You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
94 lines
3.1 KiB
94 lines
3.1 KiB
# MIT License
|
|
#
|
|
# Copyright (c) 2015 Brian Warner and other contributors
|
|
|
|
# Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
# of this software and associated documentation files (the "Software"), to deal
|
|
# in the Software without restriction, including without limitation the rights
|
|
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
# copies of the Software, and to permit persons to whom the Software is
|
|
# furnished to do so, subject to the following conditions:
|
|
#
|
|
# The above copyright notice and this permission notice shall be included in all
|
|
# copies or substantial portions of the Software.
|
|
#
|
|
# 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 RNS.Cryptography.Hashes import sha512
|
|
from .basic import (bytes_to_clamped_scalar,
|
|
bytes_to_scalar, scalar_to_bytes,
|
|
bytes_to_element, Base)
|
|
import hashlib, binascii
|
|
|
|
def H(m):
|
|
return sha512(m)
|
|
|
|
def publickey(seed):
|
|
# turn first half of SHA512(seed) into scalar, then into point
|
|
assert len(seed) == 32
|
|
a = bytes_to_clamped_scalar(H(seed)[:32])
|
|
A = Base.scalarmult(a)
|
|
return A.to_bytes()
|
|
|
|
def Hint(m):
|
|
h = H(m)
|
|
return int(binascii.hexlify(h[::-1]), 16)
|
|
|
|
def signature(m,sk,pk):
|
|
assert len(sk) == 32 # seed
|
|
assert len(pk) == 32
|
|
h = H(sk[:32])
|
|
a_bytes, inter = h[:32], h[32:]
|
|
a = bytes_to_clamped_scalar(a_bytes)
|
|
r = Hint(inter + m)
|
|
R = Base.scalarmult(r)
|
|
R_bytes = R.to_bytes()
|
|
S = r + Hint(R_bytes + pk + m) * a
|
|
return R_bytes + scalar_to_bytes(S)
|
|
|
|
def checkvalid(s, m, pk):
|
|
if len(s) != 64: raise Exception("signature length is wrong")
|
|
if len(pk) != 32: raise Exception("public-key length is wrong")
|
|
R = bytes_to_element(s[:32])
|
|
A = bytes_to_element(pk)
|
|
S = bytes_to_scalar(s[32:])
|
|
h = Hint(s[:32] + pk + m)
|
|
v1 = Base.scalarmult(S)
|
|
v2 = R.add(A.scalarmult(h))
|
|
return v1==v2
|
|
|
|
# wrappers
|
|
|
|
import os
|
|
|
|
def create_signing_key():
|
|
seed = os.urandom(32)
|
|
return seed
|
|
|
|
def create_verifying_key(signing_key):
|
|
return publickey(signing_key)
|
|
|
|
def sign(skbytes, msg):
|
|
"""Return just the signature, given the message and just the secret
|
|
key."""
|
|
if len(skbytes) != 32:
|
|
raise ValueError("Bad signing key length %d" % len(skbytes))
|
|
vkbytes = create_verifying_key(skbytes)
|
|
sig = signature(msg, skbytes, vkbytes)
|
|
return sig
|
|
|
|
def verify(vkbytes, sig, msg):
|
|
if len(vkbytes) != 32:
|
|
raise ValueError("Bad verifying key length %d" % len(vkbytes))
|
|
if len(sig) != 64:
|
|
raise ValueError("Bad signature length %d" % len(sig))
|
|
rc = checkvalid(sig, msg, vkbytes)
|
|
if not rc:
|
|
raise ValueError("rc != 0", rc)
|
|
return True
|
|
|