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"""Tests for AES-256-GCM webcrypto variant."""
import os
import blake3
import pytest
from meshbay_common.crypto import generate_gek
from meshbay_common.webcrypto import chunk_key_aes, decrypt_chunk_aes, encrypt_chunk_aes
def test_aes_roundtrip():
gek = generate_gek()
data = os.urandom(1024 * 1024) # 1 MB
fh = blake3.blake3(data).digest()
key = chunk_key_aes(gek, fh, 0)
nonce, ct = encrypt_chunk_aes(key, data)
assert decrypt_chunk_aes(key, nonce, ct) == data
def test_aes_key_distinct_from_chacha_key():
"""AES and ChaCha20 keys for the same chunk must differ."""
from meshbay_common.crypto import chunk_key as chacha_key
gek = generate_gek()
data = os.urandom(100)
fh = blake3.blake3(data).digest()
aes_k = chunk_key_aes(gek, fh, 0)
chacha_k = chacha_key(gek, fh, 0)
assert aes_k != chacha_k
def test_aes_wrong_key_rejected():
gek = generate_gek()
data = b"private content"
fh = blake3.blake3(data).digest()
key = chunk_key_aes(gek, fh, 0)
nonce, ct = encrypt_chunk_aes(key, data)
wrong_key = chunk_key_aes(generate_gek(), fh, 0)
with pytest.raises(Exception):
decrypt_chunk_aes(wrong_key, nonce, ct)
def test_aes_chunk_keys_unique_per_chunk():
gek = generate_gek()
data = os.urandom(32)
fh = blake3.blake3(data).digest()
keys = {chunk_key_aes(gek, fh, i) for i in range(5)}
assert len(keys) == 5 # all distinct
def test_aes_gek_wrap_unwrap_roundtrip():
from cryptography.hazmat.primitives.asymmetric.x25519 import X25519PrivateKey
from meshbay_common.crypto import (
pk_to_raw,
sk_to_raw,
unwrap_gek_aes,
wrap_gek_aes,
)
gek = generate_gek()
sk = X25519PrivateKey.generate()
pk_raw = pk_to_raw(sk.public_key())
sk_raw = sk_to_raw(sk)
bundle = wrap_gek_aes(gek, pk_raw)
recovered = unwrap_gek_aes(bundle, sk_raw, pk_raw)
assert recovered == gek
def test_aes_gek_wrap_wrong_key_rejected():
from cryptography.hazmat.primitives.asymmetric.x25519 import X25519PrivateKey
from meshbay_common.crypto import pk_to_raw, sk_to_raw, unwrap_gek_aes, wrap_gek_aes
gek = generate_gek()
sk_a = X25519PrivateKey.generate()
sk_b = X25519PrivateKey.generate()
bundle = wrap_gek_aes(gek, pk_to_raw(sk_a.public_key()))
with pytest.raises(Exception):
unwrap_gek_aes(bundle, sk_to_raw(sk_b), pk_to_raw(sk_b.public_key()))
def test_aes_gek_wrap_differs_from_chacha_wrap():
from cryptography.hazmat.primitives.asymmetric.x25519 import X25519PrivateKey
from meshbay_common.crypto import (
pk_to_raw,
wrap_gek,
wrap_gek_aes,
)
gek = generate_gek()
sk = X25519PrivateKey.generate()
pk_raw = pk_to_raw(sk.public_key())
bundle_aes = wrap_gek_aes(gek, pk_raw)
bundle_chacha = wrap_gek(gek, pk_raw)
assert bundle_aes["wrapped_b64"] != bundle_chacha["wrapped_b64"]
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