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Vehicle-Anti-Theft-Face-Rec.../venv/Lib/site-packages/Crypto/PublicKey/DSA.py

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Updated DB_Helper by adding firebase methods.
2020-10-05 20:53:40 +00:00
# -*- coding: utf-8 -*-
#
# PublicKey/DSA.py : DSA signature primitive
#
# Written in 2008 by Dwayne C. Litzenberger <dlitz@dlitz.net>
#
# ===================================================================
# The contents of this file are dedicated to the public domain. To
# the extent that dedication to the public domain is not available,
# everyone is granted a worldwide, perpetual, royalty-free,
# non-exclusive license to exercise all rights associated with the
# contents of this file for any purpose whatsoever.
# No rights are reserved.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
# ===================================================================
"""DSA public-key signature algorithm.
DSA_ is a widespread public-key signature algorithm. Its security is
based on the discrete logarithm problem (DLP_). Given a cyclic
group, a generator *g*, and an element *h*, it is hard
to find an integer *x* such that *g^x = h*. The problem is believed
to be difficult, and it has been proved such (and therefore secure) for
more than 30 years.
The group is actually a sub-group over the integers modulo *p*, with *p* prime.
The sub-group order is *q*, which is prime too; it always holds that *(p-1)* is a multiple of *q*.
The cryptographic strength is linked to the magnitude of *p* and *q*.
The signer holds a value *x* (*0<x<q-1*) as private key, and its public
key (*y* where *y=g^x mod p*) is distributed.
In 2012, a sufficient size is deemed to be 2048 bits for *p* and 256 bits for *q*.
For more information, see the most recent ECRYPT_ report.
DSA is reasonably secure for new designs.
The algorithm can only be used for authentication (digital signature).
DSA cannot be used for confidentiality (encryption).
The values *(p,q,g)* are called *domain parameters*;
they are not sensitive but must be shared by both parties (the signer and the verifier).
Different signers can share the same domain parameters with no security
concerns.
The DSA signature is twice as big as the size of *q* (64 bytes if *q* is 256 bit
long).
This module provides facilities for generating new DSA keys and for constructing
them from known components. DSA keys allows you to perform basic signing and
verification.
>>> from Crypto.PublicKey import DSA
>>> from Crypto.Signature.DSS
>>> from Crypto.Hash import SHA256
>>>
>>> message = b"Hello"
>>> key = DSA.generate(2048)
>>> f = open("public_key.pem", "w")
>>> f.write(key.publickey().exportKey(key))
>>> hash_obj = SHA256.new(message)
>>> signer = DSS.new(key, 'fips-186-3')
>>> signature = key.sign(hash_obj)
>>> ...
>>> f = open("public_key.pem", "r")
>>> hash_obj = SHA256.new(message)
>>> pub_key = DSA.import_key(f.read())
>>> if pub_key.verify(hash_obj, signature):
>>> print "OK"
>>> else:
>>> print "Incorrect signature"
.. _DSA: http://en.wikipedia.org/wiki/Digital_Signature_Algorithm
.. _DLP: http://www.cosic.esat.kuleuven.be/publications/talk-78.pdf
.. _ECRYPT: http://www.ecrypt.eu.org/documents/D.SPA.17.pdf
"""
__all__ = ['generate', 'construct', 'DSAImplementation',
'DsaKey', 'import_key' ]
import binascii
import struct
import itertools
from Crypto.Util.py3compat import *
from Crypto import Random
from Crypto.IO import PKCS8, PEM
from Crypto.Hash import SHA256
from Crypto.Util.asn1 import (
DerObject, DerSequence,
DerInteger, DerObjectId,
DerBitString,
)
from Crypto.Math.Numbers import Integer
from Crypto.Math.Primality import (test_probable_prime, COMPOSITE,
PROBABLY_PRIME)
from Crypto.PublicKey import (_expand_subject_public_key_info,
_create_subject_public_key_info,
_extract_subject_public_key_info)
# ; The following ASN.1 types are relevant for DSA
#
# SubjectPublicKeyInfo ::= SEQUENCE {
# algorithm AlgorithmIdentifier,
# subjectPublicKey BIT STRING
# }
#
# id-dsa ID ::= { iso(1) member-body(2) us(840) x9-57(10040) x9cm(4) 1 }
#
# ; See RFC3279
# Dss-Parms ::= SEQUENCE {
# p INTEGER,
# q INTEGER,
# g INTEGER
# }
#
# DSAPublicKey ::= INTEGER
#
# DSSPrivatKey_OpenSSL ::= SEQUENCE
# version INTEGER,
# p INTEGER,
# q INTEGER,
# g INTEGER,
# y INTEGER,
# x INTEGER
# }
#
class DsaKey(object):
"""Class defining an actual DSA key.
:undocumented: __getstate__, __setstate__, __repr__, __getattr__,
__init__, __eq__, __ne__, sign, verify, encrypt, decrypt,
blind, unblind, size
"""
#: Dictionary of DSA parameters.
#:
#: A public key will only have the following entries:
#:
#: - **y**, the public key.
#: - **g**, the generator.
#: - **p**, the modulus.
#: - **q**, the order of the sub-group.
#:
#: A private key will also have:
#:
#: - **x**, the private key.
_keydata = ['y', 'g', 'p', 'q', 'x']
def __init__(self, key_dict):
input_set = set(key_dict.keys())
public_set = set(('y' , 'g', 'p', 'q'))
if not public_set.issubset(input_set):
raise ValueError("Some DSA components are missing = %s" %
str(public_set - input_set))
extra_set = input_set - public_set
if extra_set and extra_set != set(('x',)):
raise ValueError("Unknown DSA components = %s" %
str(extra_set - set(('x',))))
self._key = dict(key_dict)
def _sign(self, m, k):
if not self.has_private():
raise TypeError("DSA public key cannot be used for signing")
if not (1 < k < self.q):
raise ValueError("k is not between 2 and q-1")
x, q, p, g = [self._key[comp] for comp in ['x', 'q', 'p', 'g']]
blind_factor = Integer.random_range(min_inclusive=1,
max_exclusive=q)
inv_blind_k = (blind_factor * k).inverse(q)
blind_x = x * blind_factor
r = pow(g, k, p) % q # r = (g**k mod p) mod q
s = (inv_blind_k * (blind_factor * m + blind_x * r)) % q
return list(map(int, (r, s)))
def _verify(self, m, sig):
r, s = sig
y, q, p, g = [self._key[comp] for comp in ['y', 'q', 'p', 'g']]
if not (0 < r < q) or not (0 < s < q):
return False
w = Integer(s).inverse(q)
u1 = (w * m) % q
u2 = (w * r) % q
v = (pow(g, u1, p) * pow(y, u2, p) % p) % q
return v == r
def has_private(self):
return 'x' in self._key
def can_encrypt(self):
return False
def can_sign(self):
return True
def publickey(self):
public_components = dict((k, self._key[k]) for k in ('y', 'g', 'p', 'q'))
return DsaKey(public_components)
def __eq__(self, other):
if bool(self.has_private()) != bool(other.has_private()):
return False
result = True
for comp in self._keydata:
result = result and (getattr(self._key, comp, None) ==
getattr(other._key, comp, None))
return result
def __ne__(self, other):
return not self.__eq__(other)
def __getstate__(self):
# DSA key is not pickable
from pickle import PicklingError
raise PicklingError
def domain(self):
"""The DSA domain parameters: *p*, *q* and *g*. """
return list(map(int, [self._key[comp] for comp in ('p', 'q', 'g')]))
def __repr__(self):
attrs = []
for k in self._keydata:
if k == 'p':
attrs.append("p(%d)" % (self.size()+1,))
elif hasattr(self, k):
attrs.append(k)
if self.has_private():
attrs.append("private")
# PY3K: This is meant to be text, do not change to bytes (data)
return "<%s @0x%x %s>" % (self.__class__.__name__, id(self), ",".join(attrs))
def __getattr__(self, item):
try:
return int(self._key[item])
except KeyError:
raise AttributeError(item)
def exportKey(self, format='PEM', pkcs8=None, passphrase=None,
protection=None, randfunc=None):
"""Export this DSA key.
:Parameters:
format : string
The format to use for wrapping the key:
- *'DER'*. Binary encoding.
- *'PEM'*. Textual encoding, done according to `RFC1421`_/
`RFC1423`_ (default).
- *'OpenSSH'*. Textual encoding, one line of text, see `RFC4253`_.
Only suitable for public keys, not private keys.
passphrase : string
For private keys only. The pass phrase to use for deriving
the encryption key.
pkcs8 : boolean
For private keys only. If ``True`` (default), the key is arranged
according to `PKCS#8`_ and if `False`, according to the custom
OpenSSL/OpenSSH encoding.
protection : string
The encryption scheme to use for protecting the private key.
It is only meaningful when a pass phrase is present too.
If ``pkcs8`` takes value ``True``, ``protection`` is the PKCS#8
algorithm to use for deriving the secret and encrypting
the private DSA key.
For a complete list of algorithms, see `Crypto.IO.PKCS8`.
The default is *PBKDF2WithHMAC-SHA1AndDES-EDE3-CBC*.
If ``pkcs8`` is ``False``, the obsolete PEM encryption scheme is
used. It is based on MD5 for key derivation, and Triple DES for
encryption. Parameter ``protection`` is ignored.
The combination ``format='DER'`` and ``pkcs8=False`` is not allowed
if a passphrase is present.
randfunc : callable
A function that returns random bytes.
By default it is `Crypto.Random.get_random_bytes`.
:Return: A byte string with the encoded public or private half
of the key.
:Raise ValueError:
When the format is unknown or when you try to encrypt a private
key with *DER* format and OpenSSL/OpenSSH.
:attention:
If you don't provide a pass phrase, the private key will be
exported in the clear!
.. _RFC1421: http://www.ietf.org/rfc/rfc1421.txt
.. _RFC1423: http://www.ietf.org/rfc/rfc1423.txt
.. _RFC4253: http://www.ietf.org/rfc/rfc4253.txt
.. _`PKCS#8`: http://www.ietf.org/rfc/rfc5208.txt
"""
if passphrase is not None:
passphrase = tobytes(passphrase)
if randfunc is None:
randfunc = Random.get_random_bytes
if format == 'OpenSSH':
tup1 = [self._key[x].to_bytes() for x in ('p', 'q', 'g', 'y')]
def func(x):
if (bord(x[0]) & 0x80):
return bchr(0) + x
else:
return x
tup2 = list(map(func, tup1))
keyparts = [b('ssh-dss')] + tup2
keystring = b('').join(
[struct.pack(">I", len(kp)) + kp for kp in keyparts]
)
return b('ssh-dss ') + binascii.b2a_base64(keystring)[:-1]
# DER format is always used, even in case of PEM, which simply
# encodes it into BASE64.
params = DerSequence([self.p, self.q, self.g])
if self.has_private():
if pkcs8 is None:
pkcs8 = True
if pkcs8:
if not protection:
protection = 'PBKDF2WithHMAC-SHA1AndDES-EDE3-CBC'
private_key = DerInteger(self.x).encode()
binary_key = PKCS8.wrap(
private_key, oid, passphrase,
protection, key_params=params,
randfunc=randfunc
)
if passphrase:
key_type = 'ENCRYPTED PRIVATE'
else:
key_type = 'PRIVATE'
passphrase = None
else:
if format != 'PEM' and passphrase:
raise ValueError("DSA private key cannot be encrypted")
ints = [0, self.p, self.q, self.g, self.y, self.x]
binary_key = DerSequence(ints).encode()
key_type = "DSA PRIVATE"
else:
if pkcs8:
raise ValueError("PKCS#8 is only meaningful for private keys")
binary_key = _create_subject_public_key_info(oid,
DerInteger(self.y), params)
key_type = "DSA PUBLIC"
if format == 'DER':
return binary_key
if format == 'PEM':
pem_str = PEM.encode(
binary_key, key_type + " KEY",
passphrase, randfunc
)
return tobytes(pem_str)
raise ValueError("Unknown key format '%s'. Cannot export the DSA key." % format)
# Methods defined in PyCrypto that we don't support anymore
def sign(self, M, K):
raise NotImplementedError("Use module Crypto.Signature.DSS instead")
def verify(self, M, signature):
raise NotImplementedError("Use module Crypto.Signature.DSS instead")
def encrypt(self, plaintext, K):
raise NotImplementedError
def decrypt(self, ciphertext):
raise NotImplementedError
def blind(self, M, B):
raise NotImplementedError
def unblind(self, M, B):
raise NotImplementedError
def size():
raise NotImplementedError
def _generate_domain(L, randfunc):
"""Generate a new set of DSA domain parameters"""
N = { 1024:160, 2048:224, 3072:256 }.get(L)
if N is None:
raise ValueError("Invalid modulus length (%d)" % L)
outlen = SHA256.digest_size * 8
n = (L + outlen - 1) // outlen - 1 # ceil(L/outlen) -1
b_ = L - 1 - (n * outlen)
# Generate q (A.1.1.2)
q = Integer(4)
upper_bit = 1 << (N - 1)
while test_probable_prime(q, randfunc) != PROBABLY_PRIME:
seed = randfunc(64)
U = Integer.from_bytes(SHA256.new(seed).digest()) & (upper_bit - 1)
q = U | upper_bit | 1
assert(q.size_in_bits() == N)
# Generate p (A.1.1.2)
offset = 1
upper_bit = 1 << (L - 1)
while True:
V = [ SHA256.new(seed + Integer(offset + j).to_bytes()).digest()
for j in range(n + 1) ]
V = [ Integer.from_bytes(v) for v in V ]
W = sum([V[i] * (1 << (i * outlen)) for i in range(n)],
(V[n] & (1 << b_ - 1)) * (1 << (n * outlen)))
X = Integer(W + upper_bit) # 2^{L-1} < X < 2^{L}
assert(X.size_in_bits() == L)
c = X % (q * 2)
p = X - (c - 1) # 2q divides (p-1)
if p.size_in_bits() == L and \
test_probable_prime(p, randfunc) == PROBABLY_PRIME:
break
offset += n + 1
# Generate g (A.2.3, index=1)
e = (p - 1) // q
for count in itertools.count(1):
U = seed + b("ggen") + bchr(1) + Integer(count).to_bytes()
W = Integer.from_bytes(SHA256.new(U).digest())
g = pow(W, e, p)
if g != 1:
break
return (p, q, g, seed)
def generate(bits, randfunc=None, domain=None):
"""Generate a new DSA key pair.
The algorithm follows Appendix A.1/A.2 and B.1 of `FIPS 186-4`_,
respectively for domain generation and key pair generation.
:Parameters:
bits : integer
Key length, or size (in bits) of the DSA modulus *p*.
It must be 1024, 2048 or 3072.
randfunc : callable
Random number generation function; it accepts a single integer N
and return a string of random data N bytes long.
If not specified, the default from ``Crypto.Random`` is used.
domain : list
The DSA domain parameters *p*, *q* and *g* as a list of 3
integers. Size of *p* and *q* must comply to `FIPS 186-4`_.
If not specified, the parameters are created anew.
:Return: A DSA key object (`DsaKey`).
:Raise ValueError:
When **bits** is too little, too big, or not a multiple of 64.
.. _FIPS 186-4: http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-4.pdf
"""
if randfunc is None:
randfunc = Random.get_random_bytes
if domain:
p, q, g = list(map(Integer, domain))
## Perform consistency check on domain parameters
# P and Q must be prime
fmt_error = test_probable_prime(p) == COMPOSITE
fmt_error = test_probable_prime(q) == COMPOSITE
# Verify Lagrange's theorem for sub-group
fmt_error |= ((p - 1) % q) != 0
fmt_error |= g <= 1 or g >= p
fmt_error |= pow(g, q, p) != 1
if fmt_error:
raise ValueError("Invalid DSA domain parameters")
else:
p, q, g, _ = _generate_domain(bits, randfunc)
L = p.size_in_bits()
N = q.size_in_bits()
if L != bits:
raise ValueError("Mismatch between size of modulus (%d)"
" and 'bits' parameter (%d)" % (L, bits))
if (L, N) not in [(1024, 160), (2048, 224),
(2048, 256), (3072, 256)]:
raise ValueError("Lengths of p and q (%d, %d) are not compatible"
"to FIPS 186-3" % (L, N))
if not 1 < g < p:
raise ValueError("Incorrent DSA generator")
# B.1.1
c = Integer.random(exact_bits=N + 64)
x = c % (q - 1) + 1 # 1 <= x <= q-1
y = pow(g, x, p)
key_dict = { 'y':y, 'g':g, 'p':p, 'q':q, 'x':x }
return DsaKey(key_dict)
def construct(tup, consistency_check=True):
"""Construct a DSA key from a tuple of valid DSA components.
:Parameters:
tup : tuple
A tuple of long integers, with 4 or 5 items
in the following order:
1. Public key (*y*).
2. Sub-group generator (*g*).
3. Modulus, finite field order (*p*).
4. Sub-group order (*q*).
5. Private key (*x*). Optional.
consistency_check : boolean
If *True*, the library will verify that the provided components
fulfil the main DSA properties.
:Raise PublicKey.ValueError:
When the key being imported fails the most basic DSA validity checks.
:Return: A DSA key object (`DsaKey`).
"""
key_dict = dict(list(zip(('y', 'g', 'p', 'q', 'x'), list(map(Integer, tup)))))
key = DsaKey(key_dict)
fmt_error = False
if consistency_check:
# P and Q must be prime
fmt_error = test_probable_prime(key.p) == COMPOSITE
fmt_error = test_probable_prime(key.q) == COMPOSITE
# Verify Lagrange's theorem for sub-group
fmt_error |= ((key.p - 1) % key.q) != 0
fmt_error |= key.g <= 1 or key.g >= key.p
fmt_error |= pow(key.g, key.q, key.p) != 1
# Public key
fmt_error |= key.y <= 0 or key.y >= key.p
if hasattr(key, 'x'):
fmt_error |= key.x <= 0 or key.x >= key.q
fmt_error |= pow(key.g, key.x, key.p) != key.y
if fmt_error:
raise ValueError("Invalid DSA key components")
return key
# Dss-Parms ::= SEQUENCE {
# p OCTET STRING,
# q OCTET STRING,
# g OCTET STRING
# }
# DSAPublicKey ::= INTEGER -- public key, y
def _import_openssl_private(encoded, passphrase, params):
if params:
raise ValueError("DSA private key already comes with parameters")
der = DerSequence().decode(encoded, nr_elements=6, only_ints_expected=True)
if der[0] != 0:
raise ValueError("No version found")
tup = [der[comp] for comp in (4, 3, 1, 2, 5)]
return construct(tup)
def _import_subjectPublicKeyInfo(encoded, passphrase, params):
algoid, encoded_key, emb_params = _expand_subject_public_key_info(encoded)
if algoid != oid:
raise ValueError("No DSA subjectPublicKeyInfo")
if params and emb_params:
raise ValueError("Too many DSA parameters")
y = DerInteger().decode(encoded_key).value
p, q, g = list(DerSequence().decode(params or emb_params))
tup = (y, g, p, q)
return construct(tup)
def _import_x509_cert(encoded, passphrase, params):
sp_info = _extract_subject_public_key_info(encoded)
return _import_subjectPublicKeyInfo(sp_info, None, params)
def _import_pkcs8(encoded, passphrase, params):
if params:
raise ValueError("PKCS#8 already includes parameters")
k = PKCS8.unwrap(encoded, passphrase)
if k[0] != oid:
raise ValueError("No PKCS#8 encoded DSA key")
x = DerInteger().decode(k[1]).value
p, q, g = list(DerSequence().decode(k[2]))
tup = (pow(g, x, p), g, p, q, x)
return construct(tup)
def _import_key_der(key_data, passphrase, params):
"""Import a DSA key (public or private half), encoded in DER form."""
decodings = (_import_openssl_private,
_import_subjectPublicKeyInfo,
_import_x509_cert,
_import_pkcs8)
for decoding in decodings:
try:
return decoding(key_data, passphrase, params)
except ValueError:
pass
raise ValueError("DSA key format is not supported")
def import_key(extern_key, passphrase=None):
"""Import a DSA key (public or private).
:Parameters:
extern_key : (byte) string
The DSA key to import.
An DSA *public* key can be in any of the following formats:
- X.509 certificate (binary or PEM format)
- X.509 ``subjectPublicKeyInfo`` (binary or PEM)
- OpenSSH (one line of text, see `RFC4253`_)
A DSA *private* key can be in any of the following formats:
- `PKCS#8`_ ``PrivateKeyInfo`` or ``EncryptedPrivateKeyInfo``
DER SEQUENCE (binary or PEM encoding)
- OpenSSL/OpenSSH (binary or PEM)
For details about the PEM encoding, see `RFC1421`_/`RFC1423`_.
The private key may be encrypted by means of a certain pass phrase
either at the PEM level or at the PKCS#8 level.
passphrase : string
In case of an encrypted private key, this is the pass phrase
from which the decryption key is derived.
:Return: A DSA key object (`DsaKey`).
:Raise ValueError:
When the given key cannot be parsed (possibly because
the pass phrase is wrong).
.. _RFC1421: http://www.ietf.org/rfc/rfc1421.txt
.. _RFC1423: http://www.ietf.org/rfc/rfc1423.txt
.. _RFC4253: http://www.ietf.org/rfc/rfc4253.txt
.. _PKCS#8: http://www.ietf.org/rfc/rfc5208.txt
"""
extern_key = tobytes(extern_key)
if passphrase is not None:
passphrase = tobytes(passphrase)
if extern_key.startswith(b('-----')):
# This is probably a PEM encoded key
(der, marker, enc_flag) = PEM.decode(tostr(extern_key), passphrase)
if enc_flag:
passphrase = None
return _import_key_der(der, passphrase, None)
if extern_key.startswith(b('ssh-dss ')):
# This is probably a public OpenSSH key
keystring = binascii.a2b_base64(extern_key.split(b(' '))[1])
keyparts = []
while len(keystring) > 4:
length = struct.unpack(">I", keystring[:4])[0]
keyparts.append(keystring[4:4 + length])
keystring = keystring[4 + length:]
if keyparts[0] == b("ssh-dss"):
tup = [Integer.from_bytes(keyparts[x]) for x in (4, 3, 1, 2)]
return construct(tup)
if bord(extern_key[0]) == 0x30:
# This is probably a DER encoded key
return _import_key_der(extern_key, passphrase, None)
raise ValueError("DSA key format is not supported")
# Backward compatibility
importKey = import_key
#: `Object ID`_ for a DSA key.
#:
#: id-dsa ID ::= { iso(1) member-body(2) us(840) x9-57(10040) x9cm(4) 1 }
#:
#: .. _`Object ID`: http://www.alvestrand.no/objectid/1.2.840.10040.4.1.html
oid = "1.2.840.10040.4.1"
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