def generateSignature(p, q, g, x, message):
H = int(hexlify(CryptoBox.generateHash(message, 1)), 16)
k = number.getRandomRange(1, q)
r = utils.mod_exp(g, k, p) % q
k_inv = utils.inverse(k, q)
s = (k_inv * (H + x * r)) % q
if (r == 0 or s == 0):
# since it is very unlikely to make a recursive call, function will terminate eventually
return generateSignature(p, q, g, x, message)
return r, s
def verifySignature(p, q, g, y, r, s, message):
if r <= 0 or r >= q or s <= 0 or s >= q:
print "Rejected!"
return
H = int(hexlify(CryptoBox.generateHash(message, 1)), 16)
w = utils.inverse(s, q)
u1 = (H * w) % q
u2 = (r * w) % q
v = ((utils.mod_exp(g, u1, p) * utils.mod_exp(y, u2, p)) % p) % q
return True if v == r else False
def generateSignature(p, q, g, x, message):
H = int(hexlify(CryptoBox.generateHash(message, 1)), 16)
k = number.getRandomRange(1, q)
r = utils.mod_exp(g, k, p) % q
k_inv = utils.inverse(k, q)
s = (k_inv * (H + x * r)) % q
if (r == 0 or s == 0):
# since it is very unlikely to make a recursive call, function will terminate eventually
return generateSignature(p, q, g, x, message)
return r, s
def verifySignature(p, q, g, y, r, s, message):
if r <= 0 or r >= q or s <= 0 or s >= q:
print "Rejected!"
return
H = int(hexlify(CryptoBox.generateHash(message, 1)), 16)
w = utils.inverse(s, q)
u1 = (H * w) % q
u2 = (r * w) % q
v = ((utils.mod_exp(g, u1, p) * utils.mod_exp(y, u2, p)) % p) % q
return True if v == r else False
def MGF(mgfSeed, maskLen):
hLen = len(SHA.new("").digest())
if maskLen > pow(2, 32) * hLen:
print "Mask too long"
return -1
T = ""
for i in range(utils.ceil(maskLen, hLen)):
C = I2OSP(i, 4)
T += CryptoBox.generateHash(mgfSeed + C)
return T[:maskLen]
def MGF(mgfSeed, maskLen):
hLen = len(SHA.new("").digest())
if maskLen > pow(2, 32) * hLen:
print "Mask too long"
return -1
T = ""
for i in range(utils.ceil(maskLen, hLen)):
C = I2OSP(i, 4)
T += CryptoBox.generateHash(mgfSeed + C)
return T[:maskLen]
