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import more sources from GSM/3GPP spec

This commit is contained in:
Harald Welte 2010-06-30 20:35:02 +02:00
parent c42335fffb
commit 73998b6cf3
5 changed files with 230 additions and 5 deletions
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124
src/a53f.c Normal file
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/*---------------------------------------------------------
* A5/3
*---------------------------------------------------------
*
* A sample implementation of A5/3, the functions of the
* A5/3 algorithm set.
*
* This has been coded for clarity, not necessarily for
* efficiency.
*
* This will compile and run correctly on both Intel
* (little endian) and Sparc (big endian) machines.
*
* Version 0.1 13 March 2002
*
*---------------------------------------------------------*/
#include "kasumi.h"
#include <stdlib.h>
void KGcore( u8 ca, u8 cb, u32 cc, u8 cd, u8 *ck, u8 *co, int cl );
/*---------------------------------------------------------
* BuildKey()
* The KGcore() function expects a 128-bit key. This
* function builds that key from shorter length keys.
*---------------------------------------------------------*/
static u8 *BuildKey( u8 *k, int len )
{
static u8 ck[16]; /* Where the key is built */
int i, n, sf;
u8 mask[]={0x1,0x3,0x7,0xF,0x1F,0x3F,0x7F,0xFF};
i = (len+7)/8; /* Round to nearest byte */
if (i > 16 )
i = 16; /* limit to 128 bits */
for( n=0; n<i; ++n ) /* copy over the key */
ck[n] = k[n];
sf = len%8; /* Any odd key length? */
/* If the key is less than 128-bits we need to replicate *
* it as many times as is necessary to fill the key. */
if( len < 128 )
{
n = 0;
if( sf ) /* Doesn't align to byte boundaries */
{
ck[i-1] &= mask[sf];
ck[i-1] += ck[0]<<sf;
while( i<16 )
{
ck[i] = (ck[n]>>(8-sf)) + (ck[n+1]<<sf);
++n;
++i;
}
}
else
while( i<16 )
ck[i++] = ck[n++];
}
return( ck );
}
/*---------------------------------------------------------
* The basic A5/3 functions.
* These follow a standard layout:
* - From the supplied key build the 128-bit required by
* KGcore()
* - Call the KGcora() function with te appropriate
* parameters
* - Take the generated Keystream and repackage it
* in the required format.
*/
/*---------------------------------------------------------
* The standard GSM function
*---------------------------------------------------------*/
void GSM( u8 *key, int klen, int count, u8 *block1, u8 *block2 )
{
u8 *ck, data[32];
int i;
ck=BuildKey( key, klen );
KGcore( 0x0F, 0, count, 0, ck, data, 228 );
for( i=0; i<15; ++i )
{
block1[i] = data[i];
block2[i] = (data[i+14]<<2) + (data[i+15]>>6);
}
block1[14] &= 0xC0;
block2[14] &= 0xC0;
}
/*---------------------------------------------------------
* The standard GSM ECSD function
*---------------------------------------------------------*/
void ECSD( u8 *key, int klen, int count, u8 *block1, u8 *block2 )
{
u8 *ck, data[87];
int i;
ck=BuildKey( key, klen );
KGcore( 0xF0, 0, count, 0, ck, data, 696 );
for( i=0; i<44; ++i )
{
block1[i] = data[i];
block2[i] = (data[i+43]<<4) + (data[i+44]>>4);
}
block1[43] &= 0xF0;
block2[43] &= 0xF0;
}
/*---------------------------------------------------------
* The standard GEA3 function
*---------------------------------------------------------*/
void GEA3( u8 *key, int klen, u32 input, u8 direction, u8 *block, int m )
{
u8 *ck, *data;
int i;
data = malloc( m );
ck=BuildKey( key, klen );
KGcore( 0xFF, 0, input, direction, ck, data, m*8 );
for( i=0; i<m; ++i )
block[i] = data[i];
free( data );
}
/*---------------------------------------------------------
* E n d o f A 5 3 f . c
*---------------------------------------------------------*/

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#ifndef A53_F_H
#define A53_F_H
void GSM( u8 *key, int klen, int count, u8 *block1, u8 *block2 );
void ECSD( u8 *key, int klen, int count, u8 *block1, u8 *block2 );
void GEA3( u8 *key, int klen, u32 input, u8 direction, u8 *block, int m );
#endif

2
src/kasumi.c
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*
*-----------------------------------------------------------------------*/
#include "Kasumi.h"
#include "kasumi.h"
/*--------- 16 bit rotate left ------------------------------------------*/

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src/kasumi.h
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#ifndef KASUMI_H
#define KASUMI_H
#include <stdint.h>
/*---------------------------------------------------------
* Kasumi.h
* Kasumi.h
*---------------------------------------------------------*/
typedef unsigned char u8;
typedef unsigned short u16;
typedef unsigned int u32;
typedef unsigned char u8;
typedef unsigned short u16;
typedef unsigned long u32;
/*----- a 64-bit structure to help with endian issues -----*/
typedef union {
u32 b32[2];
u16 b16[4];
u8 b8[8];
} REGISTER64;
/*------------- prototypes --------------------------------*/
void KeySchedule( u8 *key );
void Kasumi( u8 *data );
#endif /* KASUMI_H */

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/*---------------------------------------------------------
* KGCORE
*---------------------------------------------------------
*
* A sample implementation of KGCORE, the heart of the
* A5/3 algorithm set.
*
* This has been coded for clarity, not necessarily for
* efficiency.
*
* This will compile and run correctly on both Intel
* (little endian) and Sparc (big endian) machines.
*
* Version 0.1 13 March 2002
*
*---------------------------------------------------------*/
#include "kasumi.h"
#include <stdio.h>
#include <stdint.h>
/*---------------------------------------------------------
* KGcore()
* Given ca, cb, cc, cd, ck, cl generate c0
*---------------------------------------------------------*/
void KGcore( u8 ca, u8 cb, u32 cc, u8 cd, u8 *ck, u8 *co, int cl )
{
REGISTER64 A; /* the modifier */
REGISTER64 temp; /* The working register */
int i, n;
u8 key[16],ModKey[16]; /* Modified key */
u16 blkcnt; /* The block counter */
/* Copy over the key */
for( i=0; i<16; ++i )
key[i] = ck[i];
/* Start by building our global modifier */
temp.b32[0] = temp.b32[1] = 0;
A.b32[0] = A.b32[1] = 0;
/* initialise register in an endian correct manner*/
A.b8[0] = (u8) (cc>>24);
A.b8[1] = (u8) (cc>>16);
A.b8[2] = (u8) (cc>>8);
A.b8[3] = (u8) (cc);
A.b8[4] = (u8) (cb<<3);
A.b8[4] |= (u8) (cd<<2);
A.b8[5] = (u8) ca;
/* Construct the modified key and then "kasumi" A */
for( n=0; n<16; ++n )
ModKey[n] = (u8)(ck[n] ^ 0x55);
KeySchedule( ModKey );
Kasumi( A.b8 ); /* First encryption to create modifier */
/* Final initialisation steps */
blkcnt = 0;
KeySchedule( key );
/* Now run the key stream generator */
while( cl > 0 )
{
/* First we calculate the next 64-bits of keystream */
/* XOR in A and BLKCNT to last value */
temp.b32[0] ^= A.b32[0];
temp.b32[1] ^= A.b32[1];
temp.b8[7] ^= blkcnt;
/* KASUMI it to produce the next block of keystream */
Kasumi( temp.b8 );
/* Set <n> to the number of bytes of input data *
* we have to modify. (=8 if length <= 64) */
if( cl >= 64 )
n = 8;
else
n = (cl+7)/8;
/* copy out the keystream */
for( i=0; i<n; ++i )
*co++ = temp.b8[i];
cl -= 64; /* done another 64 bits */
++blkcnt; /* increment BLKCNT */
}
}
/*-----------------------------------------------------------
* e n d o f K G c o r e . c
*-----------------------------------------------------------*/