/usr/lib/python3/dist-packages/ecdsa/der.py is in python3-ecdsa 0.11-1.
This file is owned by root:root, with mode 0o644.
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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 | from __future__ import division
import binascii
import base64
from six import int2byte, b, PY3, integer_types, text_type
class UnexpectedDER(Exception):
pass
def encode_constructed(tag, value):
return int2byte(0xa0+tag) + encode_length(len(value)) + value
def encode_integer(r):
assert r >= 0 # can't support negative numbers yet
h = ("%x" % r).encode()
if len(h) % 2:
h = b("0") + h
s = binascii.unhexlify(h)
num = s[0] if isinstance(s[0], integer_types) else ord(s[0])
if num <= 0x7f:
return b("\x02") + int2byte(len(s)) + s
else:
# DER integers are two's complement, so if the first byte is
# 0x80-0xff then we need an extra 0x00 byte to prevent it from
# looking negative.
return b("\x02") + int2byte(len(s)+1) + b("\x00") + s
def encode_bitstring(s):
return b("\x03") + encode_length(len(s)) + s
def encode_octet_string(s):
return b("\x04") + encode_length(len(s)) + s
def encode_oid(first, second, *pieces):
assert first <= 2
assert second <= 39
encoded_pieces = [int2byte(40*first+second)] + [encode_number(p)
for p in pieces]
body = b('').join(encoded_pieces)
return b('\x06') + encode_length(len(body)) + body
def encode_sequence(*encoded_pieces):
total_len = sum([len(p) for p in encoded_pieces])
return b('\x30') + encode_length(total_len) + b('').join(encoded_pieces)
def encode_number(n):
b128_digits = []
while n:
b128_digits.insert(0, (n & 0x7f) | 0x80)
n = n >> 7
if not b128_digits:
b128_digits.append(0)
b128_digits[-1] &= 0x7f
return b('').join([int2byte(d) for d in b128_digits])
def remove_constructed(string):
s0 = string[0] if isinstance(string[0], integer_types) else ord(string[0])
if (s0 & 0xe0) != 0xa0:
raise UnexpectedDER("wanted constructed tag (0xa0-0xbf), got 0x%02x"
% s0)
tag = s0 & 0x1f
length, llen = read_length(string[1:])
body = string[1+llen:1+llen+length]
rest = string[1+llen+length:]
return tag, body, rest
def remove_sequence(string):
if not string.startswith(b("\x30")):
n = string[0] if isinstance(string[0], integer_types) else ord(string[0])
raise UnexpectedDER("wanted sequence (0x30), got 0x%02x" % n)
length, lengthlength = read_length(string[1:])
endseq = 1+lengthlength+length
return string[1+lengthlength:endseq], string[endseq:]
def remove_octet_string(string):
if not string.startswith(b("\x04")):
n = string[0] if isinstance(string[0], integer_types) else ord(string[0])
raise UnexpectedDER("wanted octetstring (0x04), got 0x%02x" % n)
length, llen = read_length(string[1:])
body = string[1+llen:1+llen+length]
rest = string[1+llen+length:]
return body, rest
def remove_object(string):
if not string.startswith(b("\x06")):
n = string[0] if isinstance(string[0], integer_types) else ord(string[0])
raise UnexpectedDER("wanted object (0x06), got 0x%02x" % n)
length, lengthlength = read_length(string[1:])
body = string[1+lengthlength:1+lengthlength+length]
rest = string[1+lengthlength+length:]
numbers = []
while body:
n, ll = read_number(body)
numbers.append(n)
body = body[ll:]
n0 = numbers.pop(0)
first = n0//40
second = n0-(40*first)
numbers.insert(0, first)
numbers.insert(1, second)
return tuple(numbers), rest
def remove_integer(string):
if not string.startswith(b("\x02")):
n = string[0] if isinstance(string[0], integer_types) else ord(string[0])
raise UnexpectedDER("wanted integer (0x02), got 0x%02x" % n)
length, llen = read_length(string[1:])
numberbytes = string[1+llen:1+llen+length]
rest = string[1+llen+length:]
nbytes = numberbytes[0] if isinstance(numberbytes[0], integer_types) else ord(numberbytes[0])
assert nbytes < 0x80 # can't support negative numbers yet
return int(binascii.hexlify(numberbytes), 16), rest
def read_number(string):
number = 0
llen = 0
# base-128 big endian, with b7 set in all but the last byte
while True:
if llen > len(string):
raise UnexpectedDER("ran out of length bytes")
number = number << 7
d = string[llen] if isinstance(string[llen], integer_types) else ord(string[llen])
number += (d & 0x7f)
llen += 1
if not d & 0x80:
break
return number, llen
def encode_length(l):
assert l >= 0
if l < 0x80:
return int2byte(l)
s = ("%x" % l).encode()
if len(s)%2:
s = b("0")+s
s = binascii.unhexlify(s)
llen = len(s)
return int2byte(0x80|llen) + s
def read_length(string):
num = string[0] if isinstance(string[0], integer_types) else ord(string[0])
if not (num & 0x80):
# short form
return (num & 0x7f), 1
# else long-form: b0&0x7f is number of additional base256 length bytes,
# big-endian
llen = num & 0x7f
if llen > len(string)-1:
raise UnexpectedDER("ran out of length bytes")
return int(binascii.hexlify(string[1:1+llen]), 16), 1+llen
def remove_bitstring(string):
num = string[0] if isinstance(string[0], integer_types) else ord(string[0])
if not string.startswith(b("\x03")):
raise UnexpectedDER("wanted bitstring (0x03), got 0x%02x" % num)
length, llen = read_length(string[1:])
body = string[1+llen:1+llen+length]
rest = string[1+llen+length:]
return body, rest
# SEQUENCE([1, STRING(secexp), cont[0], OBJECT(curvename), cont[1], BINTSTRING)
# signatures: (from RFC3279)
# ansi-X9-62 OBJECT IDENTIFIER ::= {
# iso(1) member-body(2) us(840) 10045 }
#
# id-ecSigType OBJECT IDENTIFIER ::= {
# ansi-X9-62 signatures(4) }
# ecdsa-with-SHA1 OBJECT IDENTIFIER ::= {
# id-ecSigType 1 }
## so 1,2,840,10045,4,1
## so 0x42, .. ..
# Ecdsa-Sig-Value ::= SEQUENCE {
# r INTEGER,
# s INTEGER }
# id-public-key-type OBJECT IDENTIFIER ::= { ansi-X9.62 2 }
#
# id-ecPublicKey OBJECT IDENTIFIER ::= { id-publicKeyType 1 }
# I think the secp224r1 identifier is (t=06,l=05,v=2b81040021)
# secp224r1 OBJECT IDENTIFIER ::= {
# iso(1) identified-organization(3) certicom(132) curve(0) 33 }
# and the secp384r1 is (t=06,l=05,v=2b81040022)
# secp384r1 OBJECT IDENTIFIER ::= {
# iso(1) identified-organization(3) certicom(132) curve(0) 34 }
def unpem(pem):
if isinstance(pem, text_type):
pem = pem.encode()
d = b("").join([l.strip() for l in pem.split(b("\n"))
if l and not l.startswith(b("-----"))])
return base64.b64decode(d)
def topem(der, name):
b64 = base64.b64encode(der)
lines = [("-----BEGIN %s-----\n" % name).encode()]
lines.extend([b64[start:start+64]+b("\n")
for start in range(0, len(b64), 64)])
lines.append(("-----END %s-----\n" % name).encode())
return b("").join(lines)
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