lwe.h

Go to the documentation of this file.

/*
 * Copyright (c) 2018 XLAB d.o.o.
 *
 * 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.
 */
 
#ifndef CIFER_LWE_H
#define CIFER_LWE_H
 
#include <math.h>
#include <gmp.h>
 
#include "cifer/data/vec.h"
#include "cifer/data/mat.h"
#include "cifer/internal/errors.h"
 
typedef struct cfe_lwe {
    size_t l; // Length of data vectors for inner product
 
    size_t n; // Main security parameters of the scheme
    size_t m; // Number of rows (samples) for the LWE problem
 
    mpz_t bound_x; // Bound for input vector coordinates (for x)
    mpz_t bound_y; // Bound for inner product vector coordinates (for y)
 
    mpz_t p; // Modulus for message space
    mpz_t q; // Modulus for ciphertext and keys
 
    mpf_t sigma_q;
    mpz_t k_sigma_q;
 
    // Matrix A of dimensions m*n is a public parameter
    // of the scheme
    cfe_mat A;
} cfe_lwe;
 
cfe_error cfe_lwe_init(cfe_lwe *s, size_t l, mpz_t bound_x, mpz_t bound_y, size_t n);
 
void cfe_lwe_sec_key_init(cfe_mat *SK, cfe_lwe *s);
 
void cfe_lwe_generate_sec_key(cfe_mat *SK, cfe_lwe *s);
 
void cfe_lwe_pub_key_init(cfe_mat *PK, cfe_lwe *s);
 
cfe_error cfe_lwe_generate_pub_key(cfe_mat *PK, cfe_lwe *s, cfe_mat *SK);
 
void cfe_lwe_fe_key_init(cfe_vec *sk_y, cfe_lwe *s);
 
cfe_error cfe_lwe_derive_fe_key(cfe_vec *sk_y, cfe_lwe *s, cfe_mat *SK, cfe_vec *y);
 
void cfe_lwe_ciphertext_init(cfe_vec *ct, cfe_lwe *s);
 
cfe_error cfe_lwe_encrypt(cfe_vec *ct, cfe_lwe *s, cfe_vec *x, cfe_mat *PK);
 
cfe_error cfe_lwe_decrypt(mpz_t res, cfe_lwe *s, cfe_vec *c, cfe_vec *sk_y, cfe_vec *y);
 
void cfe_lwe_free(cfe_lwe *s);
 
#endif