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b1eac93431
* cipher/idea.c: New. Take from Libgcrypt master and adjust for direct use in GnuPG. * cipher/idea-stub.c: Remove. * cipher/Makefile.am: Add idea.c and remove idea-stub.c rules. * configure.ac: Remove idea-stub code. * g10/gpg.c (check_permissions): Remove code path for ITEM==2. (main): Make --load-extension a dummy option. * g10/keygen.c (keygen_set_std_prefs): Include IDEA only in PGP2 compatibility mode. * g10/misc.c (idea_cipher_warn): Remove. Also remove all callers. * g10/seckey-cert.c (do_check): Remove emitting of STATUS_RSA_OR_IDEA. * g10/status.c (get_status_string): Remove STATUS_RSA_OR_IDEA. * g10/status.h (STATUS_RSA_OR_IDEA): Remove. -- To keep the number of actually used algorithms low, we support IDEA only in a basically read-only way (unless --pgp2 is used during key generation). It does not make sense to suggest the use of this old 64 bit blocksize algorithm. However, there is old data available where it might be helpful to have IDEA available.
412 lines
10 KiB
C
412 lines
10 KiB
C
/* idea.c - IDEA function
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* Copyright (c) 1997, 1998, 1999, 2001 by Werner Koch (dd9jn)
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* WERNER KOCH BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* Except as contained in this notice, the name of Werner Koch shall not be
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* used in advertising or otherwise to promote the sale, use or other dealings
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* in this Software without prior written authorization from Werner Koch.
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*
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* Patents on IDEA have expired:
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* Europe: EP0482154 on 2011-05-16,
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* Japan: JP3225440 on 2011-05-16,
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* U.S.: 5,214,703 on 2012-01-07.
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*/
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/*
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* Please see http://www.noepatents.org/ to learn why software patents
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* are bad for society and what you can do to fight them.
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*
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* The code herein is based on the one from:
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* Bruce Schneier: Applied Cryptography. John Wiley & Sons, 1996.
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* ISBN 0-471-11709-9.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include "types.h" /* for byte and u32 typedefs */
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#include "util.h"
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#include "errors.h"
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#include "algorithms.h"
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#define FNCCAST_SETKEY(f) ((int(*)(void*, byte*, unsigned int))(f))
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#define FNCCAST_CRYPT(f) ((void(*)(void*, byte*, byte*))(f))
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#define CIPHER_ALGO_IDEA 1
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#define IDEA_KEYSIZE 16
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#define IDEA_BLOCKSIZE 8
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#define IDEA_ROUNDS 8
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#define IDEA_KEYLEN (6*IDEA_ROUNDS+4)
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typedef struct {
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u16 ek[IDEA_KEYLEN];
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u16 dk[IDEA_KEYLEN];
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int have_dk;
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} IDEA_context;
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static const char *selftest(void);
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static void
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burn_stack (int bytes)
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{
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char buf[64];
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wipememory(buf,sizeof buf);
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bytes -= sizeof buf;
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if (bytes > 0)
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burn_stack (bytes);
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}
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static u16
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mul_inv( u16 x )
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{
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u16 t0, t1;
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u16 q, y;
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if( x < 2 )
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return x;
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t1 = 0x10001L / x;
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y = 0x10001L % x;
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if( y == 1 )
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return (1-t1) & 0xffff;
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t0 = 1;
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do {
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q = x / y;
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x = x % y;
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t0 += q * t1;
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if( x == 1 )
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return t0;
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q = y / x;
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y = y % x;
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t1 += q * t0;
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} while( y != 1 );
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return (1-t1) & 0xffff;
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}
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static void
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expand_key( const byte *userkey, u16 *ek )
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{
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int i,j;
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for(j=0; j < 8; j++ ) {
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ek[j] = (*userkey << 8) + userkey[1];
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userkey += 2;
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}
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for(i=0; j < IDEA_KEYLEN; j++ ) {
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i++;
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ek[i+7] = ek[i&7] << 9 | ek[(i+1)&7] >> 7;
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ek += i & 8;
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i &= 7;
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}
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}
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static void
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invert_key( u16 *ek, u16 dk[IDEA_KEYLEN] )
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{
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int i;
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u16 t1, t2, t3;
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u16 temp[IDEA_KEYLEN];
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u16 *p = temp + IDEA_KEYLEN;
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t1 = mul_inv( *ek++ );
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t2 = -*ek++;
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t3 = -*ek++;
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*--p = mul_inv( *ek++ );
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*--p = t3;
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*--p = t2;
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*--p = t1;
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for(i=0; i < IDEA_ROUNDS-1; i++ ) {
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t1 = *ek++;
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*--p = *ek++;
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*--p = t1;
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t1 = mul_inv( *ek++ );
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t2 = -*ek++;
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t3 = -*ek++;
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*--p = mul_inv( *ek++ );
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*--p = t2;
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*--p = t3;
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*--p = t1;
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}
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t1 = *ek++;
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*--p = *ek++;
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*--p = t1;
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t1 = mul_inv( *ek++ );
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t2 = -*ek++;
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t3 = -*ek++;
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*--p = mul_inv( *ek++ );
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*--p = t3;
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*--p = t2;
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*--p = t1;
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memcpy(dk, temp, sizeof(temp) );
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wipememory(temp, sizeof(temp) ); /* burn temp */
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}
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static void
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cipher( byte *outbuf, const byte *inbuf, u16 *key )
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{
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u16 x1, x2, x3,x4, s2, s3;
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u16 *in, *out;
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int r = IDEA_ROUNDS;
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#define MUL(x,y) \
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do {u16 _t16; u32 _t32; \
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if( (_t16 = (y)) ) { \
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if( (x = (x)&0xffff) ) { \
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_t32 = (u32)x * _t16; \
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x = _t32 & 0xffff; \
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_t16 = _t32 >> 16; \
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x = ((x)-_t16) + (x<_t16?1:0); \
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} \
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else { \
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x = 1 - _t16; \
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} \
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} \
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else { \
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x = 1 - x; \
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} \
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} while(0)
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in = (u16*)inbuf;
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x1 = *in++;
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x2 = *in++;
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x3 = *in++;
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x4 = *in;
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#ifndef WORDS_BIGENDIAN
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x1 = (x1>>8) | (x1<<8);
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x2 = (x2>>8) | (x2<<8);
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x3 = (x3>>8) | (x3<<8);
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x4 = (x4>>8) | (x4<<8);
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#endif
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do {
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MUL(x1, *key++);
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x2 += *key++;
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x3 += *key++;
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MUL(x4, *key++ );
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s3 = x3;
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x3 ^= x1;
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MUL(x3, *key++);
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s2 = x2;
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x2 ^=x4;
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x2 += x3;
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MUL(x2, *key++);
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x3 += x2;
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x1 ^= x2;
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x4 ^= x3;
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x2 ^= s3;
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x3 ^= s2;
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} while( --r );
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MUL(x1, *key++);
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x3 += *key++;
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x2 += *key++;
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MUL(x4, *key);
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out = (u16*)outbuf;
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#ifndef WORDS_BIGENDIAN
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*out++ = (x1>>8) | (x1<<8);
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*out++ = (x3>>8) | (x3<<8);
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*out++ = (x2>>8) | (x2<<8);
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*out = (x4>>8) | (x4<<8);
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#else
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*out++ = x1;
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*out++ = x3;
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*out++ = x2;
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*out = x4;
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#endif
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#undef MUL
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}
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static int
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do_setkey( IDEA_context *c, const byte *key, unsigned int keylen )
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{
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static int initialized = 0;
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static const char *selftest_failed = 0;
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if( !initialized ) {
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initialized = 1;
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selftest_failed = selftest();
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if( selftest_failed )
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log_error( "%s\n", selftest_failed );
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}
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if( selftest_failed )
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return G10ERR_SELFTEST_FAILED;
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assert(keylen == 16);
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c->have_dk = 0;
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expand_key( key, c->ek );
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invert_key( c->ek, c->dk );
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return 0;
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}
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static int
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idea_setkey (void *context, const byte *key, unsigned int keylen)
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{
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IDEA_context *ctx = context;
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int rc = do_setkey (ctx, key, keylen);
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burn_stack (23+6*sizeof(void*));
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return rc;
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}
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static void
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encrypt_block( IDEA_context *c, byte *outbuf, const byte *inbuf )
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{
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cipher( outbuf, inbuf, c->ek );
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}
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static void
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idea_encrypt (void *context, byte *out, const byte *in)
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{
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IDEA_context *ctx = context;
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encrypt_block (ctx, out, in);
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burn_stack (24+3*sizeof (void*));
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}
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static void
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decrypt_block( IDEA_context *c, byte *outbuf, const byte *inbuf )
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{
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if( !c->have_dk ) {
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c->have_dk = 1;
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invert_key( c->ek, c->dk );
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}
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cipher( outbuf, inbuf, c->dk );
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}
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static void
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idea_decrypt (void *context, byte *out, const byte *in)
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{
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IDEA_context *ctx = context;
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decrypt_block (ctx, out, in);
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burn_stack (24+3*sizeof (void*));
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}
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static const char *
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selftest( void )
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{
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static struct {
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byte key[16];
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byte plain[8];
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byte cipher[8];
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} test_vectors[] = {
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{ { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
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0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 },
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{ 0x00, 0x00, 0x00, 0x01, 0x00, 0x02, 0x00, 0x03 },
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{ 0x11, 0xFB, 0xED, 0x2B, 0x01, 0x98, 0x6D, 0xE5 } },
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{ { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
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0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 },
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{ 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 },
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{ 0x54, 0x0E, 0x5F, 0xEA, 0x18, 0xC2, 0xF8, 0xB1 } },
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{ { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
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0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 },
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{ 0x00, 0x19, 0x32, 0x4B, 0x64, 0x7D, 0x96, 0xAF },
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{ 0x9F, 0x0A, 0x0A, 0xB6, 0xE1, 0x0C, 0xED, 0x78 } },
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{ { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
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0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 },
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{ 0xF5, 0x20, 0x2D, 0x5B, 0x9C, 0x67, 0x1B, 0x08 },
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{ 0xCF, 0x18, 0xFD, 0x73, 0x55, 0xE2, 0xC5, 0xC5 } },
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{ { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
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0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 },
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{ 0xFA, 0xE6, 0xD2, 0xBE, 0xAA, 0x96, 0x82, 0x6E },
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{ 0x85, 0xDF, 0x52, 0x00, 0x56, 0x08, 0x19, 0x3D } },
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{ { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
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0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 },
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{ 0x0A, 0x14, 0x1E, 0x28, 0x32, 0x3C, 0x46, 0x50 },
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{ 0x2F, 0x7D, 0xE7, 0x50, 0x21, 0x2F, 0xB7, 0x34 } },
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{ { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
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0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 },
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{ 0x05, 0x0A, 0x0F, 0x14, 0x19, 0x1E, 0x23, 0x28 },
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{ 0x7B, 0x73, 0x14, 0x92, 0x5D, 0xE5, 0x9C, 0x09 } },
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{ { 0x00, 0x05, 0x00, 0x0A, 0x00, 0x0F, 0x00, 0x14,
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0x00, 0x19, 0x00, 0x1E, 0x00, 0x23, 0x00, 0x28 },
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{ 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 },
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{ 0x3E, 0xC0, 0x47, 0x80, 0xBE, 0xFF, 0x6E, 0x20 } },
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{ { 0x3A, 0x98, 0x4E, 0x20, 0x00, 0x19, 0x5D, 0xB3,
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0x2E, 0xE5, 0x01, 0xC8, 0xC4, 0x7C, 0xEA, 0x60 },
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{ 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 },
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{ 0x97, 0xBC, 0xD8, 0x20, 0x07, 0x80, 0xDA, 0x86 } },
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{ { 0x00, 0x64, 0x00, 0xC8, 0x01, 0x2C, 0x01, 0x90,
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0x01, 0xF4, 0x02, 0x58, 0x02, 0xBC, 0x03, 0x20 },
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{ 0x05, 0x32, 0x0A, 0x64, 0x14, 0xC8, 0x19, 0xFA },
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{ 0x65, 0xBE, 0x87, 0xE7, 0xA2, 0x53, 0x8A, 0xED } },
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{ { 0x9D, 0x40, 0x75, 0xC1, 0x03, 0xBC, 0x32, 0x2A,
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0xFB, 0x03, 0xE7, 0xBE, 0x6A, 0xB3, 0x00, 0x06 },
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{ 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08 },
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{ 0xF5, 0xDB, 0x1A, 0xC4, 0x5E, 0x5E, 0xF9, 0xF9 } }
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};
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IDEA_context c;
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byte buffer[8];
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int i;
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for(i=0; i < DIM(test_vectors); i++ ) {
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do_setkey( &c, test_vectors[i].key, 16 );
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encrypt_block( &c, buffer, test_vectors[i].plain );
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if( memcmp( buffer, test_vectors[i].cipher, 8 ) )
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return "IDEA test encryption failed.";
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decrypt_block( &c, buffer, test_vectors[i].cipher );
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if( memcmp( buffer, test_vectors[i].plain, 8 ) )
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return "IDEA test decryption failed.";
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}
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return NULL;
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}
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/****************
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* Return some information about the algorithm. We need algo here to
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* distinguish different flavors of the algorithm.
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* Returns: A pointer to string describing the algorithm or NULL if
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* the ALGO is invalid.
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*/
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const char *
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idea_get_info( int algo, size_t *keylen,
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size_t *blocksize, size_t *contextsize,
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int (**r_setkey)( void *c, const byte *key, unsigned keylen ),
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void (**r_encrypt)( void *c, byte *outbuf, const byte *inbuf ),
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void (**r_decrypt)( void *c, byte *outbuf, const byte *inbuf )
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)
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{
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*keylen = 128;
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*blocksize = IDEA_BLOCKSIZE;
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*contextsize = sizeof(IDEA_context);
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*r_setkey = idea_setkey;
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*r_encrypt = idea_encrypt;
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*r_decrypt = idea_decrypt;
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if( algo == CIPHER_ALGO_IDEA )
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return "IDEA";
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return NULL;
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}
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