def verifySignature(pub, message, signature):
block = b'\x00' + challenge39.encryptbytes(pub, signature)
r = re.compile(b'\x00\x01\xff+?\x00(.{20})', re.DOTALL)
m = r.match(block)
if not m:
return False
digest = m.group(1)
sha1 = hashlib.sha1()
sha1.update(message)
return digest == sha1.digest()
def verifySignature(pub, message, signature):
block = b'\x00' + challenge39.encryptbytes(pub, signature)
r = re.compile(b'\x00\x01\xff+?\x00(.{20})', re.DOTALL)
m = r.match(block)
if not m:
return False
digest = m.group(1)
sha1 = hashlib.sha1()
sha1.update(message)
return digest == sha1.digest()
def encrypt(plaintext):
return challenge39.encryptbytes(pub, plaintext)
raise Exception('unexpected')
r = minR
ai = max(a, (2*B + r*n + s - 1) // s)
bi = min(b, (3*B - 1 + r*n) // s)
if ai > bi:
raise Exception('unexpected')
return [(ai, bi)]
def deducePlaintext(ciphertext, pub, parityOracle):
e, n = pub
k = (n.bit_length() + 7) // 8
B = 2**(8*(k-2))
c0 = challenge39.bytestonum(ciphertext)
M = [(2*B, 3*B - 1)]
(s, c) = computeFirstS(e, n, B, c0, parityOracle)
M = getNextInterval(n, M, s, B)
while True:
if len(M) == 1 and M[0][0] == M[0][1]:
m = M[0][0]
return b'\x00' + challenge39.numtobytes(m)
(s, c) = computeNextS(e, n, M, s, B, c0)
M = getNextInterval(n, M, s, B)
if __name__ == '__main__':
_, n = pub
plaintext = padPKCS15(b'kick it, CC', n)
ciphertext = challenge39.encryptbytes(pub, plaintext)
plaintext2 = deducePlaintext(ciphertext, pub, parityOracle)
if plaintext2 != plaintext:
raise Exception(plaintext2 + b' != ' + plaintext)
def encrypt(plaintext):
return challenge39.encryptbytes(pub, plaintext)
