/* Sofware DES functions * written 12 Dec 1986 by Phil Karn, KA9Q; large sections adapted from * the 1977 public-domain program by Jim Gillogly * Modified for additional speed - 6 December 1988 Phil Karn * Modified for parameterized key schedules - Jan 1991 Phil Karn * Callers now allocate a key schedule as follows: *	kn = (char (*)[8])malloc(sizeof(char) * 8 * 16); *	or *	char kn[16][8]; */#define	NULL	0#ifdef	LITTLE_ENDIANstatic long byteswap();#endifstatic void permute(),perminit(),spinit();static long f();/* Tables defined in the Data Encryption Standard documents *//* initial permutation IP */static char ip[] = {	58, 50, 42, 34, 26, 18, 10,  2,	60, 52, 44, 36, 28, 20, 12,  4,	62, 54, 46, 38, 30, 22, 14,  6,	64, 56, 48, 40, 32, 24, 16,  8,	57, 49, 41, 33, 25, 17,  9,  1,	59, 51, 43, 35, 27, 19, 11,  3,	61, 53, 45, 37, 29, 21, 13,  5,	63, 55, 47, 39, 31, 23, 15,  7};/* final permutation IP^-1 */static char fp[] = {	40,  8, 48, 16, 56, 24, 64, 32,	39,  7, 47, 15, 55, 23, 63, 31,	38,  6, 46, 14, 54, 22, 62, 30,	37,  5, 45, 13, 53, 21, 61, 29,	36,  4, 44, 12, 52, 20, 60, 28,	35,  3, 43, 11, 51, 19, 59, 27,	34,  2, 42, 10, 50, 18, 58, 26,	33,  1, 41,  9, 49, 17, 57, 25};/* expansion operation matrix * This is for reference only; it is unused in the code * as the f() function performs it implicitly for speed */#ifdef notdefstatic char ei[] = {	32,  1,  2,  3,  4,  5,	 4,  5,  6,  7,  8,  9,	 8,  9, 10, 11, 12, 13,	12, 13, 14, 15, 16, 17,	16, 17, 18, 19, 20, 21,	20, 21, 22, 23, 24, 25,	24, 25, 26, 27, 28, 29,	28, 29, 30, 31, 32,  1 };#endif/* permuted choice table (key) */static char pc1[] = {	57, 49, 41, 33, 25, 17,  9,	 1, 58, 50, 42, 34, 26, 18,	10,  2, 59, 51, 43, 35, 27,	19, 11,  3, 60, 52, 44, 36,	63, 55, 47, 39, 31, 23, 15,	 7, 62, 54, 46, 38, 30, 22,	14,  6, 61, 53, 45, 37, 29,	21, 13,  5, 28, 20, 12,  4};/* number left rotations of pc1 */static char totrot[] = {	1,2,4,6,8,10,12,14,15,17,19,21,23,25,27,28};/* permuted choice key (table) */static char pc2[] = {	14, 17, 11, 24,  1,  5,	 3, 28, 15,  6, 21, 10,	23, 19, 12,  4, 26,  8,	16,  7, 27, 20, 13,  2,	41, 52, 31, 37, 47, 55,	30, 40, 51, 45, 33, 48,	44, 49, 39, 56, 34, 53,	46, 42, 50, 36, 29, 32};/* The (in)famous S-boxes */static char si[8][64] = {	/* S1 */	14,  4, 13,  1,  2, 15, 11,  8,  3, 10,  6, 12,  5,  9,  0,  7,	 0, 15,  7,  4, 14,  2, 13,  1, 10,  6, 12, 11,  9,  5,  3,  8,	 4,  1, 14,  8, 13,  6,  2, 11, 15, 12,  9,  7,  3, 10,  5,  0,	15, 12,  8,  2,  4,  9,  1,  7,  5, 11,  3, 14, 10,  0,  6, 13,	/* S2 */	15,  1,  8, 14,  6, 11,  3,  4,  9,  7,  2, 13, 12,  0,  5, 10,	 3, 13,  4,  7, 15,  2,  8, 14, 12,  0,  1, 10,  6,  9, 11,  5,	 0, 14,  7, 11, 10,  4, 13,  1,  5,  8, 12,  6,  9,  3,  2, 15,	13,  8, 10,  1,  3, 15,  4,  2, 11,  6,  7, 12,  0,  5, 14,  9,	/* S3 */	10,  0,  9, 14,  6,  3, 15,  5,  1, 13, 12,  7, 11,  4,  2,  8,	13,  7,  0,  9,  3,  4,  6, 10,  2,  8,  5, 14, 12, 11, 15,  1,	13,  6,  4,  9,  8, 15,  3,  0, 11,  1,  2, 12,  5, 10, 14,  7,	 1, 10, 13,  0,  6,  9,  8,  7,  4, 15, 14,  3, 11,  5,  2, 12,	/* S4 */	 7, 13, 14,  3,  0,  6,  9, 10,  1,  2,  8,  5, 11, 12,  4, 15,	13,  8, 11,  5,  6, 15,  0,  3,  4,  7,  2, 12,  1, 10, 14,  9,	10,  6,  9,  0, 12, 11,  7, 13, 15,  1,  3, 14,  5,  2,  8,  4,	 3, 15,  0,  6, 10,  1, 13,  8,  9,  4,  5, 11, 12,  7,  2, 14,	/* S5 */	 2, 12,  4,  1,  7, 10, 11,  6,  8,  5,  3, 15, 13,  0, 14,  9,	14, 11,  2, 12,  4,  7, 13,  1,  5,  0, 15, 10,  3,  9,  8,  6,	 4,  2,  1, 11, 10, 13,  7,  8, 15,  9, 12,  5,  6,  3,  0, 14,	11,  8, 12,  7,  1, 14,  2, 13,  6, 15,  0,  9, 10,  4,  5,  3,	/* S6 */	12,  1, 10, 15,  9,  2,  6,  8,  0, 13,  3,  4, 14,  7,  5, 11,	10, 15,  4,  2,  7, 12,  9,  5,  6,  1, 13, 14,  0, 11,  3,  8,	 9, 14, 15,  5,  2,  8, 12,  3,  7,  0,  4, 10,  1, 13, 11,  6,	 4,  3,  2, 12,  9,  5, 15, 10, 11, 14,  1,  7,  6,  0,  8, 13,	/* S7 */	 4, 11,  2, 14, 15,  0,  8, 13,  3, 12,  9,  7,  5, 10,  6,  1,	13,  0, 11,  7,  4,  9,  1, 10, 14,  3,  5, 12,  2, 15,  8,  6,	 1,  4, 11, 13, 12,  3,  7, 14, 10, 15,  6,  8,  0,  5,  9,  2,	 6, 11, 13,  8,  1,  4, 10,  7,  9,  5,  0, 15, 14,  2,  3, 12,	/* S8 */	13,  2,  8,  4,  6, 15, 11,  1, 10,  9,  3, 14,  5,  0, 12,  7,	 1, 15, 13,  8, 10,  3,  7,  4, 12,  5,  6, 11,  0, 14,  9,  2,	 7, 11,  4,  1,  9, 12, 14,  2,  0,  6, 10, 13, 15,  3,  5,  8,	 2,  1, 14,  7,  4, 10,  8, 13, 15, 12,  9,  0,  3,  5,  6, 11};/* 32-bit permutation function P used on the output of the S-boxes */static char p32i[] = {		16,  7, 20, 21,	29, 12, 28, 17,	 1, 15, 23, 26,	 5, 18, 31, 10,	 2,  8, 24, 14,	32, 27,  3,  9,	19, 13, 30,  6,	22, 11,  4, 25};/* End of DES-defined tables *//* Lookup tables initialized once only at startup by desinit() */static long (*sp)[64];		/* Combined S and P boxes */static char (*iperm)[16][8];	/* Initial and final permutations */static char (*fperm)[16][8];/* bit 0 is left-most in byte */static int bytebit[] = {	0200,0100,040,020,010,04,02,01};static int nibblebit[] = {	 010,04,02,01};static int desmode;/* Allocate space and initialize DES lookup arrays * mode == 0: standard Data Encryption Algorithm * mode == 1: DEA without initial and final permutations for speed */intdesinit(mode)int mode;{	char *malloc();	if(sp != NULL){		/* Already initialized */		return 0;	}	desmode = mode;		if((sp = (long (*)[64])malloc(sizeof(long) * 8 * 64)) == NULL){		return NULL;	}	spinit();	if(mode == 1)	/* No permutations */		return 0;	iperm = (char (*)[16][8])malloc(sizeof(char) * 16 * 16 * 8);	if(iperm == NULL){		free((char *)sp);		return -1;	}	perminit(iperm,ip);	fperm = (char (*)[16][8])malloc(sizeof(char) * 16 * 16 * 8);	if(fperm == NULL){		free((char *)sp);		free((char *)iperm);		return -1;	}	perminit(fperm,fp);		return 0;}/* Free up storage used by DES */voiddesdone(){	if(sp == NULL)		return;	/* Already done */	free((char *)sp);	if(iperm != NULL)		free((char *)iperm);	if(fperm != NULL)		free((char *)fperm);	sp = NULL;	iperm = NULL;	fperm = NULL;}/* Set key (initialize key schedule array) */intsetkey(kn,key)char (*kn)[8];		/* Key schedule */char *key;		/* 64 bits (will use only 56) */{	char pc1m[56];		/* place to modify pc1 into */	char pcr[56];		/* place to rotate pc1 into */	register int i,j,l;	int m;	if(kn == NULL){		return -1;	}	/* Clear key schedule */	memset((char *)kn,0,16*8);	for (j=0; j<56; j++) {		/* convert pc1 to bits of key */		l=pc1[j]-1;		/* integer bit location	 */		m = l & 07;		/* find bit		 */		pc1m[j]=(key[l>>3] &	/* find which key byte l is in */			bytebit[m])	/* and which bit of that byte */			? 1 : 0;	/* and store 1-bit result */	}	for (i=0; i<16; i++) {		/* key chunk for each iteration */		for (j=0; j<56; j++)	/* rotate pc1 the right amount */			pcr[j] = pc1m[(l=j+totrot[i])<(j<28? 28 : 56) ? l: l-28];			/* rotate left and right halves independently */		for (j=0; j<48; j++){	/* select bits individually */			/* check bit that goes to kn[j] */			if (pcr[pc2[j]-1]){				/* mask it in if it's there */				l= j % 6;				kn[i][j/6] |= bytebit[l] >> 2;			}		}	}	return 0;}/* In-place encryption of 64-bit block */intendes(kn,block)char (*kn)[8];		/* Key schedule */char *block;{	register long left,right;	register char *knp;	long work[2]; 		/* Working data storage */	if(kn == NULL || block == NULL)		return -1;	permute(block,iperm,(char *)work);	/* Initial Permutation */#ifdef	LITTLE_ENDIAN	left = byteswap(work[0]);	right = byteswap(work[1]);#else	left = work[0];	right = work[1];#endif	/* Do the 16 rounds.	 * The rounds are numbered from 0 to 15. On even rounds	 * the right half is fed to f() and the result exclusive-ORs	 * the left half; on odd rounds the reverse is done.	 */	knp = &kn[0][0];	left ^= f(right,knp);	knp += 8;	right ^= f(left,knp);	knp += 8;	left ^= f(right,knp);	knp += 8;	right ^= f(left,knp);	knp += 8;	left ^= f(right,knp);	knp += 8;	right ^= f(left,knp);	knp += 8;	left ^= f(right,knp);	knp += 8;	right ^= f(left,knp);	knp += 8;	left ^= f(right,knp);	knp += 8;	right ^= f(left,knp);	knp += 8;	left ^= f(right,knp);	knp += 8;	right ^= f(left,knp);	knp += 8;	left ^= f(right,knp);	knp += 8;	right ^= f(left,knp);	knp += 8;	left ^= f(right,knp);	knp += 8;	right ^= f(left,knp);	/* Left/right half swap, plus byte swap if little-endian */#ifdef	LITTLE_ENDIAN	work[1] = byteswap(left);	work[0] = byteswap(right);#else	work[0] = right;	work[1] = left;#endif	permute((char *)work,fperm,block);	/* Inverse initial permutation */	return 0;}/* In-place decryption of 64-bit block. This function is the mirror * image of encryption; exactly the same steps are taken, but in * reverse order */intdedes(kn,block)char (*kn)[8];		/* Key schedule */char *block;{	register long left,right;	register char *knp;	long work[2];	/* Working data storage */	if(kn == NULL || block == NULL)		return -1;	permute(block,iperm,(char *)work);	/* Initial permutation */	/* Left/right half swap, plus byte swap if little-endian */#ifdef	LITTLE_ENDIAN	right = byteswap(work[0]);	left = byteswap(work[1]);#else	right = work[0];	left = work[1];#endif	/* Do the 16 rounds in reverse order.	 * The rounds are numbered from 15 to 0. On even rounds	 * the right half is fed to f() and the result exclusive-ORs	 * the left half; on odd rounds the reverse is done.	 */	knp = &kn[15][0];	right ^= f(left,knp);	knp -= 8;	left ^= f(right,knp);	knp -= 8;	right ^= f(left,knp);	knp -= 8;	left ^= f(right,knp);	knp -= 8;	right ^= f(left,knp);	knp -= 8;	left ^= f(right,knp);	knp -= 8;	right ^= f(left,knp);	knp -= 8;	left ^= f(right,knp);	knp -= 8;	right ^= f(left,knp);	knp -= 8;	left ^= f(right,knp);	knp -= 8;	right ^= f(left,knp);	knp -= 8;	left ^= f(right,knp);	knp -= 8;	right ^= f(left,knp);	knp -= 8;	left ^= f(right,knp);	knp -= 8;	right ^= f(left,knp);	knp -= 8;	left ^= f(right,knp);#ifdef	LITTLE_ENDIAN	work[0] = byteswap(left);	work[1] = byteswap(right);#else	work[0] = left;	work[1] = right;#endif	permute((char *)work,fperm,block);	/* Inverse initial permutation */	return 0;}/* Permute inblock with perm */static voidpermute(inblock,perm,outblock)char *inblock, *outblock;		/* result into outblock,64 bits */char perm[16][16][8];			/* 2K bytes defining perm. */{	register char *ib, *ob;		/* ptr to input or output block */	register char *p, *q;	register int j;	if(perm == NULL){		/* No permutation, just copy */		memcpy(outblock,inblock,8);		return;	}	/* Clear output block */	memset(outblock,'\0',8);	ib = inblock;	for (j = 0; j < 16; j += 2, ib++) { /* for each input nibble */		ob = outblock;		p = perm[j][(*ib >> 4) & 0xf];		q = perm[j + 1][*ib & 0xf];		/* and each output byte, OR the masks together */		*ob++ |= *p++ | *q++;		*ob++ |= *p++ | *q++;		*ob++ |= *p++ | *q++;		*ob++ |= *p++ | *q++;		*ob++ |= *p++ | *q++;		*ob++ |= *p++ | *q++;		*ob++ |= *p++ | *q++;		*ob++ |= *p++ | *q++;	}}/* The nonlinear function f(r,k), the heart of DES */static longf(r,subkey)register long r;	/* 32 bits */register char *subkey;	/* 48-bit key for this round */{	register long *spp;	register long rval,rt;	register int er;#ifdef	TRACE	printf("f(%08lx, %02x %02x %02x %02x %02x %02x %02x %02x) = ",		r,		subkey[0], subkey[1], subkey[2],		subkey[3], subkey[4], subkey[5],		subkey[6], subkey[7]);#endif	/* Run E(R) ^ K through the combined S & P boxes.	 * This code takes advantage of a convenient regularity in	 * E, namely that each group of 6 bits in E(R) feeding	 * a single S-box is a contiguous segment of R.	 */	subkey += 7;	/* Compute E(R) for each block of 6 bits, and run thru boxes */	er = ((int)r << 1) | ((r & 0x80000000) ? 1 : 0);	spp = &sp[7][0];	rval = spp[(er ^ *subkey--) & 0x3f];	spp -= 64;	rt = (unsigned long)r >> 3;	rval |= spp[((int)rt ^ *subkey--) & 0x3f];	spp -= 64;	rt >>= 4;	rval |= spp[((int)rt ^ *subkey--) & 0x3f];	spp -= 64;	rt >>= 4;	rval |= spp[((int)rt ^ *subkey--) & 0x3f];	spp -= 64;	rt >>= 4;	rval |= spp[((int)rt ^ *subkey--) & 0x3f];	spp -= 64;	rt >>= 4;	rval |= spp[((int)rt ^ *subkey--) & 0x3f];	spp -= 64;	rt >>= 4;	rval |= spp[((int)rt ^ *subkey--) & 0x3f];	spp -= 64;	rt >>= 4;	rt |= (r & 1) << 5;	rval |= spp[((int)rt ^ *subkey) & 0x3f];#ifdef	TRACE	printf(" %08lx\n",rval);#endif	return rval;}/* initialize a perm array */static voidperminit(perm,p)char perm[16][16][8];			/* 64-bit, either init or final */char p[64];{	register int l, j, k;	int i,m;	/* Clear the permutation array */	memset((char *)perm,0,16*16*8);	for (i=0; i<16; i++)		/* each input nibble position */		for (j = 0; j < 16; j++)/* each possible input nibble */		for (k = 0; k < 64; k++)/* each output bit position */		{   l = p[k] - 1;	/* where does this bit come from*/			if ((l >> 2) != i)  /* does it come from input posn?*/			continue;	/* if not, bit k is 0	 */			if (!(j & nibblebit[l & 3]))			continue;	/* any such bit in input? */			m = k & 07;	/* which bit is this in the byte*/			perm[i][j][k>>3] |= bytebit[m];		}}/* Initialize the lookup table for the combined S and P boxes */static voidspinit(){	char pbox[32];	int p,i,s,j,rowcol;	long val;	/* Compute pbox, the inverse of p32i.	 * This is easier to work with	 */	for(p=0;p<32;p++){		for(i=0;i<32;i++){			if(p32i[i]-1 == p){				pbox[p] = i;				break;			}		}	}	for(s = 0; s < 8; s++){			/* For each S-box */		for(i=0; i<64; i++){		/* For each possible input */			val = 0;			/* The row number is formed from the first and last			 * bits; the column number is from the middle 4			 */			rowcol = (i & 32) | ((i & 1) ? 16 : 0) | ((i >> 1) & 0xf);			for(j=0;j<4;j++){	/* For each output bit */				if(si[s][rowcol] & (8 >> j)){				 val |= 1L << (31 - pbox[4*s + j]);				}			}			sp[s][i] = val;#ifdef	DEBUG			printf("sp[%d][%2d] = %08lx\n",s,i,sp[s][i]);#endif		}	}}#ifdef	LITTLE_ENDIAN/* Byte swap a long */static longbyteswap(x)unsigned long x;{	register char *cp,tmp;	cp = (char *)&x;	tmp = cp[3];	cp[3] = cp[0];	cp[0] = tmp;	tmp = cp[2];	cp[2] = cp[1];	cp[1] = tmp;	return x;}#endif