This is a Python reference implementation of CFRG Internet-Draft "AES-GCM-SIV: Nonce Misuse-Resistant Authenticated Encryption". Draft 9: November 19, 2018. Tested with Python 2 and Python 3.
Do not use.
from reference import AES_GCM_SIV
obj = AES_GCM_SIV(key, nonce)
obj.encrypt(plaintext, aad)
...
obj.decrypt(ciphertext, aad)
This code is placed in the public domain.