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crypto: add chacha20_decrypt; unused for now

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SomberNight
2021-03-10 17:13:42 +01:00
parent 549b9a95df
commit 9740744d70
2 changed files with 38 additions and 5 deletions
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27
electrum/crypto.py
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@@ -338,6 +338,8 @@ def chacha20_poly1305_encrypt(
assert isinstance(nonce, (bytes, bytearray))
assert isinstance(associated_data, (bytes, bytearray, type(None)))
assert isinstance(data, (bytes, bytearray))
assert len(key) == 32, f"unexpected key size: {len(nonce)} (expected: 32)"
assert len(nonce) == 12, f"unexpected nonce size: {len(nonce)} (expected: 12)"
if HAS_CRYPTODOME:
cipher = CD_ChaCha20_Poly1305.new(key=key, nonce=nonce)
if associated_data is not None:
@@ -361,6 +363,8 @@ def chacha20_poly1305_decrypt(
assert isinstance(nonce, (bytes, bytearray))
assert isinstance(associated_data, (bytes, bytearray, type(None)))
assert isinstance(data, (bytes, bytearray))
assert len(key) == 32, f"unexpected key size: {len(nonce)} (expected: 32)"
assert len(nonce) == 12, f"unexpected nonce size: {len(nonce)} (expected: 12)"
if HAS_CRYPTODOME:
cipher = CD_ChaCha20_Poly1305.new(key=key, nonce=nonce)
if associated_data is not None:
@@ -380,14 +384,33 @@ def chacha20_encrypt(*, key: bytes, nonce: bytes, data: bytes) -> bytes:
assert isinstance(key, (bytes, bytearray))
assert isinstance(nonce, (bytes, bytearray))
assert isinstance(data, (bytes, bytearray))
assert len(nonce) == 8, f"unexpected nonce size: {len(nonce)} (expected: 8)"
assert len(key) == 32, f"unexpected key size: {len(nonce)} (expected: 32)"
assert len(nonce) in (8, 12), f"unexpected nonce size: {len(nonce)} (expected: 8 or 12)"
if HAS_CRYPTODOME:
cipher = CD_ChaCha20.new(key=key, nonce=nonce)
return cipher.encrypt(data)
if HAS_CRYPTOGRAPHY:
nonce = bytes(8) + nonce # cryptography wants 16 byte nonces
nonce = bytes(16 - len(nonce)) + nonce # cryptography wants 16 byte nonces
algo = CG_algorithms.ChaCha20(key=key, nonce=nonce)
cipher = CG_Cipher(algo, mode=None, backend=CG_default_backend())
encryptor = cipher.encryptor()
return encryptor.update(data)
raise Exception("no chacha20 backend found")
def chacha20_decrypt(*, key: bytes, nonce: bytes, data: bytes) -> bytes:
assert isinstance(key, (bytes, bytearray))
assert isinstance(nonce, (bytes, bytearray))
assert isinstance(data, (bytes, bytearray))
assert len(key) == 32, f"unexpected key size: {len(nonce)} (expected: 32)"
assert len(nonce) in (8, 12), f"unexpected nonce size: {len(nonce)} (expected: 8 or 12)"
if HAS_CRYPTODOME:
cipher = CD_ChaCha20.new(key=key, nonce=nonce)
return cipher.decrypt(data)
if HAS_CRYPTOGRAPHY:
nonce = bytes(16 - len(nonce)) + nonce # cryptography wants 16 byte nonces
algo = CG_algorithms.ChaCha20(key=key, nonce=nonce)
cipher = CG_Cipher(algo, mode=None, backend=CG_default_backend())
decryptor = cipher.decryptor()
return decryptor.update(data)
raise Exception("no chacha20 backend found")