def encrypt(self, passphrases_and_keys, symmetric_algorithm=9):
cipher, key_bytes, key_block_bytes = self.get_cipher(
symmetric_algorithm)
if not cipher:
raise Exception("Unsupported cipher")
prefix = Crypto.Random.new().read(key_block_bytes)
prefix += prefix[-2:]
key = Crypto.Random.new().read(key_bytes)
session_cipher = cipher(key)(None)
to_encrypt = prefix + self._message.to_bytes()
mdc = OpenPGP.ModificationDetectionCodePacket(
Crypto.Hash.SHA.new(to_encrypt + b'\xD3\x14').digest())
to_encrypt += mdc.to_bytes()
def doEncrypt(cipher):
ctx = cipher.encryptor()
return lambda x: ctx.update(x) + ctx.finalize()
encrypted = [
OpenPGP.IntegrityProtectedDataPacket(
self._block_pad_unpad(key_block_bytes, to_encrypt,
doEncrypt(session_cipher)))
]
if not isinstance(passphrases_and_keys,
collections.Iterable) or hasattr(
passphrases_and_keys, 'encode'):
passphrases_and_keys = [passphrases_and_keys]
for psswd in passphrases_and_keys:
if isinstance(psswd, OpenPGP.PublicKeyPacket):
if not psswd.key_algorithm in [1, 2, 3]:
raise Exception("Only RSA keys are supported.")
rsa = self.__class__(psswd).public_key()
pkcs1 = Crypto.Cipher.PKCS1_v1_5.new(rsa)
esk = pkcs1.encrypt(
pack('!B', symmetric_algorithm) + key +
pack('!H', OpenPGP.checksum(key)))
esk = pack('!H', OpenPGP.bitlength(esk)) + esk
encrypted = [
OpenPGP.AsymmetricSessionKeyPacket(
psswd.key_algorithm, psswd.fingerprint(), esk)
] + encrypted
elif hasattr(psswd, 'encode'):
psswd = psswd.encode('utf-8')
s2k = OpenPGP.S2K(Crypto.Random.new().read(10))
packet_cipher = cipher(s2k.make_key(psswd, key_bytes))(None)
esk = self._block_pad_unpad(
key_block_bytes,
pack('!B', symmetric_algorithm) + key,
doEncrypt(packet_cipher))
encrypted = [
OpenPGP.SymmetricSessionKeyPacket(s2k, esk,
symmetric_algorithm)
] + encrypted
return OpenPGP.Message(encrypted)