ctr.h
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/*
* Copyright (C) 2015 Freie Universität Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup sys_crypto
* @{
*
* @file ctr.h
* @brief Counter mode of operation for block ciphers
*
* @author Freie Universitaet Berlin, Computer Systems & Telematics
* @author Nico von Geyso <nico.geyso@fu-berlin.de>
*/
#ifndef CRYPTO_MODES_CTR_H
#define CRYPTO_MODES_CTR_H
#include "crypto/ciphers.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Encrypt data of arbitrary length in counter mode.
*
* @param cipher Already initialized cipher struct
* @param nonce_counter A nounce and a counter encoded in 16 octets. The counter
* will be modified in each block encryption.
* @param nonce_len Length of the nonce in octets. As nounce and counter
* have to fit in one aligned 16 octet block, maximum
* length of nonce is limited by input_len:
* 16 - log_2(input_len)
* @param input pointer to input data to encrypt
* @param length length of the input data
* @param output pointer to allocated memory for encrypted data. It has
* to be of size data_len.
*/
int cipher_encrypt_ctr(cipher_t* cipher, uint8_t nonce_counter[16],
uint8_t nonce_len, uint8_t* input, size_t length,
uint8_t* output);
/**
* @brief Decrypt data of arbitrary length in counter mode. Encryption and
* decryption in ctr mode are basically the same.
*
* @param cipher Already initialized cipher struct
* @param nonce_counter A nounce and a counter encoded in 16 octets. The counter
* will be modified in each block encryption.
* @param nonce_len Length of the nonce in octets. As nounce and counter
* have to fit in one aligned 16 octet block, maximum
* length of nonce is limited by input_len:
* 16 - log_2(input_len)
* @param input pointer to input data to encrypt
* @param length length of the input data
* @param output pointer to allocated memory for encrypted data. It has
* to be of size data_len.
*/
int cipher_decrypt_ctr(cipher_t* cipher, uint8_t nonce_counter[16],
uint8_t nonce_len, uint8_t* input, size_t length,
uint8_t* output);
#ifdef __cplusplus
}
#endif
#endif /* CRYPTO_MODES_CTR_H */