/usr/lib/python3/dist-packages/asyncssh/dsa.py is in python3-asyncssh 1.3.0-1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 | # Copyright (c) 2013-2015 by Ron Frederick <ronf@timeheart.net>.
# All rights reserved.
#
# This program and the accompanying materials are made available under
# the terms of the Eclipse Public License v1.0 which accompanies this
# distribution and is available at:
#
# http://www.eclipse.org/legal/epl-v10.html
#
# Contributors:
# Ron Frederick - initial implementation, API, and documentation
"""DSA public key encryption handler"""
from .asn1 import ASN1DecodeError, ObjectIdentifier, der_encode, der_decode
from .crypto import DSAPrivateKey, DSAPublicKey
from .misc import all_ints
from .packet import MPInt, String, PacketDecodeError, SSHPacket
from .public_key import SSHKey, SSHCertificateV00, SSHCertificateV01
from .public_key import KeyExportError
from .public_key import register_public_key_alg, register_certificate_alg
# Short variable names are used here, matching names in the spec
# pylint: disable=invalid-name
class _DSAKey(SSHKey):
"""Handler for DSA public key encryption"""
algorithm = b'ssh-dss'
pem_name = b'DSA'
pkcs8_oid = ObjectIdentifier('1.2.840.10040.4.1')
def __init__(self, key):
self._key = key
def __eq__(self, other):
# This isn't protected access - both objects are _DSAKey instances
# pylint: disable=protected-access
return (isinstance(other, self.__class__) and
self._key.p == other._key.p and
self._key.q == other._key.q and
self._key.g == other._key.g and
self._key.y == other._key.y and
self._key.x == other._key.x)
def __hash__(self):
return hash((self._key.p, self._key.q, self._key.g,
self._key.y, self._key.x))
@classmethod
def make_private(cls, *args):
"""Construct a DSA private key"""
return cls(DSAPrivateKey(*args))
@classmethod
def make_public(cls, *args):
"""Construct a DSA public key"""
return cls(DSAPublicKey(*args))
@classmethod
def decode_pkcs1_private(cls, key_data):
"""Decode a PKCS#1 format DSA private key"""
if (isinstance(key_data, tuple) and len(key_data) == 6 and
all_ints(key_data) and key_data[0] == 0):
return key_data[1:]
else:
return None
@classmethod
def decode_pkcs1_public(cls, key_data):
"""Decode a PKCS#1 format DSA public key"""
if (isinstance(key_data, tuple) and len(key_data) == 4 and
all_ints(key_data)):
y, p, q, g = key_data
return p, q, g, y
else:
return None
@classmethod
def decode_pkcs8_private(cls, alg_params, data):
"""Decode a PKCS#8 format DSA private key"""
try:
x = der_decode(data)
except ASN1DecodeError:
return None
if (isinstance(alg_params, tuple) and len(alg_params) == 3 and
all_ints(alg_params) and isinstance(x, int)):
p, q, g = alg_params
y = pow(g, x, p)
return p, q, g, y, x
else:
return None
@classmethod
def decode_pkcs8_public(cls, alg_params, data):
"""Decode a PKCS#8 format DSA public key"""
try:
y = der_decode(data)
except ASN1DecodeError:
return None
if (isinstance(alg_params, tuple) and len(alg_params) == 3 and
all_ints(alg_params) and isinstance(y, int)):
p, q, g = alg_params
return p, q, g, y
else:
return None
@classmethod
def decode_ssh_private(cls, packet):
"""Decode an SSH format DSA private key"""
p = packet.get_mpint()
q = packet.get_mpint()
g = packet.get_mpint()
y = packet.get_mpint()
x = packet.get_mpint()
return p, q, g, y, x
@classmethod
def decode_ssh_public(cls, packet):
"""Decode an SSH format DSA public key"""
p = packet.get_mpint()
q = packet.get_mpint()
g = packet.get_mpint()
y = packet.get_mpint()
return p, q, g, y
def encode_pkcs1_private(self):
"""Encode a PKCS#1 format DSA private key"""
if not self._key.x:
raise KeyExportError('Key is not private')
return (0, self._key.p, self._key.q, self._key.g,
self._key.y, self._key.x)
def encode_pkcs1_public(self):
"""Encode a PKCS#1 format DSA public key"""
return (self._key.y, self._key.p, self._key.q, self._key.g)
def encode_pkcs8_private(self):
"""Encode a PKCS#8 format DSA private key"""
if not self._key.x:
raise KeyExportError('Key is not private')
return (self._key.p, self._key.q, self._key.g), der_encode(self._key.x)
def encode_pkcs8_public(self):
"""Encode a PKCS#8 format DSA public key"""
return (self._key.p, self._key.q, self._key.g), der_encode(self._key.y)
def encode_ssh_private(self):
"""Encode an SSH format DSA private key"""
if not self._key.x:
raise KeyExportError('Key is not private')
return b''.join((MPInt(self._key.p), MPInt(self._key.q),
MPInt(self._key.g), MPInt(self._key.y),
MPInt(self._key.x)))
def encode_ssh_public(self):
"""Encode an SSH format DSA public key"""
return b''.join((MPInt(self._key.p), MPInt(self._key.q),
MPInt(self._key.g), MPInt(self._key.y)))
def sign(self, data):
"""Return a signature of the specified data using this key"""
if not self._key.x:
raise ValueError('Private key needed for signing')
r, s = self._key.sign(data)
return b''.join((String(self.algorithm),
String(r.to_bytes(20, 'big') +
s.to_bytes(20, 'big'))))
def verify(self, data, sig):
"""Verify a signature of the specified data using this key"""
try:
packet = SSHPacket(sig)
if packet.get_string() != self.algorithm:
return False
sig = packet.get_string()
packet.check_end()
if len(sig) != 40:
return False
r = int.from_bytes(sig[:20], 'big')
s = int.from_bytes(sig[20:], 'big')
return self._key.verify(data, (r, s))
except PacketDecodeError:
return False
register_public_key_alg(b'ssh-dss', _DSAKey)
register_certificate_alg(b'ssh-dss-cert-v01@openssh.com',
_DSAKey, SSHCertificateV01)
register_certificate_alg(b'ssh-dss-cert-v00@openssh.com',
_DSAKey, SSHCertificateV00)
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