#include "stdafx.h"
#include "evaqqcrypt.h"
#include <Winsock2.h>

EvaQQCrypt::EvaQQCrypt(void)
{
}

EvaQQCrypt::~EvaQQCrypt(void)
{
}

void EvaQQCrypt::Tea_Encipher(unsigned long *const v, const unsigned long *const k, unsigned long *const w)
{
	register unsigned long 		y     = ntohl(v[0]),		z     = ntohl(v[1]),		a     = ntohl(k[0]),		b     = ntohl(k[1]),		c     = ntohl(k[2]),		d     = ntohl(k[3]),		n     = 0x10,       /* do encrypt 16 (0x10) times */		sum   = 0,		delta = 0x9E3779B9; /*  0x9E3779B9 - 0x100000000 = -0x61C88647 */	while (n-- > 0) {		sum += delta;		y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);		z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);	}	w[0] = htonl(y); w[1] = htonl(z);
}
void EvaQQCrypt::Tea_Decipher(unsigned long *const v, const unsigned long *const k, unsigned long *const w)
{
	register unsigned long		y     = ntohl(v[0]),		z     = ntohl(v[1]),		a     = ntohl(k[0]),		b     = ntohl(k[1]),		c     = ntohl(k[2]),		d     = ntohl(k[3]),		n     = 0x10,		sum   = 0xE3779B90, 		/* why this ? must be related with n value*/		delta = 0x9E3779B9;	/* sum = delta<<5, in general sum = delta * n */	while (n-- > 0) {		z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);		y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);		sum -= delta;	}	w[0] = htonl(y); w[1] = htonl(z);
}

void EvaQQCrypt::Encrypt (  						  unsigned char*  instr,						  int             instrlen,						  unsigned char*  key,						  unsigned char*  outstr,						  int*            outstrlen_prt)
{
	unsigned char 		plain[8],         /* plain text buffer*/		plain_pre_8[8],   /* plain text buffer, previous 8 bytes*/		* crypted,        /* crypted text*/		* crypted_pre_8,  /* crypted test, previous 8 bytes*/		* inp;            /* current position in instr*/	int 		pos_in_byte = 1,  /* loop in the byte */		is_header=1,      /* header is one byte*/		count=0,          /* number of bytes being crypted*/		padding = 0;      /* number of padding stuff*/	//void encrypt_every_8_byte (void);    	/*** we encrypt every eight byte ***/#define encrypt_every_8_byte()  \	{\	for(pos_in_byte=0; pos_in_byte<8; pos_in_byte++) {\	if(is_header) { plain[pos_in_byte] ^= plain_pre_8[pos_in_byte]; }\			else { plain[pos_in_byte] ^= crypted_pre_8[pos_in_byte]; }\	} /* prepare plain text*/\	Tea_Encipher( (unsigned long *) plain,\	(unsigned long *) key, \	(unsigned long *) crypted);   /* encrypt it*/\	\	for(pos_in_byte=0; pos_in_byte<8; pos_in_byte++) {\	crypted[pos_in_byte] ^= plain_pre_8[pos_in_byte]; \	} \	memcpy(plain_pre_8, plain, 8);     /* prepare next*/\	\	crypted_pre_8   =   crypted;       /* store position of previous 8 byte*/\	crypted         +=  8;             /* prepare next output*/\	count           +=  8;             /* outstrlen increase by 8*/\	pos_in_byte     =   0;             /* back to start*/\	is_header       =   0;             /* and exit header*/\	}/* encrypt_every_8_byte*/	pos_in_byte = (instrlen + 0x0a) % 8; /* header padding decided by instrlen*/	if (pos_in_byte) { 		pos_in_byte = 8 - pos_in_byte; 	}	plain[0] = (rand() & 0xf8) | pos_in_byte;	memset(plain+1, rand()&0xff, pos_in_byte++);	memset(plain_pre_8, 0x00, sizeof(plain_pre_8));	crypted = crypted_pre_8 = outstr;	padding = 1; /* pad some stuff in header*/	while (padding <= 2) { /* at most two byte */		if(pos_in_byte < 8) { plain[pos_in_byte++] = rand() & 0xff; padding ++; } 		if(pos_in_byte == 8){ encrypt_every_8_byte(); } 	}	inp = instr;	while (instrlen > 0) {		if (pos_in_byte < 8) { plain[pos_in_byte++] = *(inp++); instrlen --; }		if (pos_in_byte == 8){ encrypt_every_8_byte(); }	}	padding = 1; /* pad some stuff in tailer*/	while (padding <= 7) { /* at most sever byte*/		if (pos_in_byte < 8) { plain[pos_in_byte++] = 0x00; padding ++; }		if (pos_in_byte == 8){ encrypt_every_8_byte(); }	} 	*outstrlen_prt = count;

}

int EvaQQCrypt::rand(void)
{
	/* it can be the real random seed function*/	return 0xdead; /* override with number, convenient for debug*/	
}

int EvaQQCrypt::Decrypt (						 unsigned char*  instr,						 int             instrlen,						 unsigned char*  key,						 unsigned char*  outstr,						 int*            outstrlen_ptr){	unsigned char 		decrypted[8], m[8],		* crypt_buff, 		* crypt_buff_pre_8, 		* outp;	int 		count, 		context_start, 		pos_in_byte, 		padding;#define decrypt_every_8_byte()  {\	bool bNeedRet = false;\	for (pos_in_byte = 0; pos_in_byte < 8; pos_in_byte ++ ) {\	if (context_start + pos_in_byte >= instrlen) \	{\	bNeedRet = true;\	break;\	}\	decrypted[pos_in_byte] ^= crypt_buff[pos_in_byte];\	}\	if( !bNeedRet ) { \	Tea_Decipher( (unsigned long *) decrypted, \	(unsigned long *) key, \	(unsigned long *) decrypted);\	\	context_start +=  8;\	crypt_buff    +=  8;\	pos_in_byte   =   0;\	}\}/* decrypt_every_8_byte*/	/* at least 16 bytes and %8 == 0*/	if ((instrlen % 8) || (instrlen < 16)) return 0; 	/* get information from header*/	Tea_Decipher( (unsigned long *) instr, 		(unsigned long *) key, 		(unsigned long *) decrypted);	pos_in_byte = decrypted[0] & 0x7;	count = instrlen - pos_in_byte - 10; /* this is the plaintext length*/	/* return if outstr buffer is not large enought or error plaintext length*/	if (*outstrlen_ptr < count || count < 0) return 0;	memset(m, 0, 8);	crypt_buff_pre_8 = m;	*outstrlen_ptr = count;   /* everything is ok! set return string length*/	crypt_buff = instr + 8;   /* address of real data start */	context_start = 8;        /* context is at the second 8 byte*/	pos_in_byte ++;           /* start of paddng stuffv*/	padding = 1;              /* at least one in header*/	while (padding <= 2) {    /* there are 2 byte padding stuff in header*/		if (pos_in_byte < 8) {  /* bypass the padding stuff, none sense data*/			pos_in_byte ++; padding ++;		}		if (pos_in_byte == 8) {			crypt_buff_pre_8 = instr;			//if (! decrypt_every_8_byte()) return 0; 			decrypt_every_8_byte();		}	}/* while*/	outp = outstr;	while(count !=0) {		if (pos_in_byte < 8) {			*outp = crypt_buff_pre_8[pos_in_byte] ^ decrypted[pos_in_byte];			outp ++;			count --;			pos_in_byte ++;		}		if (pos_in_byte == 8) {			crypt_buff_pre_8 = crypt_buff - 8;			//if (! decrypt_every_8_byte()) return 0;			decrypt_every_8_byte();		}	}/* while*/	for (padding = 1; padding < 8; padding ++) {		if (pos_in_byte < 8) {			if (crypt_buff_pre_8[pos_in_byte] ^ decrypted[pos_in_byte]) return 0;			pos_in_byte ++; 		}		if (pos_in_byte == 8 ) {			crypt_buff_pre_8 = crypt_buff;			//if (! decrypt_every_8_byte()) return 0; 			decrypt_every_8_byte();		}	}/* for*/	return 1;}
int EvaQQCrypt::qq_crypt (						  unsigned char   flag,						  unsigned char*  instr,						  int             instrlen,						  unsigned char*  key,						  unsigned char*  outstr,						  int*            outstrlen_ptr){	if (flag == DECRYPT)		return EvaQQCrypt::Decrypt(instr, instrlen, key, outstr, outstrlen_ptr);	else 		if (flag == ENCRYPT)			EvaQQCrypt::Encrypt(instr, instrlen, key, outstr, outstrlen_ptr);	return 1; /* flag must be DECRYPT or ENCRYPT*/}/* qq_crypt*/