| # Copyright 2021 Google LLC |
| # |
| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS-IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| # [START aead-example] |
| """A command-line utility for encrypting small files with AEAD. |
| |
| It loads cleartext keys from disk - this is not recommended! |
| """ |
| |
| from __future__ import absolute_import |
| from __future__ import division |
| # Placeholder for import for type annotations |
| from __future__ import print_function |
| |
| from absl import app |
| from absl import flags |
| from absl import logging |
| |
| import tink |
| from tink import aead |
| from tink import cleartext_keyset_handle |
| |
| |
| FLAGS = flags.FLAGS |
| |
| flags.DEFINE_enum('mode', None, ['encrypt', 'decrypt'], |
| 'The operation to perform.') |
| flags.DEFINE_string('keyset_path', None, |
| 'Path to the keyset used for encryption.') |
| flags.DEFINE_string('input_path', None, 'Path to the input file.') |
| flags.DEFINE_string('output_path', None, 'Path to the output file.') |
| flags.DEFINE_string('associated_data', None, |
| 'Optional associated data used for the encryption.') |
| |
| |
| def main(argv): |
| del argv # Unused. |
| |
| associated_data = b'' if not FLAGS.associated_data else bytes( |
| FLAGS.associated_data, 'utf-8') |
| |
| # Initialise Tink |
| try: |
| aead.register() |
| except tink.TinkError as e: |
| logging.error('Error initialising Tink: %s', e) |
| return 1 |
| |
| # Read the keyset into a keyset_handle |
| with open(FLAGS.keyset_path, 'rt') as keyset_file: |
| try: |
| text = keyset_file.read() |
| keyset_handle = cleartext_keyset_handle.read(tink.JsonKeysetReader(text)) |
| except tink.TinkError as e: |
| logging.exception('Error reading key: %s', e) |
| return 1 |
| |
| # Get the primitive |
| try: |
| cipher = keyset_handle.primitive(aead.Aead) |
| except tink.TinkError as e: |
| logging.error('Error creating primitive: %s', e) |
| return 1 |
| |
| with open(FLAGS.input_path, 'rb') as input_file: |
| input_data = input_file.read() |
| if FLAGS.mode == 'decrypt': |
| output_data = cipher.decrypt(input_data, associated_data) |
| elif FLAGS.mode == 'encrypt': |
| output_data = cipher.encrypt(input_data, associated_data) |
| else: |
| logging.error( |
| 'Error mode not supported. Please choose "encrypt" or "decrypt".') |
| return 1 |
| |
| with open(FLAGS.output_path, 'wb') as output_file: |
| output_file.write(output_data) |
| |
| |
| if __name__ == '__main__': |
| flags.mark_flags_as_required([ |
| 'mode', 'keyset_path', 'input_path', 'output_path']) |
| app.run(main) |
| # [END aead-example] |