import x25519

basepoint = b'\x09' + b'\x00' * 31

def derive_pubkey(seckey):
	return x25519.x25519(seckey, basepoint)

def ecdh(pubkey, seckey):
	shared_secret = x25519.x25519(seckey, pubkey)
	ored = 0
	for i in shared_secret:
		ored |= i
	if ored == 0:
		raise ValueError
	else:
		return shared_secret

if __name__ == '__main__':
	alice_sk = bytes.fromhex('77076d0a7318a57d3c16c17251b26645df4c2f87ebc0992ab177fba51db92c2a')
	alice_pk = derive_pubkey(alice_sk)
	bob_sk = bytes.fromhex('5dab087e624a8a4b79e17f8b83800ee66f3bb1292618b6fd1c2f8b27ff88e0eb')
	bob_pk = derive_pubkey(bob_sk)

	print(ecdh(alice_pk, bob_sk).hex() == '4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742')
	print(ecdh(bob_pk, alice_sk).hex() == '4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742')