103 lines
3.4 KiB
Python
103 lines
3.4 KiB
Python
# -*- coding: utf-8 -*-
|
|
#
|
|
# ===================================================================
|
|
# 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.
|
|
# ===================================================================
|
|
|
|
"""Public-key encryption and signature algorithms.
|
|
|
|
Public-key encryption uses two different keys, one for encryption and
|
|
one for decryption. The encryption key can be made public, and the
|
|
decryption key is kept private. Many public-key algorithms can also
|
|
be used to sign messages, and some can *only* be used for signatures.
|
|
"""
|
|
|
|
from Crypto.Util.asn1 import (DerSequence, DerInteger, DerBitString,
|
|
DerObjectId, DerNull)
|
|
|
|
|
|
def _expand_subject_public_key_info(encoded):
|
|
"""Parse a SubjectPublicKeyInfo structure.
|
|
|
|
It returns a triple with:
|
|
* OID (string)
|
|
* encoded public key (bytes)
|
|
* Algorithm parameters (bytes or None)
|
|
"""
|
|
|
|
#
|
|
# SubjectPublicKeyInfo ::= SEQUENCE {
|
|
# algorithm AlgorithmIdentifier,
|
|
# subjectPublicKey BIT STRING
|
|
# }
|
|
#
|
|
# AlgorithmIdentifier ::= SEQUENCE {
|
|
# algorithm OBJECT IDENTIFIER,
|
|
# parameters ANY DEFINED BY algorithm OPTIONAL
|
|
# }
|
|
#
|
|
|
|
spki = DerSequence().decode(encoded, nr_elements=2)
|
|
algo = DerSequence().decode(spki[0], nr_elements=(1,2))
|
|
algo_oid = DerObjectId().decode(algo[0])
|
|
spk = DerBitString().decode(spki[1]).value
|
|
|
|
if len(algo) == 1:
|
|
algo_params = None
|
|
else:
|
|
try:
|
|
DerNull().decode(algo[1])
|
|
algo_params = None
|
|
except:
|
|
algo_params = algo[1]
|
|
|
|
return algo_oid.value, spk, algo_params
|
|
|
|
|
|
def _create_subject_public_key_info(algo_oid, secret_key, params=None):
|
|
|
|
if params is None:
|
|
params = DerNull()
|
|
|
|
spki = DerSequence([
|
|
DerSequence([
|
|
DerObjectId(algo_oid),
|
|
params]),
|
|
DerBitString(secret_key)
|
|
])
|
|
return spki.encode()
|
|
|
|
|
|
def _extract_subject_public_key_info(x509_certificate):
|
|
"""Extract subjectPublicKeyInfo from a DER X.509 certificate."""
|
|
|
|
certificate = DerSequence().decode(x509_certificate, nr_elements=3)
|
|
tbs_certificate = DerSequence().decode(certificate[0],
|
|
nr_elements=list(range(6, 11)))
|
|
|
|
index = 5
|
|
try:
|
|
tbs_certificate[0] + 1
|
|
# Version not present
|
|
version = 1
|
|
except TypeError:
|
|
version = DerInteger(explicit=0).decode(tbs_certificate[0]).value
|
|
if version not in (2, 3):
|
|
raise ValueError("Incorrect X.509 certificate version")
|
|
index = 6
|
|
|
|
return tbs_certificate[index]
|