227 lines
7.6 KiB
Python
227 lines
7.6 KiB
Python
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#
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# PublicKey/PKCS8.py : PKCS#8 functions
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#
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# ===================================================================
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#
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# Copyright (c) 2014, Legrandin <helderijs@gmail.com>
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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#
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# 1. Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in
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# the documentation and/or other materials provided with the
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# distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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# COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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# POSSIBILITY OF SUCH DAMAGE.
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# ===================================================================
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from Cryptodome.Util.py3compat import *
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from Cryptodome.Util.asn1 import (
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DerNull,
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DerSequence,
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DerObjectId,
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DerOctetString,
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)
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from Cryptodome.IO._PBES import PBES1, PBES2, PbesError
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__all__ = ['wrap', 'unwrap']
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def wrap(private_key, key_oid, passphrase=None, protection=None,
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prot_params=None, key_params=DerNull(), randfunc=None):
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"""Wrap a private key into a PKCS#8 blob (clear or encrypted).
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Args:
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private_key (bytes):
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The private key encoded in binary form. The actual encoding is
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algorithm specific. In most cases, it is DER.
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key_oid (string):
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The object identifier (OID) of the private key to wrap.
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It is a dotted string, like ``'1.2.840.113549.1.1.1'`` (for RSA keys)
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or ``'1.2.840.10045.2.1'`` (for ECC keys).
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Keyword Args:
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passphrase (bytes or string):
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The secret passphrase from which the wrapping key is derived.
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Set it only if encryption is required.
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protection (string):
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The identifier of the algorithm to use for securely wrapping the key.
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Refer to :ref:`the encryption parameters<enc_params>` .
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The default value is ``'PBKDF2WithHMAC-SHA1AndDES-EDE3-CBC'``.
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prot_params (dictionary):
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Parameters for the key derivation function (KDF).
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Refer to :ref:`the encryption parameters<enc_params>` .
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key_params (DER object or None):
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The ``parameters`` field to use in the ``AlgorithmIdentifier``
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SEQUENCE. If ``None``, no ``parameters`` field will be added.
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By default, the ASN.1 type ``NULL`` is used.
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randfunc (callable):
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Random number generation function; it should accept a single integer
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N and return a string of random data, N bytes long.
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If not specified, a new RNG will be instantiated
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from :mod:`Cryptodome.Random`.
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Returns:
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bytes: The PKCS#8-wrapped private key (possibly encrypted).
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"""
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#
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# PrivateKeyInfo ::= SEQUENCE {
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# version Version,
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# privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
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# privateKey PrivateKey,
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# attributes [0] IMPLICIT Attributes OPTIONAL
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# }
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#
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if key_params is None:
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algorithm = DerSequence([DerObjectId(key_oid)])
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else:
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algorithm = DerSequence([DerObjectId(key_oid), key_params])
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pk_info = DerSequence([
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0,
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algorithm,
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DerOctetString(private_key)
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])
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pk_info_der = pk_info.encode()
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if passphrase is None:
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return pk_info_der
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if not passphrase:
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raise ValueError("Empty passphrase")
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# Encryption with PBES2
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passphrase = tobytes(passphrase)
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if protection is None:
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protection = 'PBKDF2WithHMAC-SHA1AndDES-EDE3-CBC'
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return PBES2.encrypt(pk_info_der, passphrase,
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protection, prot_params, randfunc)
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def unwrap(p8_private_key, passphrase=None):
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"""Unwrap a private key from a PKCS#8 blob (clear or encrypted).
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Args:
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p8_private_key (bytes):
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The private key wrapped into a PKCS#8 container, DER encoded.
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Keyword Args:
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passphrase (byte string or string):
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The passphrase to use to decrypt the blob (if it is encrypted).
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Return:
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A tuple containing
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#. the algorithm identifier of the wrapped key (OID, dotted string)
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#. the private key (bytes, DER encoded)
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#. the associated parameters (bytes, DER encoded) or ``None``
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Raises:
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ValueError : if decoding fails
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"""
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if passphrase:
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passphrase = tobytes(passphrase)
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found = False
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try:
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p8_private_key = PBES1.decrypt(p8_private_key, passphrase)
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found = True
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except PbesError as e:
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error_str = "PBES1[%s]" % str(e)
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except ValueError:
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error_str = "PBES1[Invalid]"
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if not found:
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try:
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p8_private_key = PBES2.decrypt(p8_private_key, passphrase)
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found = True
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except PbesError as e:
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error_str += ",PBES2[%s]" % str(e)
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except ValueError:
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error_str += ",PBES2[Invalid]"
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if not found:
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raise ValueError("Error decoding PKCS#8 (%s)" % error_str)
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pk_info = DerSequence().decode(p8_private_key, nr_elements=(2, 3, 4, 5))
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if len(pk_info) == 2 and not passphrase:
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raise ValueError("Not a valid clear PKCS#8 structure "
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"(maybe it is encrypted?)")
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# RFC5208, PKCS#8, version is v1(0)
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#
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# PrivateKeyInfo ::= SEQUENCE {
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# version Version,
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# privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
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# privateKey PrivateKey,
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# attributes [0] IMPLICIT Attributes OPTIONAL
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# }
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#
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# RFC5915, Asymmetric Key Package, version is v2(1)
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#
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# OneAsymmetricKey ::= SEQUENCE {
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# version Version,
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# privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
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# privateKey PrivateKey,
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# attributes [0] Attributes OPTIONAL,
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# ...,
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# [[2: publicKey [1] PublicKey OPTIONAL ]],
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# ...
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# }
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if pk_info[0] == 0:
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if len(pk_info) not in (3, 4):
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raise ValueError("Not a valid PrivateKeyInfo SEQUENCE")
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elif pk_info[0] == 1:
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if len(pk_info) not in (3, 4, 5):
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raise ValueError("Not a valid PrivateKeyInfo SEQUENCE")
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else:
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raise ValueError("Not a valid PrivateKeyInfo SEQUENCE")
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algo = DerSequence().decode(pk_info[1], nr_elements=(1, 2))
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algo_oid = DerObjectId().decode(algo[0]).value
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if len(algo) == 1:
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algo_params = None
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else:
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try:
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DerNull().decode(algo[1])
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algo_params = None
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except:
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algo_params = algo[1]
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# PrivateKey ::= OCTET STRING
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private_key = DerOctetString().decode(pk_info[2]).payload
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# We ignore attributes and (for v2 only) publickey
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return (algo_oid, private_key, algo_params)
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