def client_handshake_begin(ecdsa_priv, ecdh_priv, server_pub, curve=identity.DEFAULT_KEYTYPE, kdf=DEFAULT_KDF):
"""
Start the handshake
:param ecdsa_priv: long term signing privkey
:param ecdh_priv: temporary session ecc privkey
:param server_pub: server long term pub key
:param curve: EC Curve name
:param kdf: Key derivation mechanism
:return: secret aes key, handshake message to send
"""
session_pub_str = ecdh_priv.get_verifying_key().to_pem()
# sign our session key
signature = identity.sign_string(ecdsa_priv, session_pub_str + kdf + curve.openssl_name)
message = {
"pub": ecdsa_priv.get_verifying_key().to_pem(),
"session": session_pub_str,
"signature": signature,
"keytype": curve.openssl_name,
"kdf": kdf,
}
shared = identity.ecdh(ecdh_priv, server_pub)
secret = derive_key(kdf, shared)
return secret, message
def client_handshake_finish(client_priv, secret, challenge):
"""
Sign the challenge from the server's handshake response
:param client_priv:
:param secret:
:param challenge:
:return:
"""
pubkeyhash = identity.pubkeyhash(client_priv.get_verifying_key())
plaintext = aes_decrypt_str(secret, challenge["iv"], challenge["challenge"])
signature = identity.sign_string(client_priv, plaintext)
return {"signature": signature,
"fingerprint": pubkeyhash
}
def test_generate_sign(tmpdir):
"""
Test key generation
:param tmpdir:
:return:
"""
datafolder = tmpdir.strpath
identity.first_run(datafolder)
keyfile = identity.get_priv_keyfilename(datafolder)
assert os.path.isfile(keyfile)
key = identity.load(keyfile)
signature = identity.sign_string(key, "hello")
pub = identity.loadpub(identity.get_pub_keyfilename(datafolder))
assert identity.verify_string(pub, signature, "hello")
def send_data(signer, sessionkey, data):
"""
Encrypt some data and sign it
:param signer: signing key
:param sessionkey: encryption key
:param data: message (expected string)
:return: dict containing fingerprint, signature, iv and ciphertext
"""
ctext, iv = aes_encrypt_str(sessionkey, str(data))
signature = identity.sign_string(signer, ctext)
pubkeyhash = hashlib.sha512(signer.get_verifying_key().to_der()).hexdigest()
return {
"fingerprint": pubkeyhash,
"signature": signature,
"iv": iv,
"ciphertext": ctext
}
