# -*- 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. # =================================================================== 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, public_key, params): if params is None: algorithm = DerSequence([DerObjectId(algo_oid)]) else: algorithm = DerSequence([DerObjectId(algo_oid), params]) spki = DerSequence([algorithm, DerBitString(public_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=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]