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tools: simplify ed25519cosi

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pull/25/head
Pavol Rusnak 7 years ago
parent 63737f59b0
commit 98bdd99b97
No known key found for this signature in database
GPG Key ID: 91F3B339B9A02A3D
1 changed files with 21 additions and 192 deletions
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213
tools/ed25519cosi.py
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@ -1,211 +1,39 @@
import sys
from functools import reduce
import binascii
import ed25519raw
import pyblake2
def hex(by):
return binascii.hexlify(by).decode()
def combine_keys(pks):
combine = None
for pk in pks:
P = ed25519raw.decodepoint(pk)
if not combine:
combine = P
else:
combine = ed25519raw.edwards(combine, P)
P = [ed25519raw.decodepoint(pk) for pk in pks]
combine = reduce(ed25519raw.edwards, P)
return ed25519raw.encodepoint(combine)
def combine_sig(R, sigs):
s = 0
for si in sigs:
s += ed25519raw.decodeint(si)
s = s % ed25519raw.l
S = [ed25519raw.decodeint(si) for si in sigs]
s = sum(S) % ed25519raw.l
sig = R + ed25519raw.encodeint(s)
return sig
def binom(n, k):
b = 1
for i in range(1, k + 1):
b = b * (n - k + i) // i
return b
def compute_mask(combination, m, n):
result = 0
signer = 0
while m > 0:
m = m - 1
n = n - 1
numst = binom(n, m)
while combination >= numst:
combination -= numst
signer = signer + 1
n = n - 1
numst = binom(n, m)
result |= 1 << signer
signer = signer + 1
return result
def createPubkey():
print('Enter randomness: ', end='')
seckey = ed25519raw.H(input().encode())[0:32]
pubkey = ed25519raw.publickey(seckey)
print('Secret Key: %s' % hex(seckey))
print('Public Key: %s' % hex(pubkey))
def combinePubkeys(m, n):
if binom(n, m) > 100:
raise Exception('Too many keys')
pks = []
for i in range(0, n):
print('Enter pubkey %d: ' % i, end='')
pk = binascii.unhexlify(input())
# remove 00 prefix if present
if len(pk) == 33:
pk = pk[1:]
pks.append(ed25519raw.decodepoint(pk))
for i in range(0, binom(n, m)):
mask = compute_mask(i, m, n)
sum = None
for j in range(0, n):
if mask & (1 << j) != 0:
if sum is None:
sum = pks[j]
else:
sum = ed25519raw.edwards(sum, pks[j])
pk = ed25519raw.encodepoint(sum)
print('Key %02x: %s' % (mask, hex(pk)))
def get_nonce(sk, data, ctr):
h = ed25519raw.H(sk)
b = ed25519raw.b
a = 2 ** (b - 2) + sum(2 ** i * ed25519raw.bit(h, i) for i in range(3, b - 2))
r = ed25519raw.Hint(bytes([h[i] for i in range(b >> 3, b >> 2)]) + data + binascii.unhexlify('%08x' % ctr))
R = ed25519raw.scalarmult(ed25519raw.B, r)
return r, ed25519raw.encodepoint(R)
def phase1(data):
digest = pyblake2.blake2s(data).digest()
print('Digest: %s' % hex(digest))
print('Enter counter (small integer): ', end='')
ctr = int(input())
print('Enter privkey: ', end='')
seckey = binascii.unhexlify(input())
_, R = get_nonce(seckey, digest, ctr)
print('Local commit: %s' % hex(R))
def combinePhase1(m):
commits = []
for i in range(0, m):
print('Enter commit %d: ' % i, end='')
commits.append(binascii.unhexlify(input()))
print('Global commit: %s' % hex(combine_keys(commits)))
def phase2(data):
digest = pyblake2.blake2s(data).digest()
print('Digest: %s' % hex(digest))
print('Enter combined commitment: ', end='')
R = binascii.unhexlify(input())
print('Enter combined public key: ', end='')
pk = binascii.unhexlify(input())
print('Enter counter: ', end='')
ctr = int(input())
print('Enter privkey: ', end='')
seckey = binascii.unhexlify(input())
(r, Ri) = get_nonce(seckey, digest, ctr)
h = ed25519raw.H(seckey)
b = ed25519raw.b
a = 2**(b - 2) + sum(2**i * ed25519raw.bit(h, i) for i in range(3, b - 2))
S = (r + ed25519raw.Hint(R + pk + digest) * a) % ed25519raw.l
print('Local commit: %s' % hex(Ri))
print('Local sig: %s' % hex(ed25519raw.encodeint(S)))
def combinePhase2(m):
sigs = []
print('Enter global commit: ', end='')
R = binascii.unhexlify(input())
for i in range(0, m):
print('Enter sig %d: ' % i, end='')
sigs.append(binascii.unhexlify(input()))
sig = combine_sig(R, sigs)
print('Combined sig: %s' % hex(sig))
def checkSignature(data):
digest = pyblake2.blake2s(data).digest()
print('Digest: %s' % hex(digest))
print('Enter Public Key: ', end='')
pubkey = binascii.unhexlify(input())
print('Enter Sig: ', end='')
sig = binascii.unhexlify(input())
ed25519raw.checkvalid(sig, digest, pubkey)
print('Valid Signature!')
def usage():
print('Usage: keyctl phase options')
print('Phases:')
print(' keyctl create_pub: create single public keys')
print(' keyctl combine_pub m n: create combined public keys')
print(' keyctl ph1 file.bin: compute partial commitment')
print(' keyctl combine_ph1 m: combine commitments')
print(' keyctl ph2 file.bin: compute partial signature')
print(' keyctl combine_ph2 m: combine signatures')
print(' keyctl check_sig file.bin: check signature')
def main():
if len(sys.argv) < 2:
usage()
return 1
func = sys.argv[1]
if func == 'create_pub':
createPubkey()
elif func == 'combine_pub':
m = int(sys.argv[2])
n = int(sys.argv[3])
combinePubkeys(m, n)
elif func == 'ph1':
filename = sys.argv[2]
data = open(filename, 'rb').read()
phase1(data)
elif func == 'combine_ph1':
m = int(sys.argv[2])
combinePhase1(m)
elif func == 'ph2':
filename = sys.argv[2]
data = open(filename, 'rb').read()
phase2(data)
elif func == 'combine_ph2':
m = int(sys.argv[2])
combinePhase2(m)
elif func == 'check_sig':
filename = sys.argv[2]
data = open(filename, 'rb').read()
checkSignature(data)
else:
usage()
def self_test(digest):
def to_hex(by):
return binascii.hexlify(by).decode()
def test(data):
N = 3
keyset = [0, 2]
digest = pyblake2.blake2s(data).digest()
print('Digest: %s' % hex(digest))
digest = binascii.unhexlify(digest)
print('Digest: %s' % to_hex(digest))
sks = []
pks = []
nonces = []
@ -215,22 +43,22 @@ def test(data):
print('----- Key %d ------' % (i + 1))
seckey = bytes([0x41 + i]) * 32
pubkey = ed25519raw.publickey(seckey)
print('Secret Key: %s' % hex(seckey))
print('Public Key: %s' % hex(pubkey))
print('Secret Key: %s' % to_hex(seckey))
print('Public Key: %s' % to_hex(pubkey))
sks.append(seckey)
pks.append(pubkey)
ctr = 0
r, R = get_nonce(seckey, digest, ctr)
print('Local nonce: %s' % hex(ed25519raw.encodeint(r)))
print('Local commit: %s' % hex(R))
print('Local nonce: %s' % to_hex(ed25519raw.encodeint(r)))
print('Local commit: %s' % to_hex(R))
nonces.append(r)
commits.append(R)
global_pk = combine_keys([pks[i] for i in keyset])
global_R = combine_keys([commits[i] for i in keyset])
print('-----------------')
print('Global pubkey: %s' % hex(global_pk))
print('Global commit: %s' % hex(global_R))
print('Global pubkey: %s' % to_hex(global_pk))
print('Global commit: %s' % to_hex(global_R))
print('-----------------')
for i in range(0, N):
@ -242,18 +70,19 @@ def test(data):
b = ed25519raw.b
a = 2**(b - 2) + sum(2**i * ed25519raw.bit(h, i) for i in range(3, b - 2))
S = (r + ed25519raw.Hint(global_R + global_pk + digest) * a) % ed25519raw.l
print('Local sig %d: %s' % (i + 1, hex(ed25519raw.encodeint(S))))
print('Local sig %d: %s' % (i + 1, to_hex(ed25519raw.encodeint(S))))
sigs.append(ed25519raw.encodeint(S))
print('-----------------')
sig = combine_sig(global_R, [sigs[i] for i in keyset])
print('Global sig: %s' % hex(sig))
print('Global sig: %s' % to_hex(sig))
ed25519raw.checkvalid(sig, digest, global_pk)
print('Valid Signature!')
if __name__ == '__main__':
import sys
if len(sys.argv) > 1:
test(data=sys.argv[1].encode())
self_test(digest=sys.argv[1])
else:
test(data=b'test')
self_test(digest='4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b')

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