Basic example of pyUmbral

umbral-simple-api.py

from umbral import umbral, keys

# Generate umbral keys for Alice.
alices_private_key = keys.UmbralPrivateKey.gen_key()
alices_public_key = private_key.get_pubkey()

# Generate umbral keys for Bob.
bobs_private_key = keys.UmbralPrivateKey.gen_key()
bobs_public_key = private_key.get_pubkey()

# Encrypt data with Alice’s public key.
plaintext = b'Proxy Re-encryption is cool!'
ciphertext, capsule = umbral.encrypt(alices_public_key, plaintext)

# Decrypt data with Alice’s private key.
cleartext = umbral.decrypt(capsule, alices_private_key, ciphertext, alices_public_key)
 
 # Alice generates split re-encryption keys for Bob with “M of N”.
kfrags = umbral.split_rekey(alices_private_key, bobs_public_key, 10, 20)

# Ursula re-encrypts the capsule to obtain a cfrag.
# Bob attaches the cfrags to the capsule.
for kfrag in kfrags:
    cfrag = umbral.reencrypt(kfrag, capsule)
    capsule.attach_cfrag(cfrag)

# Bob opens the capsule.
cleartext = umbral.decrypt(ciphertext, capsule, bobs_private_key, alices_public_key)