def make_fernet(key: bytes) -> Fernet:
"""Makes a Fernet encrypter/decrypter from the derived key.
Args:
key (bytes): The derived key, in bytes.
Returns:
A Fernet instance, which can be used to either encrypt or decrypt data.
"""
TypeCheck.ensure_bytes(key, "key")
return Fernet(base64.urlsafe_b64encode(key))
def encode_salt(salt: bytes) -> str:
"""Encodes the raw salt as string.
Args:
salt (bytes): The raw salt, in bytes.
Returns:
The Base64-encoded string of the raw salt
"""
TypeCheck.ensure_bytes(salt, "salt")
return str(base64.b64encode(salt), "utf-8")
def decrypt(self, encrypted_data: bytes) -> bytes:
"""Decrypts the encrypted data.
Args:
encrypted_data (bytes): The encrypted data to be decrypted.
Returns:
The decrypted data, in bytes, which is decrypted using the `Fernet` (created by `Cryptography.make_fernet`)
"""
TypeCheck.ensure_bytes(encrypted_data, "encrypted_data")
if self.is_encrypt:
raise ValueError("Not a decrypter!")
fernet = Cryptographer.make_fernet(self.key)
try:
return fernet.decrypt(encrypted_data)
except InvalidToken:
raise
def encrypt(self, raw_data: bytes) -> bytes:
"""Encrypts raw data.
Args:
raw_data (bytes): The raw data to be encrypted.
Returns:
The encrypted data, in bytes, which is encrypted using the `Fernet` (created by `Cryptography.make_fernet`)
Raises:
ValueError: A decrypter is used to encrypt.
"""
TypeCheck.ensure_bytes(raw_data, "raw_data")
if not self.is_encrypt:
raise ValueError("Not an encrypter!")
fernet = Cryptographer.make_fernet(self.key)
return fernet.encrypt(raw_data)
def make_kdf(salt: bytes) -> PBKDF2HMAC:
"""Makes a key derivation function from raw salt.
Args:
salt (bytes): The raw salt, in bytes.
Returns:
A PBKDF2HMAC instance, which can be used to derive key from the authentication key.
"""
TypeCheck.ensure_bytes(salt, "salt")
return PBKDF2HMAC(
algorithm=hashes.SHA512(),
length=32,
salt=salt,
iterations=10000,
backend=default_backend(),
)
def test_ensure_bytes():
assert TypeCheck.ensure_bytes(b"3123") is None
assert TypeCheck.ensure_bytes(bytes(132423)) is None
assert TypeCheck.ensure_bytes("n".encode()) is None
with pytest.raises(TypeError):
TypeCheck.ensure_bytes(8)
with pytest.raises(TypeError):
TypeCheck.ensure_bytes(["string"])
