/* * This program implements the * Proposed Federal Information Processing *  Data Encryption Standard. * See Federal Register, March 17, 1975 (40FR12134) *//* * Initial permutation, */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, FP = 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,};/* * Permuted-choice 1 from the key bits * to yield C and D. * Note that bits 8,16... are left out: * They are intended for a parity check. */static	char	PC1_C[] = {	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,};static	char	PC1_D[] {	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,};/* * Sequence of shifts used for the key schedule.*/static	char	shifts[] = {	1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1,};/* * Permuted-choice 2, to pick out the bits from * the CD array that generate the key schedule. */static	char	PC2_C[] = {	14,17,11,24, 1, 5,	 3,28,15, 6,21,10,	23,19,12, 4,26, 8,	16, 7,27,20,13, 2,};static	char	PC2_D[] = {	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 C and D arrays used to calculate the key schedule. */static	char	C[28];static	char	D[28];/* * The key schedule. * Generated from the key. */static	char	KS[16][48];/* * Set up the key schedule from the key. */setkey(key)char *key;{	register i, j, k;	int t;	/*	 * First, generate C and D by permuting	 * the key.  The low order bit of each	 * 8-bit char is not used, so C and D are only 28	 * bits apiece.	 */	for (i=0; i<28; i++) {		C[i] = key[PC1_C[i]-1];		D[i] = key[PC1_D[i]-1];	}	/*	 * To generate Ki, rotate C and D according	 * to schedule and pick up a permutation	 * using PC2.	 */	for (i=0; i<16; i++) {		/*		 * rotate.		 */		for (k=0; k<shifts[i]; k++) {			t = C[0];			for (j=0; j<28-1; j++)				C[j] = C[j+1];			C[27] = t;			t = D[0];			for (j=0; j<28-1; j++)				D[j] = D[j+1];			D[27] = t;		}		/*		 * get Ki. Note C and D are concatenated.		 */		for (j=0; j<24; j++) {			KS[i][j] = C[PC2_C[j]-1];			KS[i][j+24] = D[PC2_D[j]-28-1];		}	}}/* * The E bit-selection table. */static	char	E[48];static	char	e[] {	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,};/* * The 8 selection functions. * For some reason, they give a 0-origin * index, unlike everything else. */static	char	S[8][64] {	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,	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,	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,	 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,	 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,	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,	 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,	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,};/* * P is a permutation on the selected combination * of the current L and key. */static	char	P[] {	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,};/* * The current block, divided into 2 halves. */static	char	L[32], R[32];static	char	tempL[32];static	char	f[32];/* * The combination of the key and the input, before selection. */static	char	preS[48];/* * The payoff: encrypt a block. */encrypt(block, edflag)char *block;{	int i, ii;	register t, j, k;	/*	 * First, permute the bits in the input	 */	for (j=0; j<64; j++)		L[j] = block[IP[j]-1];	/*	 * Perform an encryption operation 16 times.	 */	for (ii=0; ii<16; ii++) {		/*		 * Set direction		 */		if (edflag)			i = 15-ii;		else			i = ii;		/*		 * Save the R array,		 * which will be the new L.		 */		for (j=0; j<32; j++)			tempL[j] = R[j];		/*		 * Expand R to 48 bits using the E selector;		 * exclusive-or with the current key bits.		 */		for (j=0; j<48; j++)			preS[j] = R[E[j]-1] ^ KS[i][j];		/*		 * The pre-select bits are now considered		 * in 8 groups of 6 bits each.		 * The 8 selection functions map these		 * 6-bit quantities into 4-bit quantities		 * and the results permuted		 * to make an f(R, K).		 * The indexing into the selection functions		 * is peculiar; it could be simplified by		 * rewriting the tables.		 */		for (j=0; j<8; j++) {			t = 6*j;			k = S[j][(preS[t+0]<<5)+				(preS[t+1]<<3)+				(preS[t+2]<<2)+				(preS[t+3]<<1)+				(preS[t+4]<<0)+				(preS[t+5]<<4)];			t = 4*j;			f[t+0] = (k>>3)&01;			f[t+1] = (k>>2)&01;			f[t+2] = (k>>1)&01;			f[t+3] = (k>>0)&01;		}		/*		 * The new R is L ^ f(R, K).		 * The f here has to be permuted first, though.		 */		for (j=0; j<32; j++)			R[j] = L[j] ^ f[P[j]-1];		/*		 * Finally, the new L (the original R)		 * is copied back.		 */		for (j=0; j<32; j++)			L[j] = tempL[j];	}	/*	 * The output L and R are reversed.	 */	for (j=0; j<32; j++) {		t = L[j];		L[j] = R[j];		R[j] = t;	}	/*	 * The final output	 * gets the inverse permutation of the very original.	 */	for (j=0; j<64; j++)		block[j] = L[FP[j]-1];}char *crypt(pw,salt)char *pw;char *salt;{	register i, j, c;	int temp;	static char block[66], iobuf[16];	for(i=0; i<66; i++)		block[i] = 0;	for(i=0; (c= *pw) && i<64; pw++){		for(j=0; j<7; j++, i++)			block[i] = (c>>(6-j)) & 01;		i++;	}		setkey(block);		for(i=0; i<66; i++)		block[i] = 0;	for(i=0;i<48;i++)		E[i] = e[i];	for(i=0;i<2;i++){		c = *salt++;		iobuf[i] = c;		if(c>'Z') c -= 6;		if(c>'9') c -= 7;		c -= '.';		for(j=0;j<6;j++){			if((c>>j) & 01){				temp = E[6*i+j];				E[6*i+j] = E[6*i+j+24];				E[6*i+j+24] = temp;				}			}		}		for(i=0; i<25; i++)		encrypt(block,0);		for(i=0; i<11; i++){		c = 0;		for(j=0; j<6; j++){			c <<= 1;			c |= block[6*i+j];			}		c += '.';		if(c>'9') c += 7;		if(c>'Z') c += 6;		iobuf[i+2] = c;	}	iobuf[i+2] = 0;	if(iobuf[1]==0)		iobuf[1] = iobuf[0];	return(iobuf);}