mirror of https://gerrit.osmocom.org/libosmocore
58 lines
1.9 KiB
C
58 lines
1.9 KiB
C
/*! \file gsm/a5.h
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* Osmocom GSM A5 ciphering algorithm header. */
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/*
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* Copyright (C) 2011 Sylvain Munaut <tnt@246tNt.com>
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*
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#pragma once
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#include <stdint.h>
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#include <osmocom/core/defs.h>
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#include <osmocom/core/bits.h>
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/*! \defgroup a5 GSM A5 ciphering algorithm
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* @{
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* \file a5.h */
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/*! Converts a frame number into the 22 bit number used in A5/x
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* \param[in] fn The true framenumber
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* \return 22 bit word
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*/
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static inline uint32_t
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osmo_a5_fn_count(uint32_t fn)
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{
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int t1 = fn / (26 * 51);
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int t2 = fn % 26;
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int t3 = fn % 51;
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return (t1 << 11) | (t3 << 5) | t2;
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}
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/* Notes:
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* - key must be 8 or 16 (for a5/4) bytes long (or NULL for A5/0)
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* - the dl and ul pointer must be either NULL or 114 bits long
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* - fn is the _real_ GSM frame number.
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* (converted internally to fn_count)
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*/
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int osmo_a5(int n, const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul);
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void osmo_a5_1(const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul) OSMO_DEPRECATED("Use generic osmo_a5() instead");
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void osmo_a5_2(const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul) OSMO_DEPRECATED("Use generic osmo_a5() instead");
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/*! @} */
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