/*
 * 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
 *
 *     https://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 = "proto2";

 option optimize_for = LITE_RUNTIME;
 
 package rlwe;
 
 option go_package = "github.com/google/shell-encryption";
 
 // NTT Polynomial
 message SerializedNttPolynomial {
   // Coefficients of the polynomial
   optional bytes coeffs = 1;
 
   // Number of coefficients of the polynomial.
   optional int32 num_coeffs = 2;
 }
 
 // RLWE Ciphertext
 message SerializedSymmetricRlweCiphertext {
   // Polynomials composing the ciphertext
   repeated SerializedNttPolynomial c = 1;
 
   // The power of the secret key that the ciphertext is encrypted with.
   optional int32 power_of_s = 2;
 
   // A heuristic on the amount of error in the ciphertext.
   optional double error = 3;
 }
 
 // RLWE RelinearizationKey
 message SerializedRelinearizationKey {
   // Polynomial composing the matrix
   repeated SerializedNttPolynomial c = 1;
 
   // The modulus used to decompose the coefficients of the polynomials. Ranges
   // from 1 to the number of bits of the modulus.
   optional int32 log_decomposition_modulus = 2;
 
   // For n parts, the key can relinearize an n-component ciphertext to a
   // 2-component ciphertext.
   optional int32 num_parts = 3;
 
   // Seed used to compress this key.
   optional bytes prng_seed = 4;  // Required
 
   // The power of s that corresponds to the key. The field is 1 if the key is
   // RelinearizationKey.
   optional int32 power_of_s = 5;
 }
 
 // RLWE GaloisKeys.
 message SerializedGaloisKey {
   // The key-switching matrix
   optional SerializedRelinearizationKey key = 1;
 }