home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
OS/2 Shareware BBS: 10 Tools
/
10-Tools.zip
/
crypl200.zip
/
IDEA
/
IDEA.C
next >
Wrap
Text File
|
1996-09-22
|
15KB
|
629 lines
#define OPTIMIZE /* Paulo Barreto <pbarreto@unisys.com.br> 1996.01.17 */
/*
* idea.c - C source code for IDEA block cipher.
* IDEA (International Data Encryption Algorithm), formerly known as
* IPES (Improved Proposed Encryption Standard).
* Algorithm developed by Xuejia Lai and James L. Massey, of ETH Zurich.
* This implementation modified and derived from original C code
* developed by Xuejia Lai.
* Zero-based indexing added, names changed from IPES to IDEA.
* CFB functions added. Random number routines added.
*
* Extensively optimized and restructured by Colin Plumb.
*
* There are two adjustments that can be made to this code to
* speed it up. Defaults may be used for PCs. Only the -DIDEA32
* pays off significantly if selectively set or not set.
* Experiment to see what works best for your machine.
*
* Multiplication: default is inline, -DAVOID_JUMPS uses a
* different version that does not do any conditional
* jumps (a few percent worse on a SPARC), while
* -DSMALL_CACHE takes it out of line to stay
* within a small on-chip code cache.
* Variables: normally, 16-bit variables are used, but some
* machines (notably RISCs) do not have 16-bit registers,
* so they do a great deal of masking. -DIDEA32 uses "int"
* register variables and masks explicitly only where
* necessary. On a SPARC, for example, this boosts
* performace by 30%.
*
* The IDEA(tm) block cipher is covered by patents held by ETH and a
* Swiss company called Ascom-Tech AG. The Swiss patent number is
* PCT/CH91/00117, the European patent number is EP 0 482 154 B1, and
* the U.S. patent number is US005214703. IDEA(tm) is a trademark of
* Ascom-Tech AG. There is no license fee required for noncommercial
* use. Commercial users may obtain licensing details from Dieter
* Profos, Ascom Tech AG, Solothurn Lab, Postfach 151, 4502 Solothurn,
* Switzerland, Tel +41 65 242885, Fax +41 65 235761.
*
* The IDEA block cipher uses a 64-bit block size, and a 128-bit key
* size. It breaks the 64-bit cipher block into four 16-bit words
* because all of the primitive inner operations are done with 16-bit
* arithmetic. It likewise breaks the 128-bit cipher key into eight
* 16-bit words.
*
* For further information on the IDEA cipher, see the book:
* Xuejia Lai, "On the Design and Security of Block Ciphers",
* ETH Series on Information Processing (ed. J.L. Massey) Vol 1,
* Hartung-Gorre Verlag, Konstanz, Switzerland, 1992. ISBN
* 3-89191-573-X.
*
* This code runs on arrays of bytes by taking pairs in big-endian
* order to make the 16-bit words that IDEA uses internally. This
* produces the same result regardless of the byte order of the
* native CPU.
*/
#include <string.h>
#if defined( INC_ALL )
#include "crypt.h"
#include "idea.h"
#elif defined( INC_CHILD )
#include "../crypt.h"
#include "idea.h"
#else
#include "crypt.h"
#include "idea/idea.h"
#endif /* Compiler-specific includes */
#ifdef BIG_ENDIAN /* This code uses slightly different names */
#define HIGHFIRST
#endif /* BIG_ENDIAN */
#ifdef IDEA32 /* Use >16-bit temporaries */
#define low16(x) ((x) & 0xFFFF)
typedef unsigned int uint16; /* at LEAST 16 bits, maybe more */
#else
#define low16(x) (x) /* this is only ever applied to uint16's */
typedef word16 uint16;
#endif
#ifdef _GNUC_
/* __const__ simply means there are no side effects for this function,
* which is useful info for the gcc optimizer
*/
#define CONST __const__
#else
#define CONST
#endif
/*
* Multiplication, modulo (2**16)+1
* Note that this code is structured on the assumption that
* untaken branches are cheaper than taken branches, and the
* compiler doesn't schedule branches.
*/
#ifdef SMALL_CACHE
CONST static uint16
mul(register uint16 a, register uint16 b)
{
register word32 p;
p = (word32)a * b;
if (p) {
b = low16(p);
a = p>>16;
return (b - a) + (b < a);
} else if (a) {
return 1-b;
} else {
return 1-a;
}
} /* mul */
#endif /* SMALL_CACHE */
/*
* Compute the multiplicative inverse of x, modulo 65537, using Euclid's
* algorithm. It is unrolled twice to avoid swapping the registers each
* iteration, and some subtracts of t have been changed to adds.
*/
CONST static uint16
mulInv(uint16 x)
{
uint16 t0, t1;
uint16 q, y;
if (x <= 1)
return x; /* 0 and 1 are self-inverse */
t1 = 0x10001L / x; /* Since x >= 2, this fits into 16 bits */
y = 0x10001L % x;
if (y == 1)
return ( uint16 ) low16(1-t1);
t0 = 1;
do {
q = x / y;
x = x % y;
t0 += q * t1;
if (x == 1)
return t0;
q = y / x;
y = y % x;
t1 += q * t0;
} while (y != 1);
return ( uint16 ) low16(1-t1);
} /* mukInv */
/*
* Expand a 128-bit user key to a working encryption key EK
*/
void
ideaExpandKey(byte const *userkey, word16 *EK)
{
int i,j;
for (j=0; j<8; j++) {
EK[j] = (userkey[0]<<8) + userkey[1];
userkey += 2;
}
for (i=0; j < IDEAKEYLEN; j++) {
i++;
EK[i+7] = (EK[i & 7] << 9) | (EK[i+1 & 7] >> 7);
EK += i & 8;
i &= 7;
}
} /* ideaExpandKey */
#define NEG(x) (- (int) (x))
/*
* Compute IDEA decryption key DK from an expanded IDEA encryption key EK
* Note that the input and output may be the same. Thus, the key is
* inverted into an internal buffer, and then copied to the output.
*/
void
#ifdef _DCC
ideaInvertKey(word16 *EK, word16 DK[IDEAKEYLEN])
#else
ideaInvertKey(word16 const *EK, word16 DK[IDEAKEYLEN])
#endif
{
word16 temp[IDEAKEYLEN];
#ifdef OPTIMIZE
register int k, p, r;
p = IDEAKEYLEN;
temp [p-1] = mulInv (EK [3]);
temp [p-2] = NEG (EK [2]);
temp [p-3] = NEG (EK [1]);
temp [p-4] = mulInv (EK [0]);
k = 4; p -= 4;
for (r = IDEAROUNDS - 1; r > 0; r--) {
temp [p-1] = EK [k+1];
temp [p-2] = EK [k];
temp [p-3] = mulInv (EK [k+5]);
temp [p-4] = NEG (EK [k+3]);
temp [p-5] = NEG (EK [k+4]);
temp [p-6] = mulInv (EK [k+2]);
k += 6; p -= 6;
}
temp [p-1] = EK [k+1];
temp [p-2] = EK [k];
temp [p-3] = mulInv (EK [k+5]);
temp [p-4] = NEG (EK [k+4]);
temp [p-5] = NEG (EK [k+3]);
temp [p-6] = mulInv (EK [k+2]);
#else /* !OPTIMIZE */
int i;
uint16 t1, t2, t3;
word16 *p = temp + IDEAKEYLEN;
t1 = mulInv(*EK++);
t2 = - ( int ) *EK++;
t3 = - ( int ) *EK++;
*--p = mulInv(*EK++);
*--p = t3;
*--p = t2;
*--p = t1;
for (i = 0; i < IDEAROUNDS-1; i++) {
t1 = *EK++;
*--p = *EK++;
*--p = t1;
t1 = mulInv(*EK++);
t2 = - ( int ) *EK++;
t3 = - ( int ) *EK++;
*--p = mulInv(*EK++);
*--p = t2;
*--p = t3;
*--p = t1;
}
t1 = *EK++;
*--p = *EK++;
*--p = t1;
t1 = mulInv(*EK++);
t2 = - ( int ) *EK++;
t3 = - ( int ) *EK++;
*--p = mulInv(*EK++);
*--p = t3;
*--p = t2;
*--p = t1;
#endif /* ?OPTIMIZE */
/* Copy and destroy temp copy */
memcpy(DK, temp, sizeof(temp));
burn(temp);
} /* ideaInvertKey */
/*
* MUL(x,y) computes x = x*y, modulo 0x10001. Requires two temps,
* t16 and t32. x is modified, and must me a side-effect-free lvalue.
* y may be anything, but unlike x, must be strictly 16 bits even if
* low16() is #defined.
* All of these are equivalent - see which is faster on your machine
*/
#ifdef SMALL_CACHE
#define MUL(x,y) (x = mul(low16(x),y))
#else /* !SMALL_CACHE */
#ifdef AVOID_JUMPS
#define MUL(x,y) (x = low16(x-1), t16 = low16((y)-1), \
t32 = (word32)x*t16 + x + t16 + 1, x = low16(t32), \
t16 = t32>>16, x = (x-t16) + (x<t16) )
#else /* !AVOID_JUMPS (default) */
#define MUL(x,y) \
((t16 = (y)) ? \
(x=low16(x)) ? \
t32 = (word32)x*t16, \
x = low16(t32), \
t16 = t32>>16, \
x = (x-t16)+(x<t16) \
: \
(x = 1-t16) \
: \
(x = 1-x))
#endif
#endif
/* IDEA encryption/decryption algorithm */
/* Note that in and out can be the same buffer */
void
#ifdef _DCC
ideaCipher(byte (inbuf[8]), byte (outbuf[8]), word16 *key)
#else
ideaCipher(byte const (inbuf[8]), byte (outbuf[8]), word16 const *key)
#endif
{
register uint16 x1, x2, x3, x4, s2, s3;
word16 *in, *out;
#ifndef SMALL_CACHE
register uint16 t16; /* Temporaries needed by MUL macro */
register word32 t32;
#endif
#ifndef OPTIMIZE
int r = IDEAROUNDS;
#endif /* ?OPTIMIZE */
in = (word16 *)inbuf;
#ifdef OPTIMIZE
x1 = in[0]; x2 = in[1];
x3 = in[2]; x4 = in[3];
#else /* !OPTIMIZE */
x1 = *in++; x2 = *in++;
x3 = *in++; x4 = *in;
#endif /* ?OPTIMIZE */
#ifndef HIGHFIRST
x1 = (x1>>8) | (x1<<8);
x2 = (x2>>8) | (x2<<8);
x3 = (x3>>8) | (x3<<8);
x4 = (x4>>8) | (x4<<8);
#endif
#ifdef OPTIMIZE
/* round 1: */
MUL(x1,key[0]);
x2 += key[1];
x3 += key[2];
MUL(x4, key[3]);
s3 = x3;
x3 ^= x1;
MUL(x3, key[4]);
s2 = x2;
x2 ^= x4;
x2 += x3;
MUL(x2, key[5]);
x3 += x2;
x1 ^= x2; x4 ^= x3;
x2 ^= s3; x3 ^= s2;
/* round 2: */
MUL(x1,key[6]);
x2 += key[7];
x3 += key[8];
MUL(x4, key[9]);
s3 = x3;
x3 ^= x1;
MUL(x3, key[10]);
s2 = x2;
x2 ^= x4;
x2 += x3;
MUL(x2, key[11]);
x3 += x2;
x1 ^= x2; x4 ^= x3;
x2 ^= s3; x3 ^= s2;
/* round 3: */
MUL(x1,key[12]);
x2 += key[13];
x3 += key[14];
MUL(x4, key[15]);
s3 = x3;
x3 ^= x1;
MUL(x3, key[16]);
s2 = x2;
x2 ^= x4;
x2 += x3;
MUL(x2, key[17]);
x3 += x2;
x1 ^= x2; x4 ^= x3;
x2 ^= s3; x3 ^= s2;
/* round 4: */
MUL(x1,key[18]);
x2 += key[19];
x3 += key[20];
MUL(x4, key[21]);
s3 = x3;
x3 ^= x1;
MUL(x3, key[22]);
s2 = x2;
x2 ^= x4;
x2 += x3;
MUL(x2, key[23]);
x3 += x2;
x1 ^= x2; x4 ^= x3;
x2 ^= s3; x3 ^= s2;
/* round 5: */
MUL(x1,key[24]);
x2 += key[25];
x3 += key[26];
MUL(x4, key[27]);
s3 = x3;
x3 ^= x1;
MUL(x3, key[28]);
s2 = x2;
x2 ^= x4;
x2 += x3;
MUL(x2, key[29]);
x3 += x2;
x1 ^= x2; x4 ^= x3;
x2 ^= s3; x3 ^= s2;
/* round 6: */
MUL(x1,key[30]);
x2 += key[31];
x3 += key[32];
MUL(x4, key[33]);
s3 = x3;
x3 ^= x1;
MUL(x3, key[34]);
s2 = x2;
x2 ^= x4;
x2 += x3;
MUL(x2, key[35]);
x3 += x2;
x1 ^= x2; x4 ^= x3;
x2 ^= s3; x3 ^= s2;
/* round 7: */
MUL(x1,key[36]);
x2 += key[37];
x3 += key[38];
MUL(x4, key[39]);
s3 = x3;
x3 ^= x1;
MUL(x3, key[40]);
s2 = x2;
x2 ^= x4;
x2 += x3;
MUL(x2, key[41]);
x3 += x2;
x1 ^= x2; x4 ^= x3;
x2 ^= s3; x3 ^= s2;
/* round 8: */
MUL(x1,key[42]);
x2 += key[43];
x3 += key[44];
MUL(x4, key[45]);
s3 = x3;
x3 ^= x1;
MUL(x3, key[46]);
s2 = x2;
x2 ^= x4;
x2 += x3;
MUL(x2, key[47]);
x3 += x2;
x1 ^= x2; x4 ^= x3;
x2 ^= s3; x3 ^= s2;
/* final semiround: */
MUL(x1, key[48]);
x3 += key[49];
x2 += key[50];
MUL(x4, key[51]);
#else /* !OPTIMIZE */
do {
MUL(x1,*key++);
x2 += *key++;
x3 += *key++;
MUL(x4, *key++);
s3 = x3;
x3 ^= x1;
MUL(x3, *key++);
s2 = x2;
x2 ^= x4;
x2 += x3;
MUL(x2, *key++);
x3 += x2;
x1 ^= x2; x4 ^= x3;
x2 ^= s3; x3 ^= s2;
} while (--r);
MUL(x1, *key++);
x3 += *key++;
x2 += *key++;
MUL(x4, *key);
#endif /* ?OPTIMIZE */
out = (word16 *)outbuf;
#ifdef HIGHFIRST
*out++ = x1;
*out++ = x3;
*out++ = x2;
*out = x4;
#else /* !HIGHFIRST */
#ifdef OPTIMIZE
out[0] = (x1>>8) | (x1<<8);
out[1] = (x3>>8) | (x3<<8);
out[2] = (x2>>8) | (x2<<8);
out[3] = (x4>>8) | (x4<<8);
#else /* !OPTIMIZE */
x1 = low16(x1);
x2 = low16(x2);
x3 = low16(x3);
x4 = low16(x4);
*out++ = (x1>>8) | (x1<<8);
*out++ = (x3>>8) | (x3<<8);
*out++ = (x2>>8) | (x2<<8);
*out = (x4>>8) | (x4<<8);
#endif /* ?OPTIMIZE */
#endif
} /* ideaCipher */
/*-------------------------------------------------------------*/
#ifdef TEST
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
/*
* This is the number of Kbytes of test data to encrypt.
* It defaults to 1 MByte.
*/
#ifndef BLOCKS
#ifndef KBYTES
#define KBYTES 1024L
#endif
#define BLOCKS (64*KBYTES)
#endif
int
main(void)
{ /* Test driver for IDEA cipher */
int i, j, k;
byte userkey[16];
word16 EK[IDEAKEYLEN], DK[IDEAKEYLEN];
byte XX[8], YY[8], ZZ[8];
clock_t start, end;
long l;
float secs;
/* Make a sample user key for testing... */
for(i=0; i<16; i++)
userkey[i] = i+1;
/* Compute encryption subkeys from user key... */
ideaExpandKey(userkey, EK);
printf("\nEncryption key subblocks: ");
for (j=0; j<IDEAROUNDS+1; j++) {
printf("\nround %d: ", j+1);
if (j < IDEAROUNDS)
for(i=0; i<6; i++)
printf(" %6u", EK[j*6+i]);
else
for(i=0; i<4; i++)
printf(" %6u", EK[j*6+i]);
}
/* Compute decryption subkeys from encryption subkeys... */
ideaInvertKey(EK, DK);
printf("\nDecryption key subblocks: ");
for (j=0; j<IDEAROUNDS+1; j++) {
printf("\nround %d: ", j+1);
if (j < IDEAROUNDS)
for(i=0; i<6; i++)
printf(" %6u", DK[j*6+i]);
else
for(i=0; i<4; i++)
printf(" %6u", DK[j*6+i]);
}
/* Make a sample plaintext pattern for testing... */
for (k=0; k<8; k++)
XX[k] = k;
printf("\nEncrypting %ld bytes (%ld blocks)...", BLOCKS*16, BLOCKS);
fflush(stdout);
start = clock();
memcpy(YY, XX, 8);
for (l = 0; l < BLOCKS; l++)
ideaCipher(YY, YY, EK); /* repeated encryption */
memcpy(ZZ, YY, 8);
for (l = 0; l < BLOCKS; l++)
ideaCipher(ZZ, ZZ, DK); /* repeated decryption */
end = clock() - start;
/*
l = end / (CLOCKS_PER_SEC/1000) + 1;
i = l/1000;
j = l%1000;
l = (16 * BLOCKS * (CLOCKS_PER_SEC/1000)) / (end/1000);
printf("%d.%03d seconds = %ld bytes per second\n", i, j, l);
*/
secs = (float) end / CLOCKS_PER_SEC;
printf("%.2f sec = %.0f bytes/sec.\n",
secs, (float) BLOCKS*16 / secs);
printf("\nX %3u %3u %3u %3u %3u %3u %3u %3u\n",
XX[0], XX[1], XX[2], XX[3], XX[4], XX[5], XX[6], XX[7]);
printf("\nY %3u %3u %3u %3u %3u %3u %3u %3u\n",
YY[0], YY[1], YY[2], YY[3], YY[4], YY[5], YY[6], YY[7]);
printf("\nZ %3u %3u %3u %3u %3u %3u %3u %3u\n",
ZZ[0], ZZ[1], ZZ[2], ZZ[3], ZZ[4], ZZ[5], ZZ[6], ZZ[7]);
/* Now decrypted ZZ should be same as original XX */
for (k=0; k<8; k++)
if (XX[k] != ZZ[k]) {
printf("\n\07Error! Noninvertable encryption.\n");
exit(-1); /* error exit */
}
printf("\nNormal exit.\n");
return 0; /* normal exit */
} /* main */
#endif /* TEST */
/* end of idea.c */