def sigdecode_der(sig_der, order):
# return der.encode_sequence(der.encode_integer(r), der.encode_integer(s))
rs_strings, empty = der.remove_sequence(sig_der)
if empty != b(""):
raise der.UnexpectedDER("trailing junk after DER sig: %s" %
binascii.hexlify(empty))
r, rest = der.remove_integer(rs_strings)
s, empty = der.remove_integer(rest)
if empty != b(""):
raise der.UnexpectedDER("trailing junk after DER numbers: %s" %
binascii.hexlify(empty))
return r, s
def from_der(klass, string):
# [[oid_ecPublicKey,oid_curve], point_str_bitstring]
s1,empty = der.remove_sequence(string)
if empty != "":
raise der.UnexpectedDER("trailing junk after DER pubkey: %s" %
binascii.hexlify(empty))
s2,point_str_bitstring = der.remove_sequence(s1)
# s2 = oid_ecPublicKey,oid_curve
oid_pk, rest = der.remove_object(s2)
oid_curve, empty = der.remove_object(rest)
if empty != "":
raise der.UnexpectedDER("trailing junk after DER pubkey objects: %s" %
binascii.hexlify(empty))
assert oid_pk == oid_ecPublicKey, (oid_pk, oid_ecPublicKey)
curve = find_curve(oid_curve)
point_str, empty = der.remove_bitstring(point_str_bitstring)
if empty != "":
raise der.UnexpectedDER("trailing junk after pubkey pointstring: %s" %
binascii.hexlify(empty))
assert point_str.startswith("\x00\x04")
return klass.from_string(point_str[2:], curve)
def from_der(klass, string, hashfunc=sha1):
# SEQ([int(1), octetstring(privkey),cont[0], oid(secp224r1),
# cont[1],bitstring])
s, empty = der.remove_sequence(string)
if empty != b(""):
raise der.UnexpectedDER("trailing junk after DER privkey: %s" %
binascii.hexlify(empty))
one, s = der.remove_integer(s)
if one != 1:
raise der.UnexpectedDER("expected '1' at start of DER privkey,"
" got %d" % one)
privkey_str, s = der.remove_octet_string(s)
tag, curve_oid_str, s = der.remove_constructed(s)
if tag != 0:
raise der.UnexpectedDER("expected tag 0 in DER privkey,"
" got %d" % tag)
curve_oid, empty = der.remove_object(curve_oid_str)
if empty != b(""):
raise der.UnexpectedDER("trailing junk after DER privkey "
"curve_oid: %s" % binascii.hexlify(empty))
curve = find_curve(curve_oid)
# we don't actually care about the following fields
#
# tag, pubkey_bitstring, s = der.remove_constructed(s)
# if tag != 1:
# raise der.UnexpectedDER("expected tag 1 in DER privkey, got %d"
# % tag)
# pubkey_str = der.remove_bitstring(pubkey_bitstring)
# if empty != "":
# raise der.UnexpectedDER("trailing junk after DER privkey "
# "pubkeystr: %s" % binascii.hexlify(empty))
# our from_string method likes fixed-length privkey strings
if len(privkey_str) < curve.baselen:
privkey_str = b("\x00") * (curve.baselen -
len(privkey_str)) + privkey_str
return klass.from_string(privkey_str, curve, hashfunc)