| /* |
| * a5.h |
| * |
| * Copyright (C) 2011 Sylvain Munaut <tnt@246tNt.com> |
| * |
| * 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 2 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. |
| */ |
| |
| #ifndef __OSMO_A5_H__ |
| #define __OSMO_A5_H__ |
| |
| #include <stdint.h> |
| |
| #include <osmocom/core/bits.h> |
| |
| /*! \defgroup a5 GSM A5 ciphering algorithm |
| * @{ |
| */ |
| |
| /*! \file gsm/a5.h |
| * \brief Osmocom GSM A5 ciphering algorithm header |
| */ |
| |
| /*! \brief Converts a frame number into the 22 bit number used in A5/x |
| * \param[in] fn The true framenumber |
| * \return 22 bit word |
| */ |
| static inline uint32_t |
| osmo_a5_fn_count(uint32_t fn) |
| { |
| int t1 = fn / (26 * 51); |
| int t2 = fn % 26; |
| int t3 = fn % 51; |
| return (t1 << 11) | (t3 << 5) | t2; |
| } |
| |
| /* Notes: |
| * - key must be 8 bytes long (or NULL for A5/0) |
| * - the dl and ul pointer must be either NULL or 114 bits long |
| * - fn is the _real_ GSM frame number. |
| * (converted internally to fn_count) |
| */ |
| int osmo_a5(int n, const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul); |
| void osmo_a5_1(const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul); |
| void osmo_a5_2(const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul); |
| |
| /*! @} */ |
| |
| #endif /* __OSMO_A5_H__ */ |