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/*-
* Copyright (c) 2017-2022 Ribose Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef RNP_ELG_H_
#define RNP_ELG_H_
#include <stdint.h>
#include "crypto/rng.h"
#include "crypto/mpi.h"
typedef struct pgp_eg_key_t {
pgp_mpi_t p;
pgp_mpi_t g;
pgp_mpi_t y;
/* secret mpi */
pgp_mpi_t x;
} pgp_eg_key_t;
typedef struct pgp_eg_signature_t {
/* This is kept only for packet reading. Implementation MUST
* not create elgamal signatures */
pgp_mpi_t r;
pgp_mpi_t s;
} pgp_eg_signature_t;
typedef struct pgp_eg_encrypted_t {
pgp_mpi_t g;
pgp_mpi_t m;
} pgp_eg_encrypted_t;
bool elgamal_validate_key(const pgp_eg_key_t *key, bool secret);
/*
* Performs ElGamal encryption
* Result of an encryption is composed of two parts - g2k and encm
*
* @param rng initialized rnp::RNG
* @param out encryption result
* @param in plaintext to be encrypted
* @param in_len length of the plaintext
* @param key public key to be used for encryption
*
* @pre out: must be valid pointer to corresponding structure
* @pre in_len: can't be bigger than byte size of `p'
*
* @return RNP_SUCCESS
* RNP_ERROR_OUT_OF_MEMORY allocation failure
* RNP_ERROR_BAD_PARAMETERS wrong input provided
*/
rnp_result_t elgamal_encrypt_pkcs1(rnp::RNG * rng,
pgp_eg_encrypted_t *out,
const uint8_t * in,
size_t in_len,
const pgp_eg_key_t *key);
/*
* Performs ElGamal decryption
*
* @param rng initialized rnp::RNG
* @param out decrypted plaintext. Must be capable of storing at least as much bytes as p size
* @param out_len number of plaintext bytes written will be put here
* @param in encrypted data
* @param key private key
*
* @pre out, in: must be valid pointers
* @pre out: length must be long enough to store decrypted data. Max size of
* decrypted data is equal to bytes size of `p'
*
* @return RNP_SUCCESS
* RNP_ERROR_OUT_OF_MEMORY allocation failure
* RNP_ERROR_BAD_PARAMETERS wrong input provided
*/
rnp_result_t elgamal_decrypt_pkcs1(rnp::RNG * rng,
uint8_t * out,
size_t * out_len,
const pgp_eg_encrypted_t *in,
const pgp_eg_key_t * key);
/*
* Generates ElGamal key
*
* @param rng pointer to PRNG
* @param key generated key
* @param keybits key bitlen
*
* @pre `keybits' > 1024
*
* @returns RNP_ERROR_BAD_PARAMETERS wrong parameters provided
* RNP_ERROR_GENERIC internal error
* RNP_SUCCESS key generated and copied to `seckey'
*/
rnp_result_t elgamal_generate(rnp::RNG *rng, pgp_eg_key_t *key, size_t keybits);
#endif
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