Method decrypt

src/borg/crypto/key.py:878–888

(self, id, data)

        return self.cipher.encrypt(data, header=header, iv=iv, aad=id)

    def decrypt(self, id, data):
        # to decrypt existing data, we need to get a cipher configured for the sessionid and iv from header
        self.assert_type(data[0], id)
        iv_48bit = data[2:8]
        sessionid = bytes(data[8:32])
        iv = int.from_bytes(iv_48bit, "big")
        cipher = self._get_cipher(sessionid, iv)
        try:
            return cipher.decrypt(data, aad=id)
        except IntegrityError as e:
            raise IntegrityError(f"Chunk {bin_to_hex(id)}: Could not decrypt [{str(e)}]")

    def init_from_given_data(self, *, crypt_key, id_key, chunk_seed):
        assert len(crypt_key) in (32 + 32, 32 + 128)