| // Copyright 2017 Google Inc. |
| // |
| // 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. |
| // |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| syntax = "proto3"; |
| |
| package google.crypto.tink; |
| |
| option java_package = "com.google.crypto.tink.proto"; |
| option java_multiple_files = true; |
| option go_package = "github.com/google/tink/go/proto/aes_gcm_go_proto"; |
| option objc_class_prefix = "TINKPB"; |
| |
| message AesGcmKeyFormat { |
| uint32 key_size = 2; |
| uint32 version = 3; |
| } |
| |
| // key_type: type.googleapis.com/google.crypto.tink.AesGcmKey |
| // |
| // A AesGcmKey is an AEAD key. Mathematically, it represents the functions |
| // Encrypt and Decrypt which we define in the following. |
| // |
| // First, Tink computes a "output prefix" OP by considering the |
| // "OutputPrefixType" message in Keyset.Key and the ID of the key using the |
| // Tink function "AEAD-OutputPrefix": (AesGcmKeys must always be stored in a |
| // keyset). |
| // |
| // AEAD-OutputPrefix(output_prefix_type, id): |
| // if output_prefix_type == RAW: |
| // return ""; |
| // if output_prefix_type == TINK: |
| // return 0x01 + BigEndian(id) |
| // if output_prefix_type == CRUNCHY: |
| // return 0x00 + BigEndian(id) |
| // |
| // Then, the function defined by this is defined as: |
| // [GCM], Section 5.2.1: |
| // * "Encrypt" maps a plaintext P and associated data A to a ciphertext given |
| // by the concatenation OP || IV || C || T. In addition to [GCM], Tink |
| // has the following restriction: IV is a uniformly random initialization |
| // vector of length 12 bytes and T is restricted to 16 bytes. |
| // |
| // * If OP matches the result of AEAD-OutputPrefix, then "Decrypt" maps the |
| // input OP || IV || C || T and A to the the output P in the manner as |
| // described in [GCM], Section 5.2.2. If OP does not match, then "Decrypt" |
| // returns an error. |
| // [GCM]: NIST Special Publication 800-38D: Recommendation for Block Cipher |
| // Modes of Operation: Galois/Counter Mode (GCM) and GMAC. |
| // http://csrc.nist.gov/publications/nistpubs/800-38D/SP-800-38D.pdf. |
| |
| message AesGcmKey { |
| uint32 version = 1; |
| bytes key_value = 3; |
| } |
