48 lines
910 B
C
48 lines
910 B
C
/*
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* File: A5_1.h
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* Author: Daniel Otte
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* Date: 24.06.2006
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* License: GPL
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* Description: Implementation of the A5/1 stream cipher algorithm, as used in GSM.
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* ! Warning, this is weak crypto !
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*
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*/
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#ifndef A5_1_H_
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#define A5_1_H_
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#include <stdint.h>
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#define R1_LENGTH 19
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#define R2_LENGTH 22
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#define R3_LENGTH 23
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#define R1_CLK 11
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#define R2_CLK 12
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#define R3_CLK 13
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/* 3-Bit word parity lookup table (Byte)
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* 0: 0
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* 1: 1
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* 2: 1
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* 3: 0
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* 4: 1
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* 5: 0
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* 6: 0
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* 7: 1
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* => 1001.0110 = 0x96
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*
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*/
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#define PARITY_LOOKUP 0x96
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typedef struct {
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/* we are wasting one byte here but this allows a much faster implementation */
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uint8_t r1[3], r2[3], r3[3]; /* the three regs, 19,22,23 bit in length */
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} a5_1_ctx_t;
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void a5_1_init(a5_1_ctx_t *c, void* key, uint8_t keylength_b, void* iv, uint8_t ivlength_b);
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uint8_t a5_1_clock(a5_1_ctx_t *c);
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uint8_t a5_1_gen(a5_1_ctx_t *c);
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#endif
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