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/*! \file gea.c
* Implementation of GEA3 and GEA4. */
/*
* Copyright (C) 2016 by Sysmocom s.f.m.c. GmbH
*
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <osmocom/core/bits.h>
#include <osmocom/crypt/gprs_cipher.h>
#include <osmocom/crypt/auth.h>
#include <osmocom/gsm/kasumi.h>
#include <stdint.h>
#include <string.h>
/*! \addtogroup crypto
* @{
* \file gsm/gea.c */
/*! Performs the GEA4 algorithm as in 3GPP TS 55.226 V9.0.0
* \param[in,out] out Buffer for gamma for encrypted/decrypted
* \param[in] len Length of out, in bytes
* \param[in] kc Buffer with the ciphering key
* \param[in] iv Init vector
* \param[in] direct Direction: 0 (MS -> SGSN) or 1 (SGSN -> MS)
*/
int gea4(uint8_t *out, uint16_t len, uint8_t *kc, uint32_t iv,
enum gprs_cipher_direction direction)
{
_kasumi_kgcore(0xFF, 0, iv, direction, kc, out, len * 8);
return 0;
}
/*! Performs the GEA3 algorithm as in 3GPP TS 55.216 V6.2.0
* \param[in,out] out Buffer for gamma for encrypted/decrypted
* \param[in] len Length of out, in bytes
* \param[in] kc Buffer with the ciphering key
* \param[in] iv Init vector
* \param[in] direct Direction: 0 (MS -> SGSN) or 1 (SGSN -> MS)
*/
int gea3(uint8_t *out, uint16_t len, uint8_t *kc, uint32_t iv,
enum gprs_cipher_direction direction)
{
uint8_t ck[gprs_cipher_key_length(GPRS_ALGO_GEA4)];
osmo_c4(ck, kc);
return gea4(out, len, ck, iv, direction);
}
/*! @} */
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