func(pbits)
log.debug('find_p_q(%i): Finding q', nbits)
q = getprime_func(qbits)
def is_acceptable(p: int, q: int) -> bool:
"""Returns True iff p and q are acceptable:
- p and q differ
- (p * q) has the right nr of bits (when accurate=True)
"""
if p == q:
return False
if not accurate:
return True
# Make sure we have just the right amount of bits
found_size = rsa.common.bit_size(p * q)
return total_bits == found_size
# Keep choosing other primes until they match our requirements.
change_p = False
while not is_acceptable(p, q):
# Change p on one iteration and q on the other
if change_p:
p = getprime_func(pbits)
else:
q = getprime_func(qbits)
change_p = not change_p
# We want p > q as described on
# http://www.di-mgt.com.au/rsa_alg.html#crt
return max(p, q), min(p, q)
def calculate_keys_custom_exponent(p: int, q: int, exponent: int) -> typing.Tuple[int, int]:
"""Calculates an encryption and a decryption key given p, q and an exponent,
and returns them as a tuple (e, d)
:param p: the first large prime
:param q: the second large prime
:param exponent: the exponent for the key; only change this if you know
what you're doing, as the exponent influences how difficult your
private key can be cracked. A very common choice for e is 65537.
:type exponent: int
"""
phi_n = (p - 1) * (q - 1)
try:
d = rsa.common.inverse(exponent, phi_n)
except rsa.common.NotRelativePrimeError as ex:
raise rsa.common.NotRelativePrimeError(
exponent, phi_n, ex.d,
msg="e (%d) and phi_n (%d) are not relatively prime (divider=%i)" %
(exponent, phi_n, ex.d))
if (exponent * d) % phi_n != 1:
raise ValueError("e (%d) and d (%d) are not mult. inv. modulo "
"phi_n (%d)" % (exponent, d, phi_n))
return exponent, d
def calculate_keys(p: int, q: int) -> typing.Tuple[int, int]:
"""Calculates an encryption and a decryption key given p and q, and
returns them as a tuple (e, d)
:param p: the first large prime
:param q: the second large prime
:return: tuple (e, d) with the encryption and decryption exponents.
"""
return calculate_keys_custom_exponent(p, q, DEFAULT_EXPONENT)
def gen_keys(nbits: int,
getprime_func: typing.Callable[[int], int],
accurate: bool = True,
exponent: int = DEFAULT_EXPONENT) -> typing.Tuple[int, int, int, int]:
"""Generate RSA keys of nbits bits. Returns (p, q, e, d).
Note: this can take a long time, depending on the key size.
:param nbits: the total number of bits in ``p`` and ``q``. Both ``p`` and
``q`` will use ``nbits/2`` bits.
:param getprime_func: either :py:func:`rsa.prime.getprime` or a function
with similar signature.
:param exponent: the exponent for the key; only change this if you know
what you're doing, as the exponent influences how difficult your
private key can be cracked. A very common choice for e is 65537.
:type exponent: int
"""
# Regenerate p and q values, until calculate_keys doesn't raise a
# ValueError.
while True:
(p, q) = find_p_q(nbits // 2, getprime_func, accurate)
try:
(e, d) = calculate_keys_custom_exponent(p, q, exponent=exponent)
break
except ValueError:
pass
return p, q, e, d
def newkeys(nbits: int,
accurate: bool = True,
poolsize: int = 1,
exponent: int = DEFAULT_EXPONENT) -> typing.Tuple[PublicKey, PrivateKey]:
"""Generates public and private keys, and returns them as (pub, priv).
The public key is also known as the 'encryption key', and is a
:py:class:`rsa.PublicKey` object. The private key is also known as the
'decryption key' and is a :py:class:`rsa.PrivateKey` object.
:param nbits: the number of bits required to store ``n = p*q``.
:param accurate: when True, ``n`` will have exactly the number of bits you
asked for. However, this makes key generation much slower. When False,
`n`` may have slightly less bits.
:param poolsize: the number of processes to use to generate the prime
numbers. If set to a number > 1, a parallel algorithm will be used.
This requires Python 2.6 or newer.
:param exponent: the exponent for the key; only change this if you know
what you're doing, as the exponent influences how difficult your
private key can be cracked. A very common choice for e is 65537.
:type exponent: int
:returns: a tuple (:py:class:`rsa.PublicKey`, :py:class:`rsa.PrivateKey`)
The ``poolsize`` parameter was added in *Python-RSA 3.1* and requires
Python 2.6 or newer.
"""
if nbits < 16:
raise ValueError('Key too small')
if poolsize < 1:
raise ValueError('Pool size (%i) should be >= 1' % poolsize)
# Determine which getprime function to use
if poolsize > 1:
from rsa import parallel
def getprime_func(nbits: int) -> int:
return parallel.getprime(nbits, poolsize=poolsize)
else:
getprime_func = rsa.prime.getprime
# Generate the key components
(p, q, e, d) = gen_keys(nbits, getprime_func, accurate=accurate, exponent=exponent)
# Create the key objects
n = p * q
return (
PublicKey(n, e),
PrivateKey(n, e, d, p, q)
)
__all__ = ['PublicKey', 'PrivateKey', 'newkeys']
if __name__ == '__main__':
import doctest
try:
for count in range(100):
(failures, tests) = doctest.testmod()
if failures:
break
if (count % 10 == 0 and count) or count == 1:
print('%i times' % count)
except KeyboardInterrupt:
print('Aborted')
else:
print('Doctests done')

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@ -0,0 +1,97 @@
# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Functions for parallel computation on multiple cores.
Introduced in Python-RSA 3.1.
.. note::
Requires Python 2.6 or newer.
"""
import multiprocessing as mp
from multiprocessing.connection import Connection
import rsa.prime
import rsa.randnum
def _find_prime(nbits: int, pipe: Connection) -> None:
while True:
integer = rsa.randnum.read_random_odd_int(nbits)
# Test for primeness
if rsa.prime.is_prime(integer):
pipe.send(integer)
return
def getprime(nbits: int, poolsize: int) -> int:
"""Returns a prime number that can be stored in 'nbits' bits.
Works in multiple threads at the same time.
>>> p = getprime(128, 3)
>>> rsa.prime.is_prime(p-1)
False
>>> rsa.prime.is_prime(p)
True
>>> rsa.prime.is_prime(p+1)
False
>>> from rsa import common
>>> common.bit_size(p) == 128
True
"""
(pipe_recv, pipe_send) = mp.Pipe(duplex=False)
# Create processes
try:
procs = [mp.Process(target=_find_prime, args=(nbits, pipe_send))
for _ in range(poolsize)]
# Start processes
for p in procs:
p.start()
result = pipe_recv.recv()
finally:
pipe_recv.close()
pipe_send.close()
# Terminate processes
for p in procs:
p.terminate()
return result
__all__ = ['getprime']
if __name__ == '__main__':
print('Running doctests 1000x or until failure')
import doctest
for count in range(100):
(failures, tests) = doctest.testmod()
if failures:
break
if count % 10 == 0 and count:
print('%i times' % count)
print('Doctests done')

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# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Functions that load and write PEM-encoded files."""
import base64
import typing
# Should either be ASCII strings or bytes.
FlexiText = typing.Union[str, bytes]
def _markers(pem_marker: FlexiText) -> typing.Tuple[bytes, bytes]:
"""
Returns the start and end PEM markers, as bytes.
"""
if not isinstance(pem_marker, bytes):
pem_marker = pem_marker.encode('ascii')
return (b'-----BEGIN ' + pem_marker + b'-----',
b'-----END ' + pem_marker + b'-----')
def _pem_lines(contents: bytes, pem_start: bytes, pem_end: bytes) -> typing.Iterator[bytes]:
"""Generator over PEM lines between pem_start and pem_end."""
in_pem_part = False
seen_pem_start = False
for line in contents.splitlines():
line = line.strip()
# Skip empty lines
if not line:
continue
# Handle start marker
if line == pem_start:
if in_pem_part:
raise ValueError('Seen start marker "%r" twice' % pem_start)
in_pem_part = True
seen_pem_start = True
continue
# Skip stuff before first marker
if not in_pem_part:
continue
# Handle end marker
if in_pem_part and line == pem_end:
in_pem_part = False
break
# Load fields
if b':' in line:
continue
yield line
# Do some sanity checks
if not seen_pem_start:
raise ValueError('No PEM start marker "%r" found' % pem_start)
if in_pem_part:
raise ValueError('No PEM end marker "%r" found' % pem_end)
def load_pem(contents: FlexiText, pem_marker: FlexiText) -> bytes:
"""Loads a PEM file.
:param contents: the contents of the file to interpret
:param pem_marker: the marker of the PEM content, such as 'RSA PRIVATE KEY'
when your file has '-----BEGIN RSA PRIVATE KEY-----' and
'-----END RSA PRIVATE KEY-----' markers.
:return: the base64-decoded content between the start and end markers.
@raise ValueError: when the content is invalid, for example when the start
marker cannot be found.
"""
# We want bytes, not text. If it's text, it can be converted to ASCII bytes.
if not isinstance(contents, bytes):
contents = contents.encode('ascii')
(pem_start, pem_end) = _markers(pem_marker)
pem_lines = [line for line in _pem_lines(contents, pem_start, pem_end)]
# Base64-decode the contents
pem = b''.join(pem_lines)
return base64.standard_b64decode(pem)
def save_pem(contents: bytes, pem_marker: FlexiText) -> bytes:
"""Saves a PEM file.
:param contents: the contents to encode in PEM format
:param pem_marker: the marker of the PEM content, such as 'RSA PRIVATE KEY'
when your file has '-----BEGIN RSA PRIVATE KEY-----' and
'-----END RSA PRIVATE KEY-----' markers.
:return: the base64-encoded content between the start and end markers, as bytes.
"""
(pem_start, pem_end) = _markers(pem_marker)
b64 = base64.standard_b64encode(contents).replace(b'\n', b'')
pem_lines = [pem_start]
for block_start in range(0, len(b64), 64):
block = b64[block_start:block_start + 64]
pem_lines.append(block)
pem_lines.append(pem_end)
pem_lines.append(b'')
return b'\n'.join(pem_lines)

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# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Functions for PKCS#1 version 1.5 encryption and signing
This module implements certain functionality from PKCS#1 version 1.5. For a
very clear example, read http://www.di-mgt.com.au/rsa_alg.html#pkcs1schemes
At least 8 bytes of random padding is used when encrypting a message. This makes
these methods much more secure than the ones in the ``rsa`` module.
WARNING: this module leaks information when decryption fails. The exceptions
that are raised contain the Python traceback information, which can be used to
deduce where in the process the failure occurred. DO NOT PASS SUCH INFORMATION
to your users.
"""
import hashlib
import os
import sys
import typing
from . import common, transform, core, key
# ASN.1 codes that describe the hash algorithm used.
HASH_ASN1 = {
'MD5': b'\x30\x20\x30\x0c\x06\x08\x2a\x86\x48\x86\xf7\x0d\x02\x05\x05\x00\x04\x10',
'SHA-1': b'\x30\x21\x30\x09\x06\x05\x2b\x0e\x03\x02\x1a\x05\x00\x04\x14',
'SHA-224': b'\x30\x2d\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x04\x05\x00\x04\x1c',
'SHA-256': b'\x30\x31\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x01\x05\x00\x04\x20',
'SHA-384': b'\x30\x41\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x02\x05\x00\x04\x30',
'SHA-512': b'\x30\x51\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x03\x05\x00\x04\x40',
}
HASH_METHODS = {
'MD5': hashlib.md5,
'SHA-1': hashlib.sha1,
'SHA-224': hashlib.sha224,
'SHA-256': hashlib.sha256,
'SHA-384': hashlib.sha384,
'SHA-512': hashlib.sha512,
}
if sys.version_info >= (3, 6):
# Python 3.6 introduced SHA3 support.
HASH_ASN1.update({
'SHA3-256': b'\x30\x31\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x08\x05\x00\x04\x20',
'SHA3-384': b'\x30\x41\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x09\x05\x00\x04\x30',
'SHA3-512': b'\x30\x51\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x0a\x05\x00\x04\x40',
})
HASH_METHODS.update({
'SHA3-256': hashlib.sha3_256,
'SHA3-384': hashlib.sha3_384,
'SHA3-512': hashlib.sha3_512,
})
class CryptoError(Exception):
"""Base class for all exceptions in this module."""
class DecryptionError(CryptoError):
"""Raised when decryption fails."""
class VerificationError(CryptoError):
"""Raised when verification fails."""
def _pad_for_encryption(message: bytes, target_length: int) -> bytes:
r"""Pads the message for encryption, returning the padded message.
:return: 00 02 RANDOM_DATA 00 MESSAGE
>>> block = _pad_for_encryption(b'hello', 16)
>>> len(block)
16
>>> block[0:2]
b'\x00\x02'
>>> block[-6:]
b'\x00hello'
"""
max_msglength = target_length - 11
msglength = len(message)
if msglength > max_msglength:
raise OverflowError('%i bytes needed for message, but there is only'
' space for %i' % (msglength, max_msglength))
# Get random padding
padding = b''
padding_length = target_length - msglength - 3
# We remove 0-bytes, so we'll end up with less padding than we've asked for,
# so keep adding data until we're at the correct length.
while len(padding) < padding_length:
needed_bytes = padding_length - len(padding)
# Always read at least 8 bytes more than we need, and trim off the rest
# after removing the 0-bytes. This increases the chance of getting
# enough bytes, especially when needed_bytes is small
new_padding = os.urandom(needed_bytes + 5)
new_padding = new_padding.replace(b'\x00', b'')
padding = padding + new_padding[:needed_bytes]
assert len(padding) == padding_length
return b''.join([b'\x00\x02',
padding,
b'\x00',
message])
def _pad_for_signing(message: bytes, target_length: int) -> bytes:
r"""Pads the message for signing, returning the padded message.
The padding is always a repetition of FF bytes.
:return: 00 01 PADDING 00 MESSAGE
>>> block = _pad_for_signing(b'hello', 16)
>>> len(block)
16
>>> block[0:2]
b'\x00\x01'
>>> block[-6:]
b'\x00hello'
>>> block[2:-6]
b'\xff\xff\xff\xff\xff\xff\xff\xff'
"""
max_msglength = target_length - 11
msglength = len(message)
if msglength > max_msglength:
raise OverflowError('%i bytes needed for message, but there is only'
' space for %i' % (msglength, max_msglength))
padding_length = target_length - msglength - 3
return b''.join([b'\x00\x01',
padding_length * b'\xff',
b'\x00',
message])
def encrypt(message: bytes, pub_key: key.PublicKey) -> bytes:
"""Encrypts the given message using PKCS#1 v1.5
:param message: the message to encrypt. Must be a byte string no longer than
``k-11`` bytes, where ``k`` is the number of bytes needed to encode
the ``n`` component of the public key.
:param pub_key: the :py:class:`rsa.PublicKey` to encrypt with.
:raise OverflowError: when the message is too large to fit in the padded
block.
>>> from rsa import key, common
>>> (pub_key, priv_key) = key.newkeys(256)
>>> message = b'hello'
>>> crypto = encrypt(message, pub_key)
The crypto text should be just as long as the public key 'n' component:
>>> len(crypto) == common.byte_size(pub_key.n)
True
"""
keylength = common.byte_size(pub_key.n)
padded = _pad_for_encryption(message, keylength)
payload = transform.bytes2int(padded)
encrypted = core.encrypt_int(payload, pub_key.e, pub_key.n)
block = transform.int2bytes(encrypted, keylength)
return block
def decrypt(crypto: bytes, priv_key: key.PrivateKey) -> bytes:
r"""Decrypts the given message using PKCS#1 v1.5
The decryption is considered 'failed' when the resulting cleartext doesn't
start with the bytes 00 02, or when the 00 byte between the padding and
the message cannot be found.
:param crypto: the crypto text as returned by :py:func:`rsa.encrypt`
:param priv_key: the :py:class:`rsa.PrivateKey` to decrypt with.
:raise DecryptionError: when the decryption fails. No details are given as
to why the code thinks the decryption fails, as this would leak
information about the private key.
>>> import rsa
>>> (pub_key, priv_key) = rsa.newkeys(256)
It works with strings:
>>> crypto = encrypt(b'hello', pub_key)
>>> decrypt(crypto, priv_key)
b'hello'
And with binary data:
>>> crypto = encrypt(b'\x00\x00\x00\x00\x01', pub_key)
>>> decrypt(crypto, priv_key)
b'\x00\x00\x00\x00\x01'
Altering the encrypted information will *likely* cause a
:py:class:`rsa.pkcs1.DecryptionError`. If you want to be *sure*, use
:py:func:`rsa.sign`.
.. warning::
Never display the stack trace of a
:py:class:`rsa.pkcs1.DecryptionError` exception. It shows where in the
code the exception occurred, and thus leaks information about the key.
It's only a tiny bit of information, but every bit makes cracking the
keys easier.
>>> crypto = encrypt(b'hello', pub_key)
>>> crypto = crypto[0:5] + b'X' + crypto[6:] # change a byte
>>> decrypt(crypto, priv_key)
Traceback (most recent call last):
...
rsa.pkcs1.DecryptionError: Decryption failed
"""
blocksize = common.byte_size(priv_key.n)
encrypted = transform.bytes2int(crypto)
decrypted = priv_key.blinded_decrypt(encrypted)
cleartext = transform.int2bytes(decrypted, blocksize)
# Detect leading zeroes in the crypto. These are not reflected in the
# encrypted value (as leading zeroes do not influence the value of an
# integer). This fixes CVE-2020-13757.
if len(crypto) > blocksize:
raise DecryptionError('Decryption failed')
# If we can't find the cleartext marker, decryption failed.
if cleartext[0:2] != b'\x00\x02':
raise DecryptionError('Decryption failed')
# Find the 00 separator between the padding and the message
try:
sep_idx = cleartext.index(b'\x00', 2)
except ValueError:
raise DecryptionError('Decryption failed')
return cleartext[sep_idx + 1:]
def sign_hash(hash_value: bytes, priv_key: key.PrivateKey, hash_method: str) -> bytes:
"""Signs a precomputed hash with the private key.
Hashes the message, then signs the hash with the given key. This is known
as a "detached signature", because the message itself isn't altered.
:param hash_value: A precomputed hash to sign (ignores message).
:param priv_key: the :py:class:`rsa.PrivateKey` to sign with
:param hash_method: the hash method used on the message. Use 'MD5', 'SHA-1',
'SHA-224', SHA-256', 'SHA-384' or 'SHA-512'.
:return: a message signature block.
:raise OverflowError: if the private key is too small to contain the
requested hash.
"""
# Get the ASN1 code for this hash method
if hash_method not in HASH_ASN1:
raise ValueError('Invalid hash method: %s' % hash_method)
asn1code = HASH_ASN1[hash_method]
# Encrypt the hash with the private key
cleartext = asn1code + hash_value
keylength = common.byte_size(priv_key.n)
padded = _pad_for_signing(cleartext, keylength)
payload = transform.bytes2int(padded)
encrypted = priv_key.blinded_encrypt(payload)
block = transform.int2bytes(encrypted, keylength)
return block
def sign(message: bytes, priv_key: key.PrivateKey, hash_method: str) -> bytes:
"""Signs the message with the private key.
Hashes the message, then signs the hash with the given key. This is known
as a "detached signature", because the message itself isn't altered.
:param message: the message to sign. Can be an 8-bit string or a file-like
object. If ``message`` has a ``read()`` method, it is assumed to be a
file-like object.
:param priv_key: the :py:class:`rsa.PrivateKey` to sign with
:param hash_method: the hash method used on the message. Use 'MD5', 'SHA-1',
'SHA-224', SHA-256', 'SHA-384' or 'SHA-512'.
:return: a message signature block.
:raise OverflowError: if the private key is too small to contain the
requested hash.
"""
msg_hash = compute_hash(message, hash_method)
return sign_hash(msg_hash, priv_key, hash_method)
def verify(message: bytes, signature: bytes, pub_key: key.PublicKey) -> str:
"""Verifies that the signature matches the message.
The hash method is detected automatically from the signature.
:param message: the signed message. Can be an 8-bit string or a file-like
object. If ``message`` has a ``read()`` method, it is assumed to be a
file-like object.
:param signature: the signature block, as created with :py:func:`rsa.sign`.
:param pub_key: the :py:class:`rsa.PublicKey` of the person signing the message.
:raise VerificationError: when the signature doesn't match the message.
:returns: the name of the used hash.
"""
keylength = common.byte_size(pub_key.n)
encrypted = transform.bytes2int(signature)
decrypted = core.decrypt_int(encrypted, pub_key.e, pub_key.n)
clearsig = transform.int2bytes(decrypted, keylength)
# Get the hash method
method_name = _find_method_hash(clearsig)
message_hash = compute_hash(message, method_name)
# Reconstruct the expected padded hash
cleartext = HASH_ASN1[method_name] + message_hash
expected = _pad_for_signing(cleartext, keylength)
if len(signature) != keylength:
raise VerificationError('Verification failed')
# Compare with the signed one
if expected != clearsig:
raise VerificationError('Verification failed')
return method_name
def find_signature_hash(signature: bytes, pub_key: key.PublicKey) -> str:
"""Returns the hash name detected from the signature.
If you also want to verify the message, use :py:func:`rsa.verify()` instead.
It also returns the name of the used hash.
:param signature: the signature block, as created with :py:func:`rsa.sign`.
:param pub_key: the :py:class:`rsa.PublicKey` of the person signing the message.
:returns: the name of the used hash.
"""
keylength = common.byte_size(pub_key.n)
encrypted = transform.bytes2int(signature)
decrypted = core.decrypt_int(encrypted, pub_key.e, pub_key.n)
clearsig = transform.int2bytes(decrypted, keylength)
return _find_method_hash(clearsig)
def yield_fixedblocks(infile: typing.BinaryIO, blocksize: int) -> typing.Iterator[bytes]:
"""Generator, yields each block of ``blocksize`` bytes in the input file.
:param infile: file to read and separate in blocks.
:param blocksize: block size in bytes.
:returns: a generator that yields the contents of each block
"""
while True:
block = infile.read(blocksize)
read_bytes = len(block)
if read_bytes == 0:
break
yield block
if read_bytes < blocksize:
break
def compute_hash(message: typing.Union[bytes, typing.BinaryIO], method_name: str) -> bytes:
"""Returns the message digest.
:param message: the signed message. Can be an 8-bit string or a file-like
object. If ``message`` has a ``read()`` method, it is assumed to be a
file-like object.
:param method_name: the hash method, must be a key of
:py:const:`HASH_METHODS`.
"""
if method_name not in HASH_METHODS:
raise ValueError('Invalid hash method: %s' % method_name)
method = HASH_METHODS[method_name]
hasher = method()
if isinstance(message, bytes):
hasher.update(message)
else:
assert hasattr(message, 'read') and hasattr(message.read, '__call__')
# read as 1K blocks
for block in yield_fixedblocks(message, 1024):
hasher.update(block)
return hasher.digest()
def _find_method_hash(clearsig: bytes) -> str:
"""Finds the hash method.
:param clearsig: full padded ASN1 and hash.
:return: the used hash method.
:raise VerificationFailed: when the hash method cannot be found
"""
for (hashname, asn1code) in HASH_ASN1.items():
if asn1code in clearsig:
return hashname
raise VerificationError('Verification failed')
__all__ = ['encrypt', 'decrypt', 'sign', 'verify',
'DecryptionError', 'VerificationError', 'CryptoError']
if __name__ == '__main__':
print('Running doctests 1000x or until failure')
import doctest
for count in range(1000):
(failures, tests) = doctest.testmod()
if failures:
break
if count % 100 == 0 and count:
print('%i times' % count)
print('Doctests done')

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# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Functions for PKCS#1 version 2 encryption and signing
This module implements certain functionality from PKCS#1 version 2. Main
documentation is RFC 2437: https://tools.ietf.org/html/rfc2437
"""
from rsa import (
common,
pkcs1,
transform,
)
def mgf1(seed: bytes, length: int, hasher: str = 'SHA-1') -> bytes:
"""
MGF1 is a Mask Generation Function based on a hash function.
A mask generation function takes an octet string of variable length and a
desired output length as input, and outputs an octet string of the desired
length. The plaintext-awareness of RSAES-OAEP relies on the random nature of
the output of the mask generation function, which in turn relies on the
random nature of the underlying hash.
:param bytes seed: seed from which mask is generated, an octet string
:param int length: intended length in octets of the mask, at most 2^32(hLen)
:param str hasher: hash function (hLen denotes the length in octets of the hash
function output)
:return: mask, an octet string of length `length`
:rtype: bytes
:raise OverflowError: when `length` is too large for the specified `hasher`
:raise ValueError: when specified `hasher` is invalid
"""
try:
hash_length = pkcs1.HASH_METHODS[hasher]().digest_size
except KeyError:
raise ValueError(
'Invalid `hasher` specified. Please select one of: {hash_list}'.format(
hash_list=', '.join(sorted(pkcs1.HASH_METHODS.keys()))
)
)
# If l > 2^32(hLen), output "mask too long" and stop.
if length > (2**32 * hash_length):
raise OverflowError(
"Desired length should be at most 2**32 times the hasher's output "
"length ({hash_length} for {hasher} function)".format(
hash_length=hash_length,
hasher=hasher,
)
)
# Looping `counter` from 0 to ceil(l / hLen)-1, build `output` based on the
# hashes formed by (`seed` + C), being `C` an octet string of length 4
# generated by converting `counter` with the primitive I2OSP
output = b''.join(
pkcs1.compute_hash(
seed + transform.int2bytes(counter, fill_size=4),
method_name=hasher,
)
for counter in range(common.ceil_div(length, hash_length) + 1)
)
# Output the leading `length` octets of `output` as the octet string mask.
return output[:length]
__all__ = [
'mgf1',
]
if __name__ == '__main__':
print('Running doctests 1000x or until failure')
import doctest
for count in range(1000):
(failures, tests) = doctest.testmod()
if failures:
break
if count % 100 == 0 and count:
print('%i times' % count)
print('Doctests done')

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# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Numerical functions related to primes.
Implementation based on the book Algorithm Design by Michael T. Goodrich and
Roberto Tamassia, 2002.
"""
import rsa.common
import rsa.randnum
__all__ = ['getprime', 'are_relatively_prime']
def gcd(p: int, q: int) -> int:
"""Returns the greatest common divisor of p and q
>>> gcd(48, 180)
12
"""
while q != 0:
(p, q) = (q, p % q)
return p
def get_primality_testing_rounds(number: int) -> int:
"""Returns minimum number of rounds for Miller-Rabing primality testing,
based on number bitsize.
According to NIST FIPS 186-4, Appendix C, Table C.3, minimum number of
rounds of M-R testing, using an error probability of 2 ** (-100), for
different p, q bitsizes are:
* p, q bitsize: 512; rounds: 7
* p, q bitsize: 1024; rounds: 4
* p, q bitsize: 1536; rounds: 3
See: http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-4.pdf
"""
# Calculate number bitsize.
bitsize = rsa.common.bit_size(number)
# Set number of rounds.
if bitsize >= 1536:
return 3
if bitsize >= 1024:
return 4
if bitsize >= 512:
return 7
# For smaller bitsizes, set arbitrary number of rounds.
return 10
def miller_rabin_primality_testing(n: int, k: int) -> bool:
"""Calculates whether n is composite (which is always correct) or prime
(which theoretically is incorrect with error probability 4**-k), by
applying Miller-Rabin primality testing.
For reference and implementation example, see:
https://en.wikipedia.org/wiki/Miller%E2%80%93Rabin_primality_test
:param n: Integer to be tested for primality.
:type n: int
:param k: Number of rounds (witnesses) of Miller-Rabin testing.
:type k: int
:return: False if the number is composite, True if it's probably prime.
:rtype: bool
"""
# prevent potential infinite loop when d = 0
if n < 2:
return False
# Decompose (n - 1) to write it as (2 ** r) * d
# While d is even, divide it by 2 and increase the exponent.
d = n - 1
r = 0
while not (d & 1):
r += 1
d >>= 1
# Test k witnesses.
for _ in range(k):
# Generate random integer a, where 2 <= a <= (n - 2)
a = rsa.randnum.randint(n - 3) + 1
x = pow(a, d, n)
if x == 1 or x == n - 1:
continue
for _ in range(r - 1):
x = pow(x, 2, n)
if x == 1:
# n is composite.
return False
if x == n - 1:
# Exit inner loop and continue with next witness.
break
else:
# If loop doesn't break, n is composite.
return False
return True
def is_prime(number: int) -> bool:
"""Returns True if the number is prime, and False otherwise.
>>> is_prime(2)
True
>>> is_prime(42)
False
>>> is_prime(41)
True
"""
# Check for small numbers.
if number < 10:
return number in {2, 3, 5, 7}
# Check for even numbers.
if not (number & 1):
return False
# Calculate minimum number of rounds.
k = get_primality_testing_rounds(number)
# Run primality testing with (minimum + 1) rounds.
return miller_rabin_primality_testing(number, k + 1)
def getprime(nbits: int) -> int:
"""Returns a prime number that can be stored in 'nbits' bits.
>>> p = getprime(128)
>>> is_prime(p-1)
False
>>> is_prime(p)
True
>>> is_prime(p+1)
False
>>> from rsa import common
>>> common.bit_size(p) == 128
True
"""
assert nbits > 3 # the loop wil hang on too small numbers
while True:
integer = rsa.randnum.read_random_odd_int(nbits)
# Test for primeness
if is_prime(integer):
return integer
# Retry if not prime
def are_relatively_prime(a: int, b: int) -> bool:
"""Returns True if a and b are relatively prime, and False if they
are not.
>>> are_relatively_prime(2, 3)
True
>>> are_relatively_prime(2, 4)
False
"""
d = gcd(a, b)
return d == 1
if __name__ == '__main__':
print('Running doctests 1000x or until failure')
import doctest
for count in range(1000):
(failures, tests) = doctest.testmod()
if failures:
break
if count % 100 == 0 and count:
print('%i times' % count)
print('Doctests done')

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# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Functions for generating random numbers."""
# Source inspired by code by Yesudeep Mangalapilly <yesudeep@gmail.com>
import os
import struct
from rsa import common, transform
def read_random_bits(nbits: int) -> bytes:
"""Reads 'nbits' random bits.
If nbits isn't a whole number of bytes, an extra byte will be appended with
only the lower bits set.
"""
nbytes, rbits = divmod(nbits, 8)
# Get the random bytes
randomdata = os.urandom(nbytes)
# Add the remaining random bits
if rbits > 0:
randomvalue = ord(os.urandom(1))
randomvalue >>= (8 - rbits)
randomdata = struct.pack("B", randomvalue) + randomdata
return randomdata
def read_random_int(nbits: int) -> int:
"""Reads a random integer of approximately nbits bits.
"""
randomdata = read_random_bits(nbits)
value = transform.bytes2int(randomdata)
# Ensure that the number is large enough to just fill out the required
# number of bits.
value |= 1 << (nbits - 1)
return value
def read_random_odd_int(nbits: int) -> int:
"""Reads a random odd integer of approximately nbits bits.
>>> read_random_odd_int(512) & 1
1
"""
value = read_random_int(nbits)
# Make sure it's odd
return value | 1
def randint(maxvalue: int) -> int:
"""Returns a random integer x with 1 <= x <= maxvalue
May take a very long time in specific situations. If maxvalue needs N bits
to store, the closer maxvalue is to (2 ** N) - 1, the faster this function
is.
"""
bit_size = common.bit_size(maxvalue)
tries = 0
while True:
value = read_random_int(bit_size)
if value <= maxvalue:
break
if tries % 10 == 0 and tries:
# After a lot of tries to get the right number of bits but still
# smaller than maxvalue, decrease the number of bits by 1. That'll
# dramatically increase the chances to get a large enough number.
bit_size -= 1
tries += 1
return value

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# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Data transformation functions.
From bytes to a number, number to bytes, etc.
"""
import math
def bytes2int(raw_bytes: bytes) -> int:
r"""Converts a list of bytes or an 8-bit string to an integer.
When using unicode strings, encode it to some encoding like UTF8 first.
>>> (((128 * 256) + 64) * 256) + 15
8405007
>>> bytes2int(b'\x80@\x0f')
8405007
"""
return int.from_bytes(raw_bytes, 'big', signed=False)
def int2bytes(number: int, fill_size: int = 0) -> bytes:
"""
Convert an unsigned integer to bytes (big-endian)::
Does not preserve leading zeros if you don't specify a fill size.
:param number:
Integer value
:param fill_size:
If the optional fill size is given the length of the resulting
byte string is expected to be the fill size and will be padded
with prefix zero bytes to satisfy that length.
:returns:
Raw bytes (base-256 representation).
:raises:
``OverflowError`` when fill_size is given and the number takes up more
bytes than fit into the block. This requires the ``overflow``
argument to this function to be set to ``False`` otherwise, no
error will be raised.
"""
if number < 0:
raise ValueError("Number must be an unsigned integer: %d" % number)
bytes_required = max(1, math.ceil(number.bit_length() / 8))
if fill_size > 0:
return number.to_bytes(fill_size, 'big')
return number.to_bytes(bytes_required, 'big')
if __name__ == '__main__':
import doctest
doctest.testmod()

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# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Utility functions."""
import sys
from optparse import OptionParser
import rsa.key
def private_to_public() -> None:
"""Reads a private key and outputs the corresponding public key."""
# Parse the CLI options
parser = OptionParser(usage='usage: %prog [options]',
description='Reads a private key and outputs the '
'corresponding public key. Both private and public keys use '
'the format described in PKCS#1 v1.5')
parser.add_option('-i', '--input', dest='infilename', type='string',
help='Input filename. Reads from stdin if not specified')
parser.add_option('-o', '--output', dest='outfilename', type='string',
help='Output filename. Writes to stdout of not specified')
parser.add_option('--inform', dest='inform',
help='key format of input - default PEM',
choices=('PEM', 'DER'), default='PEM')
parser.add_option('--outform', dest='outform',
help='key format of output - default PEM',
choices=('PEM', 'DER'), default='PEM')
(cli, cli_args) = parser.parse_args(sys.argv)
# Read the input data
if cli.infilename:
print('Reading private key from %s in %s format' %
(cli.infilename, cli.inform), file=sys.stderr)
with open(cli.infilename, 'rb') as infile:
in_data = infile.read()
else:
print('Reading private key from stdin in %s format' % cli.inform,
file=sys.stderr)
in_data = sys.stdin.read().encode('ascii')
assert type(in_data) == bytes, type(in_data)
# Take the public fields and create a public key
priv_key = rsa.key.PrivateKey.load_pkcs1(in_data, cli.inform)
pub_key = rsa.key.PublicKey(priv_key.n, priv_key.e)
# Save to the output file
out_data = pub_key.save_pkcs1(cli.outform)
if cli.outfilename:
print('Writing public key to %s in %s format' %
(cli.outfilename, cli.outform), file=sys.stderr)
with open(cli.outfilename, 'wb') as outfile:
outfile.write(out_data)
else:
print('Writing public key to stdout in %s format' % cli.outform,
file=sys.stderr)
sys.stdout.write(out_data.decode('ascii'))

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# -*- coding: utf-8 -*-
#
# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""VARBLOCK file support
.. deprecated:: 3.4
The VARBLOCK format is NOT recommended for general use, has been deprecated since
Python-RSA 3.4, and will be removed in a future release. It's vulnerable to a
number of attacks:
1. decrypt/encrypt_bigfile() does not implement `Authenticated encryption`_ nor
uses MACs to verify messages before decrypting public key encrypted messages.
2. decrypt/encrypt_bigfile() does not use hybrid encryption (it uses plain RSA)
and has no method for chaining, so block reordering is possible.
See `issue #19 on Github`_ for more information.
.. _Authenticated encryption: https://en.wikipedia.org/wiki/Authenticated_encryption
.. _issue #19 on Github: https://github.com/sybrenstuvel/python-rsa/issues/13
The VARBLOCK file format is as follows, where || denotes byte concatenation:
FILE := VERSION || BLOCK || BLOCK ...
BLOCK := LENGTH || DATA
LENGTH := varint-encoded length of the subsequent data. Varint comes from
Google Protobuf, and encodes an integer into a variable number of bytes.
Each byte uses the 7 lowest bits to encode the value. The highest bit set
to 1 indicates the next byte is also part of the varint. The last byte will
have this bit set to 0.
This file format is called the VARBLOCK format, in line with the varint format
used to denote the block sizes.
"""
import warnings
from rsa._compat import byte, b
ZERO_BYTE = b('\x00')
VARBLOCK_VERSION = 1
warnings.warn("The 'rsa.varblock' module was deprecated in Python-RSA version "
"3.4 due to security issues in the VARBLOCK format. See "
"https://github.com/sybrenstuvel/python-rsa/issues/13 for more information.",
DeprecationWarning)
def read_varint(infile):
"""Reads a varint from the file.
When the first byte to be read indicates EOF, (0, 0) is returned. When an
EOF occurs when at least one byte has been read, an EOFError exception is
raised.
:param infile: the file-like object to read from. It should have a read()
method.
:returns: (varint, length), the read varint and the number of read bytes.
"""
varint = 0
read_bytes = 0
while True:
char = infile.read(1)
if len(char) == 0:
if read_bytes == 0:
return 0, 0
raise EOFError('EOF while reading varint, value is %i so far' %
varint)
byte = ord(char)
varint += (byte & 0x7F) << (7 * read_bytes)
read_bytes += 1
if not byte & 0x80:
return varint, read_bytes
def write_varint(outfile, value):
"""Writes a varint to a file.
:param outfile: the file-like object to write to. It should have a write()
method.
:returns: the number of written bytes.
"""
# there is a big difference between 'write the value 0' (this case) and
# 'there is nothing left to write' (the false-case of the while loop)
if value == 0:
outfile.write(ZERO_BYTE)
return 1
written_bytes = 0
while value > 0:
to_write = value & 0x7f
value >>= 7
if value > 0:
to_write |= 0x80
outfile.write(byte(to_write))
written_bytes += 1
return written_bytes
def yield_varblocks(infile):
"""Generator, yields each block in the input file.
:param infile: file to read, is expected to have the VARBLOCK format as
described in the module's docstring.
@yields the contents of each block.
"""
# Check the version number
first_char = infile.read(1)
if len(first_char) == 0:
raise EOFError('Unable to read VARBLOCK version number')
version = ord(first_char)
if version != VARBLOCK_VERSION:
raise ValueError('VARBLOCK version %i not supported' % version)
while True:
(block_size, read_bytes) = read_varint(infile)
# EOF at block boundary, that's fine.
if read_bytes == 0 and block_size == 0:
break
block = infile.read(block_size)
read_size = len(block)
if read_size != block_size:
raise EOFError('Block size is %i, but could read only %i bytes' %
(block_size, read_size))
yield block
def yield_fixedblocks(infile, blocksize):
"""Generator, yields each block of ``blocksize`` bytes in the input file.
:param infile: file to read and separate in blocks.
:returns: a generator that yields the contents of each block
"""
while True:
block = infile.read(blocksize)
read_bytes = len(block)
if read_bytes == 0:
break
yield block
if read_bytes < blocksize:
break