blowfish.cpp

各种加密算法的集合

#include "pch.h" 
#include "blowfish.h" 
 
NAMESPACE_BEGIN(CryptoPP) 
 
Blowfish::Blowfish(const byte *key_string, unsigned int keylength, CipherDir dir) 
	: pbox(ROUNDS+2), sbox(4*256) 
{ 
	unsigned i, j=0, k; 
	word32 data, dspace[2] = {0, 0}; 
 
	memcpy(pbox, p_init, sizeof(p_init)); 
	memcpy(sbox, s_init, sizeof(s_init)); 
 
	// Xor key string into encryption key vector 
	for (i=0 ; i<ROUNDS+2 ; ++i) 
	{ 
		data = 0 ; 
		for (k=0 ; k<4 ; ++k ) 
			data = (data << 8) | key_string[j++ % keylength]; 
		pbox[i] ^= data; 
	} 
 
	crypt_block(dspace, pbox); 
 
	for (i=0; i<ROUNDS; i+=2) 
		crypt_block(pbox+i, pbox+i+2); 
 
	crypt_block(pbox+ROUNDS, sbox); 
 
	for (i=0; i<4*256-2; i+=2) 
		crypt_block(sbox+i, sbox+i+2); 
 
	if (dir==DECRYPTION) 
		for (i=0; i<(ROUNDS+2)/2; i++) 
			std::swap(pbox[i], pbox[ROUNDS+1-i]); 
} 
 
// this version is only used to make pbox and sbox 
void Blowfish::crypt_block(const word32 in[2], word32 out[2]) const 
{ 
	word32 left = in[0]; 
	word32 right = in[1]; 
 
	const word32 *const s=sbox; 
	const word32 *p=pbox; 
 
	left ^= p[0]; 
 
	for (unsigned i=0; i<ROUNDS/2; i++) 
	{ 
		right ^= (((s[GETBYTE(left,3)] + s[256+GETBYTE(left,2)]) 
			  ^ s[2*256+GETBYTE(left,1)]) + s[3*256+GETBYTE(left,0)]) 
			  ^ p[2*i+1]; 
 
		left ^= (((s[GETBYTE(right,3)] + s[256+GETBYTE(right,2)]) 
			 ^ s[2*256+GETBYTE(right,1)]) + s[3*256+GETBYTE(right,0)]) 
			 ^ p[2*i+2]; 
	} 
 
	right ^= p[ROUNDS+1]; 
 
	out[0] = right; 
	out[1] = left; 
} 
 
void Blowfish::ProcessBlock(const byte *in, byte *out) const 
{ 
#ifdef IS_LITTLE_ENDIAN 
	word32 left = byteReverse(*(word32 *)in); 
	word32 right = byteReverse(*(word32 *)(in+4)); 
#else 
	word32 left = *(word32 *)in; 
	word32 right = *(word32 *)(in+4); 
#endif 
 
	const word32 *const s=sbox; 
	const word32 *p=pbox; 
 
	left ^= p[0]; 
 
	for (unsigned i=0; i<ROUNDS/2; i++) 
	{ 
		right ^= (((s[GETBYTE(left,3)] + s[256+GETBYTE(left,2)]) 
			  ^ s[2*256+GETBYTE(left,1)]) + s[3*256+GETBYTE(left,0)]) 
			  ^ p[2*i+1]; 
 
		left ^= (((s[GETBYTE(right,3)] + s[256+GETBYTE(right,2)]) 
			 ^ s[2*256+GETBYTE(right,1)]) + s[3*256+GETBYTE(right,0)]) 
			 ^ p[2*i+2]; 
	} 
 
	right ^= p[ROUNDS+1]; 
 
#ifdef IS_LITTLE_ENDIAN 
	*(word32 *)out = byteReverse(right); 
	*(word32 *)(out+4) = byteReverse(left); 
#else 
	*(word32 *)out = right; 
	*(word32 *)(out+4) = left; 
#endif 
} 
 
NAMESPACE_END