RealVNC_decrypt.c

/*
Instructions:
1) Hardcode the encrypted password
2) Compile and run.
$ gcc -o RealVNC_decrypt RealVNC_decrypt.c && ./RealVNC_decrypt
*/


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>

#define MAXPWLEN 8
#define CHALLENGESIZE 16
#define EN0     0       /* MODE == encrypt */
#define DE1     1       /* MODE == decrypt */

extern int vncEncryptPasswd(char *passwd, char *fname);
extern char *vncDecryptPasswd(char *fname);
extern void vncRandomBytes(unsigned char *bytes);
extern void vncEncryptBytes(unsigned char *bytes, const char *passwd);
extern void deskey(unsigned char *, int);
extern void usekey(unsigned long *);
extern void cpkey(unsigned long *);
extern void des(unsigned char *, unsigned char *);

unsigned char fixedkey[8] = {23,82,107,6,35,78,88,7};

void main (void){

	/* put your password hash here in p[]

	   Example: 
	     67a5448ea85a3dd8d8d1e367e1d17646
	     p[]={0x67,0xa5,0x44,0x8e,0xa8,0x5a,0x3d,0xd8}
	     p1[]={0xd8,0xd1,0xe3,0x67,0xe1,0xd1,0x76,0x46};
	 */

	char p[]={0x67,0xa5,0x44,0x8e,0xa8,0x5a,0x3d,0xd8};
	char p1[]={0xd8,0xd1,0xe3,0x67,0xe1,0xd1,0x76,0x46};

	printf("%8s",vncDecryptPasswd(p));
	printf("%s\n",vncDecryptPasswd(p1));

}



char *
vncDecryptPasswd(char *inouttext)
{
    unsigned char *passwd = (unsigned char *)malloc(9);

    deskey(fixedkey, DE1);
    des(inouttext, passwd);

    passwd[8] = 0;

    return (char *)passwd;
}


static void scrunch(unsigned char *, unsigned long *);
static void unscrun(unsigned long *, unsigned char *);
static void desfunc(unsigned long *, unsigned long *);
static void cookey(unsigned long *);

static unsigned long KnL[32] = { 0L };
static unsigned long KnR[32] = { 0L };
static unsigned long Kn3[32] = { 0L };
static unsigned char Df_Key[24] = {
	0x01,0x23,0x45,0x67,0x89,0xab,0xcd,0xef,
	0xfe,0xdc,0xba,0x98,0x76,0x54,0x32,0x10,
	0x89,0xab,0xcd,0xef,0x01,0x23,0x45,0x67 };

static unsigned short bytebit[8]	= {
	01, 02, 04, 010, 020, 040, 0100, 0200 };

static unsigned long bigbyte[24] = {
	0x800000L,	0x400000L,	0x200000L,	0x100000L,
	0x80000L,	0x40000L,	0x20000L,	0x10000L,
	0x8000L,	0x4000L,	0x2000L,	0x1000L,
	0x800L, 	0x400L, 	0x200L, 	0x100L,
	0x80L,		0x40L,		0x20L,		0x10L,
	0x8L,		0x4L,		0x2L,		0x1L	};

/* Use the key schedule specified in the Standard (ANSI X3.92-1981). */

static unsigned char pc1[56] = {
	56, 48, 40, 32, 24, 16,  8,	 0, 57, 49, 41, 33, 25, 17,
	 9,  1, 58, 50, 42, 34, 26,	18, 10,  2, 59, 51, 43, 35,
	62, 54, 46, 38, 30, 22, 14,	 6, 61, 53, 45, 37, 29, 21,
	13,  5, 60, 52, 44, 36, 28,	20, 12,  4, 27, 19, 11,  3 };

static unsigned char totrot[16] = {
	1,2,4,6,8,10,12,14,15,17,19,21,23,25,27,28 };

static unsigned char pc2[48] = {
	13, 16, 10, 23,  0,  4,  2, 27, 14,  5, 20,  9,
	22, 18, 11,  3, 25,  7, 15,  6, 26, 19, 12,  1,
	40, 51, 30, 36, 46, 54, 29, 39, 50, 44, 32, 47,
	43, 48, 38, 55, 33, 52, 45, 41, 49, 35, 28, 31 };

void deskey(key, edf)	/* Thanks to James Gillogly & Phil Karn! */
unsigned char *key;
int edf;
{
	register int i, j, l, m, n;
	unsigned char pc1m[56], pcr[56];
	unsigned long kn[32];

	for ( j = 0; j < 56; j++ ) {
		l = pc1[j];
		m = l & 07;
		pc1m[j] = (key[l >> 3] & bytebit[m]) ? 1 : 0;
		}
	for( i = 0; i < 16; i++ ) {
		if( edf == DE1 ) m = (15 - i) << 1;
		else m = i << 1;
		n = m + 1;
		kn[m] = kn[n] = 0L;
		for( j = 0; j < 28; j++ ) {
			l = j + totrot[i];
			if( l < 28 ) pcr[j] = pc1m[l];
			else pcr[j] = pc1m[l - 28];
			}
		for( j = 28; j < 56; j++ ) {
		    l = j + totrot[i];
		    if( l < 56 ) pcr[j] = pc1m[l];
		    else pcr[j] = pc1m[l - 28];
		    }
		for( j = 0; j < 24; j++ ) {
			if( pcr[pc2[j]] ) kn[m] |= bigbyte[j];
			if( pcr[pc2[j+24]] ) kn[n] |= bigbyte[j];
			}
		}
	cookey(kn);
	return;
	}

static void cookey(raw1)
register unsigned long *raw1;
{
	register unsigned long *cook, *raw0;
	unsigned long dough[32];
	register int i;

	cook = dough;
	for( i = 0; i < 16; i++, raw1++ ) {
		raw0 = raw1++;
		*cook	 = (*raw0 & 0x00fc0000L) << 6;
		*cook	|= (*raw0 & 0x00000fc0L) << 10;
		*cook	|= (*raw1 & 0x00fc0000L) >> 10;
		*cook++ |= (*raw1 & 0x00000fc0L) >> 6;
		*cook	 = (*raw0 & 0x0003f000L) << 12;
		*cook	|= (*raw0 & 0x0000003fL) << 16;
		*cook	|= (*raw1 & 0x0003f000L) >> 4;
		*cook++ |= (*raw1 & 0x0000003fL);
		}
	usekey(dough);
	return;
	}

void cpkey(into)
register unsigned long *into;
{
	register unsigned long *from, *endp;

	from = KnL, endp = &KnL[32];
	while( from < endp ) *into++ = *from++;
	return;
	}

void usekey(from)
register unsigned long *from;
{
	register unsigned long *to, *endp;

	to = KnL, endp = &KnL[32];
	while( to < endp ) *to++ = *from++;
	return;
	}

void des(inblock, outblock)
unsigned char *inblock, *outblock;
{
	unsigned long work[2];

	scrunch(inblock, work);
	desfunc(work, KnL);
	unscrun(work, outblock);
	return;
	}

static void scrunch(outof, into)
register unsigned char *outof;
register unsigned long *into;
{
	*into	 = (*outof++ & 0xffL) << 24;
	*into	|= (*outof++ & 0xffL) << 16;
	*into	|= (*outof++ & 0xffL) << 8;
	*into++ |= (*outof++ & 0xffL);
	*into	 = (*outof++ & 0xffL) << 24;
	*into	|= (*outof++ & 0xffL) << 16;
	*into	|= (*outof++ & 0xffL) << 8;
	*into	|= (*outof   & 0xffL);
	return;
	}

static void unscrun(outof, into)
register unsigned long *outof;
register unsigned char *into;
{
	*into++ = (*outof >> 24) & 0xffL;
	*into++ = (*outof >> 16) & 0xffL;
	*into++ = (*outof >>  8) & 0xffL;
	*into++ =  *outof++	 & 0xffL;
	*into++ = (*outof >> 24) & 0xffL;
	*into++ = (*outof >> 16) & 0xffL;
	*into++ = (*outof >>  8) & 0xffL;
	*into	=  *outof	 & 0xffL;
	return;
	}

static unsigned long SP1[64] = {
	0x01010400L, 0x00000000L, 0x00010000L, 0x01010404L,
	0x01010004L, 0x00010404L, 0x00000004L, 0x00010000L,
	0x00000400L, 0x01010400L, 0x01010404L, 0x00000400L,
	0x01000404L, 0x01010004L, 0x01000000L, 0x00000004L,
	0x00000404L, 0x01000400L, 0x01000400L, 0x00010400L,
	0x00010400L, 0x01010000L, 0x01010000L, 0x01000404L,
	0x00010004L, 0x01000004L, 0x01000004L, 0x00010004L,
	0x00000000L, 0x00000404L, 0x00010404L, 0x01000000L,
	0x00010000L, 0x01010404L, 0x00000004L, 0x01010000L,
	0x01010400L, 0x01000000L, 0x01000000L, 0x00000400L,
	0x01010004L, 0x00010000L, 0x00010400L, 0x01000004L,
	0x00000400L, 0x00000004L, 0x01000404L, 0x00010404L,
	0x01010404L, 0x00010004L, 0x01010000L, 0x01000404L,
	0x01000004L, 0x00000404L, 0x00010404L, 0x01010400L,
	0x00000404L, 0x01000400L, 0x01000400L, 0x00000000L,
	0x00010004L, 0x00010400L, 0x00000000L, 0x01010004L };

static unsigned long SP2[64] = {
	0x80108020L, 0x80008000L, 0x00008000L, 0x00108020L,
	0x00100000L, 0x00000020L, 0x80100020L, 0x80008020L,
	0x80000020L, 0x80108020L, 0x80108000L, 0x80000000L,
	0x80008000L, 0x00100000L, 0x00000020L, 0x80100020L,
	0x00108000L, 0x00100020L, 0x80008020L, 0x00000000L,
	0x80000000L, 0x00008000L, 0x00108020L, 0x80100000L,
	0x00100020L, 0x80000020L, 0x00000000L, 0x00108000L,
	0x00008020L, 0x80108000L, 0x80100000L, 0x00008020L,
	0x00000000L, 0x00108020L, 0x80100020L, 0x00100000L,
	0x80008020L, 0x80100000L, 0x80108000L, 0x00008000L,
	0x80100000L, 0x80008000L, 0x00000020L, 0x80108020L,
	0x00108020L, 0x00000020L, 0x00008000L, 0x80000000L,
	0x00008020L, 0x80108000L, 0x00100000L, 0x80000020L,
	0x00100020L, 0x80008020L, 0x80000020L, 0x00100020L,
	0x00108000L, 0x00000000L, 0x80008000L, 0x00008020L,
	0x80000000L, 0x80100020L, 0x80108020L, 0x00108000L };

static unsigned long SP3[64] = {
	0x00000208L, 0x08020200L, 0x00000000L, 0x08020008L,
	0x08000200L, 0x00000000L, 0x00020208L, 0x08000200L,
	0x00020008L, 0x08000008L, 0x08000008L, 0x00020000L,
	0x08020208L, 0x00020008L, 0x08020000L, 0x00000208L,
	0x08000000L, 0x00000008L, 0x08020200L, 0x00000200L,
	0x00020200L, 0x08020000L, 0x08020008L, 0x00020208L,
	0x08000208L, 0x00020200L, 0x00020000L, 0x08000208L,
	0x00000008L, 0x08020208L, 0x00000200L, 0x08000000L,
	0x08020200L, 0x08000000L, 0x00020008L, 0x00000208L,
	0x00020000L, 0x08020200L, 0x08000200L, 0x00000000L,
	0x00000200L, 0x00020008L, 0x08020208L, 0x08000200L,
	0x08000008L, 0x00000200L, 0x00000000L, 0x08020008L,
	0x08000208L, 0x00020000L, 0x08000000L, 0x08020208L,
	0x00000008L, 0x00020208L, 0x00020200L, 0x08000008L,
	0x08020000L, 0x08000208L, 0x00000208L, 0x08020000L,
	0x00020208L, 0x00000008L, 0x08020008L, 0x00020200L };

static unsigned long SP4[64] = {
	0x00802001L, 0x00002081L, 0x00002081L, 0x00000080L,
	0x00802080L, 0x00800081L, 0x00800001L, 0x00002001L,
	0x00000000L, 0x00802000L, 0x00802000L, 0x00802081L,
	0x00000081L, 0x00000000L, 0x00800080L, 0x00800001L,
	0x00000001L, 0x00002000L, 0x00800000L, 0x00802001L,
	0x00000080L, 0x00800000L, 0x00002001L, 0x00002080L,
	0x00800081L, 0x00000001L, 0x00002080L, 0x00800080L,
	0x00002000L, 0x00802080L, 0x00802081L, 0x00000081L,
	0x00800080L, 0x00800001L, 0x00802000L, 0x00802081L,
	0x00000081L, 0x00000000L, 0x00000000L, 0x00802000L,
	0x00002080L, 0x00800080L, 0x00800081L, 0x00000001L,
	0x00802001L, 0x00002081L, 0x00002081L, 0x00000080L,
	0x00802081L, 0x00000081L, 0x00000001L, 0x00002000L,
	0x00800001L, 0x00002001L, 0x00802080L, 0x00800081L,
	0x00002001L, 0x00002080L, 0x00800000L, 0x00802001L,
	0x00000080L, 0x00800000L, 0x00002000L, 0x00802080L };

static unsigned long SP5[64] = {
	0x00000100L, 0x02080100L, 0x02080000L, 0x42000100L,
	0x00080000L, 0x00000100L, 0x40000000L, 0x02080000L,
	0x40080100L, 0x00080000L, 0x02000100L, 0x40080100L,
	0x42000100L, 0x42080000L, 0x00080100L, 0x40000000L,
	0x02000000L, 0x40080000L, 0x40080000L, 0x00000000L,
	0x40000100L, 0x42080100L, 0x42080100L, 0x02000100L,
	0x42080000L, 0x40000100L, 0x00000000L, 0x42000000L,
	0x02080100L, 0x02000000L, 0x42000000L, 0x00080100L,
	0x00080000L, 0x42000100L, 0x00000100L, 0x02000000L,
	0x40000000L, 0x02080000L, 0x42000100L, 0x40080100L,
	0x02000100L, 0x40000000L, 0x42080000L, 0x02080100L,
	0x40080100L, 0x00000100L, 0x02000000L, 0x42080000L,
	0x42080100L, 0x00080100L, 0x42000000L, 0x42080100L,
	0x02080000L, 0x00000000L, 0x40080000L, 0x42000000L,
	0x00080100L, 0x02000100L, 0x40000100L, 0x00080000L,
	0x00000000L, 0x40080000L, 0x02080100L, 0x40000100L };

static unsigned long SP6[64] = {
	0x20000010L, 0x20400000L, 0x00004000L, 0x20404010L,
	0x20400000L, 0x00000010L, 0x20404010L, 0x00400000L,
	0x20004000L, 0x00404010L, 0x00400000L, 0x20000010L,
	0x00400010L, 0x20004000L, 0x20000000L, 0x00004010L,
	0x00000000L, 0x00400010L, 0x20004010L, 0x00004000L,
	0x00404000L, 0x20004010L, 0x00000010L, 0x20400010L,
	0x20400010L, 0x00000000L, 0x00404010L, 0x20404000L,
	0x00004010L, 0x00404000L, 0x20404000L, 0x20000000L,
	0x20004000L, 0x00000010L, 0x20400010L, 0x00404000L,
	0x20404010L, 0x00400000L, 0x00004010L, 0x20000010L,
	0x00400000L, 0x20004000L, 0x20000000L, 0x00004010L,
	0x20000010L, 0x20404010L, 0x00404000L, 0x20400000L,
	0x00404010L, 0x20404000L, 0x00000000L, 0x20400010L,
	0x00000010L, 0x00004000L, 0x20400000L, 0x00404010L,
	0x00004000L, 0x00400010L, 0x20004010L, 0x00000000L,
	0x20404000L, 0x20000000L, 0x00400010L, 0x20004010L };

static unsigned long SP7[64] = {
	0x00200000L, 0x04200002L, 0x04000802L, 0x00000000L,
	0x00000800L, 0x04000802L, 0x00200802L, 0x04200800L,
	0x04200802L, 0x00200000L, 0x00000000L, 0x04000002L,
	0x00000002L, 0x04000000L, 0x04200002L, 0x00000802L,
	0x04000800L, 0x00200802L, 0x00200002L, 0x04000800L,
	0x04000002L, 0x04200000L, 0x04200800L, 0x00200002L,
	0x04200000L, 0x00000800L, 0x00000802L, 0x04200802L,
	0x00200800L, 0x00000002L, 0x04000000L, 0x00200800L,
	0x04000000L, 0x00200800L, 0x00200000L, 0x04000802L,
	0x04000802L, 0x04200002L, 0x04200002L, 0x00000002L,
	0x00200002L, 0x04000000L, 0x04000800L, 0x00200000L,
	0x04200800L, 0x00000802L, 0x00200802L, 0x04200800L,
	0x00000802L, 0x04000002L, 0x04200802L, 0x04200000L,
	0x00200800L, 0x00000000L, 0x00000002L, 0x04200802L,
	0x00000000L, 0x00200802L, 0x04200000L, 0x00000800L,
	0x04000002L, 0x04000800L, 0x00000800L, 0x00200002L };

static unsigned long SP8[64] = {
	0x10001040L, 0x00001000L, 0x00040000L, 0x10041040L,
	0x10000000L, 0x10001040L, 0x00000040L, 0x10000000L,
	0x00040040L, 0x10040000L, 0x10041040L, 0x00041000L,
	0x10041000L, 0x00041040L, 0x00001000L, 0x00000040L,
	0x10040000L, 0x10000040L, 0x10001000L, 0x00001040L,
	0x00041000L, 0x00040040L, 0x10040040L, 0x10041000L,
	0x00001040L, 0x00000000L, 0x00000000L, 0x10040040L,
	0x10000040L, 0x10001000L, 0x00041040L, 0x00040000L,
	0x00041040L, 0x00040000L, 0x10041000L, 0x00001000L,
	0x00000040L, 0x10040040L, 0x00001000L, 0x00041040L,
	0x10001000L, 0x00000040L, 0x10000040L, 0x10040000L,
	0x10040040L, 0x10000000L, 0x00040000L, 0x10001040L,
	0x00000000L, 0x10041040L, 0x00040040L, 0x10000040L,
	0x10040000L, 0x10001000L, 0x10001040L, 0x00000000L,
	0x10041040L, 0x00041000L, 0x00041000L, 0x00001040L,
	0x00001040L, 0x00040040L, 0x10000000L, 0x10041000L };

static void desfunc(block, keys)
register unsigned long *block, *keys;
{
	register unsigned long fval, work, right, leftt;
	register int round;

	leftt = block[0];
	right = block[1];
	work = ((leftt >> 4) ^ right) & 0x0f0f0f0fL;
	right ^= work;
	leftt ^= (work << 4);
	work = ((leftt >> 16) ^ right) & 0x0000ffffL;
	right ^= work;
	leftt ^= (work << 16);
	work = ((right >> 2) ^ leftt) & 0x33333333L;
	leftt ^= work;
	right ^= (work << 2);
	work = ((right >> 8) ^ leftt) & 0x00ff00ffL;
	leftt ^= work;
	right ^= (work << 8);
	right = ((right << 1) | ((right >> 31) & 1L)) & 0xffffffffL;
	work = (leftt ^ right) & 0xaaaaaaaaL;
	leftt ^= work;
	right ^= work;
	leftt = ((leftt << 1) | ((leftt >> 31) & 1L)) & 0xffffffffL;

	for( round = 0; round < 8; round++ ) {
		work  = (right << 28) | (right >> 4);
		work ^= *keys++;
		fval  = SP7[ work		 & 0x3fL];
		fval |= SP5[(work >>  8) & 0x3fL];
		fval |= SP3[(work >> 16) & 0x3fL];
		fval |= SP1[(work >> 24) & 0x3fL];
		work  = right ^ *keys++;
		fval |= SP8[ work		 & 0x3fL];
		fval |= SP6[(work >>  8) & 0x3fL];
		fval |= SP4[(work >> 16) & 0x3fL];
		fval |= SP2[(work >> 24) & 0x3fL];
		leftt ^= fval;
		work  = (leftt << 28) | (leftt >> 4);
		work ^= *keys++;
		fval  = SP7[ work		 & 0x3fL];
		fval |= SP5[(work >>  8) & 0x3fL];
		fval |= SP3[(work >> 16) & 0x3fL];
		fval |= SP1[(work >> 24) & 0x3fL];
		work  = leftt ^ *keys++;
		fval |= SP8[ work		 & 0x3fL];
		fval |= SP6[(work >>  8) & 0x3fL];
		fval |= SP4[(work >> 16) & 0x3fL];
		fval |= SP2[(work >> 24) & 0x3fL];
		right ^= fval;
		}

	right = (right << 31) | (right >> 1);
	work = (leftt ^ right) & 0xaaaaaaaaL;
	leftt ^= work;
	right ^= work;
	leftt = (leftt << 31) | (leftt >> 1);
	work = ((leftt >> 8) ^ right) & 0x00ff00ffL;
	right ^= work;
	leftt ^= (work << 8);
	work = ((leftt >> 2) ^ right) & 0x33333333L;
	right ^= work;
	leftt ^= (work << 2);
	work = ((right >> 16) ^ leftt) & 0x0000ffffL;
	leftt ^= work;
	right ^= (work << 16);
	work = ((right >> 4) ^ leftt) & 0x0f0f0f0fL;
	leftt ^= work;
	right ^= (work << 4);
	*block++ = right;
	*block = leftt;
	return;
	}