def curve25519(self, n, q):
"""
`n` is the private key. It is at least 2**254 and a multiple
of 8. It is the scalar which with we want to multiply.
`q` is the x of point Q. The point Q is the point we want to
multiply. `q` is an element of the field over `p`.
Returns `s`, which is the x of `n` * `Q`
"""
assert len(n) == 32
assert len(q) == 32
n = little_endian().from_string(n)
assert n >= pow(2, 254)
assert n % 8 == 0
q = little_endian().from_string(q)
curve25519 = curve(486662, pow(2, 255) - 19)
(Q0, Q1) = curve25519.points(q)
nQ = curve25519.multiply(Q0, n)
assert nQ[0] == curve25519.multiply(Q1, n)[0]
s = nQ[0]
return little_endian().to_string(s)
def create_secret_key_str(self):
return little_endian().to_string(self.create_secret_key_num())
