def check_signature(public_key, z, signature, curve: Curve=curve_P256):
u1 = (inverse_of(signature[1], curve.n) * z) % curve.n
u2 = (inverse_of(signature[1], curve.n) * signature[0]) % curve.n
u1G = multiply(curve.g, u1)
u2Q = multiply(public_key, u2)
P = points_sum(u1G, u2Q)
_r = P.x % curve.n
if signature[0] == _r:
return 1
else:
return 0
def decrypt(private_key, s, T: Point, c_text, curve: Curve =curve_P256):
l = 128
U = multiply(T, private_key)
bytes_u_x_ = bytes(str(U.x)[:8], 'utf-8')
kdf_T_U = int.from_bytes(PBKDF2(str(T.x), bytes_u_x_).read(int(l / 8)), 'big')
r = s ^ kdf_T_U
keylen = 256
_t_len = keylen + 128
len_ = (keylen + _t_len) / 8
pre_key = PBKDF2(str(r), 'salt').read(int(len_))
t_ = int.from_bytes(pre_key, 'big') >> keylen
K = int(bin(int.from_bytes(pre_key, 'big') << _t_len)[2:keylen + 2], 2)
t = t_ % curve.n
T_ = multiply(curve.g, t, curve.a)
if T_.x == T.x and T_.y == T.y:
obj = AES.new(str(K)[:32], AES.MODE_CBC, "ABCDEFGHABCDEFGH")
return obj.decrypt(c_text)
else:
return 'incorrect'
def encrypt(public_key: Point, msg, curve: Curve =curve_P256):
l = 128
r = int(bin(get_random_k())[2:l+2], 2)
keylen = 256
_t_len = keylen + l
len_ = (keylen + _t_len) / 8
pre_key = PBKDF2(str(r), 'salt').read(int(len_))
t_ = int.from_bytes(pre_key, 'big') >> keylen
K = int(bin(int.from_bytes(pre_key, 'big') << _t_len)[2:keylen + 2], 2)
t = t_ % curve.n
T = multiply(curve.g, t, curve.a)
U = multiply(public_key, t, curve.a)
bytes_u_x_ = bytes(str(U.x)[:8], 'utf-8')
kdf_T_U = int.from_bytes(PBKDF2(str(T.x), bytes_u_x_).read(int(l / 8)), 'big')
s = r ^ kdf_T_U
obj = AES.new(str(K)[:32], AES.MODE_CBC, "ABCDEFGHABCDEFGH")
_n = 16 - msg.__len__() % 16
rand_str = ''.join(' ' for i in range(_n))
c_text = obj.encrypt(msg+rand_str)
return s, T, c_text
def get_signature(z, private_key, curve: Curve=curve_P256):
s = r = k = 0
_r = lambda __k: multiply(curve.g, k).x % curve.n
while s == 0:
k = get_random_k()
while r == 0:
r = _r(k)
_k_ = inverse_of(k, curve.n)
what = (z + r * private_key)
s = (_k_ * what) % curve.n
return r, s
def get_public_key(private_key, curve: Curve=curve_P256):
return multiply(curve.g, private_key, curve.a)
def get_secret(private_key, public_key: Point, curve: Curve=curve_P256):
return multiply(public_key, private_key, curve.a)