libosmogsm 0.9.6-23.20170220git32ee5af8.fc42
Osmocom GSM library
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a5.h
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1/*
2 * a5.h
3 *
4 * Copyright (C) 2011 Sylvain Munaut <tnt@246tNt.com>
5 *
6 * All Rights Reserved
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License along
19 * with this program; if not, write to the Free Software Foundation, Inc.,
20 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
21 */
22
23#pragma once
24
25#include <stdint.h>
26
27#include <osmocom/core/defs.h>
28#include <osmocom/core/bits.h>
29
42static inline uint32_t
43osmo_a5_fn_count(uint32_t fn)
44{
45 int t1 = fn / (26 * 51);
46 int t2 = fn % 26;
47 int t3 = fn % 51;
48 return (t1 << 11) | (t3 << 5) | t2;
49}
50
51 /* Notes:
52 * - key must be 8 or 16 (for a5/4) bytes long (or NULL for A5/0)
53 * - the dl and ul pointer must be either NULL or 114 bits long
54 * - fn is the _real_ GSM frame number.
55 * (converted internally to fn_count)
56 */
57int osmo_a5(int n, const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul);
58void osmo_a5_1(const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul) OSMO_DEPRECATED("Use generic osmo_a5() instead");
59void osmo_a5_2(const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul) OSMO_DEPRECATED("Use generic osmo_a5() instead");
60
static uint32_t osmo_a5_fn_count(uint32_t fn)
Converts a frame number into the 22 bit number used in A5/x.
Definition a5.h:43
int osmo_a5(int n, const uint8_t *key, uint32_t fn, ubit_t *dl, ubit_t *ul)
Main method to generate a A5/x cipher stream.
Definition a5.c:414