idea_lcl.h

是一种简单的算法 在有些编程上是很实际的 希望大家多多支持

/* crypto/idea/idea_lcl.h */
/* Copyright (C) 1995-1998 Eric Young ([e-mail])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([e-mail]).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson ([e-mail]).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young ([e-mail])"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson ([e-mail])"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

/* The new form of this macro (check if the a*b == 0) was suggested by 
 * Colin Plumb <[e-mail]> */
/* Removal of the inner if from from Wei Dai 24/4/96 */
#define idea_mul(r,a,b,ul) \
ul=(unsigned long)a*b; \
if (ul != 0) \
	{ \
	r=(ul&0xffff)-(ul>>16); \
	r-=((r)>>16); \
	} \
else \
	r=(-(int)a-b+1); /* assuming a or b is 0 and in range */ 

#ifdef undef
#define idea_mul(r,a,b,ul,sl) \
if (a == 0) r=(0x10001-b)&0xffff; \
else if (b == 0) r=(0x10001-a)&0xffff; \
else	{ \
	ul=(unsigned long)a*b; \
	sl=(ul&0xffff)-(ul>>16); \
	if (sl <= 0) sl+=0x10001; \
	r=sl; \
	} 
#endif

/*  7/12/95 - Many thanks to Rhys Weatherley <[e-mail]>
 * for pointing out that I was assuming little endian
 * byte order for all quantities what idea
 * actually used bigendian.  No where in the spec does it mention
 * this, it is all in terms of 16 bit numbers and even the example
 * does not use byte streams for the input example :-(.
 * If you byte swap each pair of input, keys and iv, the functions
 * would produce the output as the old version :-(.
 */

/* NOTE - c is not incremented as per n2l */
#define n2ln(c,l1,l2,n)	{ \
			c+=n; \
			l1=l2=0; \
			switch (n) { \
			case 8: l2 =((unsigned long)(*(--(c))))    ; \
			case 7: l2|=((unsigned long)(*(--(c))))<< 8; \
			case 6: l2|=((unsigned long)(*(--(c))))<<16; \
			case 5: l2|=((unsigned long)(*(--(c))))<<24; \
			case 4: l1 =((unsigned long)(*(--(c))))    ; \
			case 3: l1|=((unsigned long)(*(--(c))))<< 8; \
			case 2: l1|=((unsigned long)(*(--(c))))<<16; \
			case 1: l1|=((unsigned long)(*(--(c))))<<24; \
				} \
			}

/* NOTE - c is not incremented as per l2n */
#define l2nn(l1,l2,c,n)	{ \
			c+=n; \
			switch (n) { \
			case 8: *(--(c))=(unsigned char)(((l2)    )&0xff); \
			case 7: *(--(c))=(unsigned char)(((l2)>> 8)&0xff); \
			case 6: *(--(c))=(unsigned char)(((l2)>>16)&0xff); \
			case 5: *(--(c))=(unsigned char)(((l2)>>24)&0xff); \
			case 4: *(--(c))=(unsigned char)(((l1)    )&0xff); \
			case 3: *(--(c))=(unsigned char)(((l1)>> 8)&0xff); \
			case 2: *(--(c))=(unsigned char)(((l1)>>16)&0xff); \
			case 1: *(--(c))=(unsigned char)(((l1)>>24)&0xff); \
				} \
			}

#undef n2l
#define n2l(c,l)        (l =((unsigned long)(*((c)++)))<<24L, \
                         l|=((unsigned long)(*((c)++)))<<16L, \
                         l|=((unsigned long)(*((c)++)))<< 8L, \
                         l|=((unsigned long)(*((c)++))))

#undef l2n
#define l2n(l,c)        (*((c)++)=(unsigned char)(((l)>>24L)&0xff), \
                         *((c)++)=(unsigned char)(((l)>>16L)&0xff), \
                         *((c)++)=(unsigned char)(((l)>> 8L)&0xff), \
                         *((c)++)=(unsigned char)(((l)     )&0xff))

#undef s2n
#define s2n(l,c)	(*((c)++)=(unsigned char)(((l)     )&0xff), \
			 *((c)++)=(unsigned char)(((l)>> 8L)&0xff))

#undef n2s
#define n2s(c,l)	(l =((IDEA_INT)(*((c)++)))<< 8L, \
			 l|=((IDEA_INT)(*((c)++)))      )

#ifdef undef
/* NOTE - c is not incremented as per c2l */
#define c2ln(c,l1,l2,n)	{ \
			c+=n; \
			l1=l2=0; \
			switch (n) { \
			case 8: l2 =((unsigned long)(*(--(c))))<<24; \
			case 7: l2|=((unsigned long)(*(--(c))))<<16; \
			case 6: l2|=((unsigned long)(*(--(c))))<< 8; \
			case 5: l2|=((unsigned long)(*(--(c))));     \
			case 4: l1 =((unsigned long)(*(--(c))))<<24; \
			case 3: l1|=((unsigned long)(*(--(c))))<<16; \
			case 2: l1|=((unsigned long)(*(--(c))))<< 8; \
			case 1: l1|=((unsigned long)(*(--(c))));     \
				} \
			}

/* NOTE - c is not incremented as per l2c */
#define l2cn(l1,l2,c,n)	{ \
			c+=n; \
			switch (n) { \
			case 8: *(--(c))=(unsigned char)(((l2)>>24)&0xff); \
			case 7: *(--(c))=(unsigned char)(((l2)>>16)&0xff); \
			case 6: *(--(c))=(unsigned char)(((l2)>> 8)&0xff); \
			case 5: *(--(c))=(unsigned char)(((l2)    )&0xff); \
			case 4: *(--(c))=(unsigned char)(((l1)>>24)&0xff); \
			case 3: *(--(c))=(unsigned char)(((l1)>>16)&0xff); \
			case 2: *(--(c))=(unsigned char)(((l1)>> 8)&0xff); \
			case 1: *(--(c))=(unsigned char)(((l1)    )&0xff); \
				} \
			}

#undef c2s
#define c2s(c,l)	(l =((unsigned long)(*((c)++)))    , \
			 l|=((unsigned long)(*((c)++)))<< 8L)

#undef s2c
#define s2c(l,c)	(*((c)++)=(unsigned char)(((l)     )&0xff), \
			 *((c)++)=(unsigned char)(((l)>> 8L)&0xff))

#undef c2l
#define c2l(c,l)	(l =((unsigned long)(*((c)++)))     , \
			 l|=((unsigned long)(*((c)++)))<< 8L, \
			 l|=((unsigned long)(*((c)++)))<<16L, \
			 l|=((unsigned long)(*((c)++)))<<24L)

#undef l2c
#define l2c(l,c)	(*((c)++)=(unsigned char)(((l)     )&0xff), \
			 *((c)++)=(unsigned char)(((l)>> 8L)&0xff), \
			 *((c)++)=(unsigned char)(((l)>>16L)&0xff), \
			 *((c)++)=(unsigned char)(((l)>>24L)&0xff))
#endif

#define E_IDEA(num) \
	x1&=0xffff; \
	idea_mul(x1,x1,*p,ul); p++; \
	x2+= *(p++); \
	x3+= *(p++); \
	x4&=0xffff; \
	idea_mul(x4,x4,*p,ul); p++; \
	t0=(x1^x3)&0xffff; \
	idea_mul(t0,t0,*p,ul); p++; \
	t1=(t0+(x2^x4))&0xffff; \
	idea_mul(t1,t1,*p,ul); p++; \
	t0+=t1; \
	x1^=t1; \
	x4^=t0; \
	ul=x2^t0; /* do the swap to x3 */ \
	x2=x3^t1; \
	x3=ul;