package/python-spake2: new package

SPAKE2 password-authenticated key exchange (in pure python).

This library implements the SPAKE2 password-authenticated key
exchange ("PAKE") algorithm. This allows two parties, who share a
weak password, to safely derive a strong shared secret (and
therefore build an encrypted+authenticated channel).

https://github.com/warner/python-spake2

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

support/testing/tests/package/sample_python_spake2.py

@@ -0,0 +1,22 @@
+from binascii import hexlify
+
+from spake2 import SPAKE2_A, SPAKE2_B
+
+
+shared_password = b"This Is The Password!"
+
+alice = SPAKE2_A(shared_password)
+alice_msg = alice.start()
+
+bob = SPAKE2_B(shared_password)
+bob_msg = bob.start()
+
+# Alice and Bob exchange their messages...
+
+alice_key = alice.finish(bob_msg)
+bob_key = bob.finish(alice_msg)
+
+print("alice_key:", hexlify(alice_key))
+print("  bob_key:", hexlify(bob_key))
+
+assert alice_key == bob_key