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#include "chatCrypt.h"
#define swap_byte(x,y) t = *(x); *(x) = *(y); *(y) = t
void gs_prepare_key(const unsigned char *key_data_ptr, int key_data_len, gs_crypt_key *key)
{
unsigned char t;
unsigned char index1;
unsigned char index2;
unsigned char* state;
int counter;
state = &key->state[0];
for(counter = 0; counter < 256; counter++)
state[255 - counter] = (unsigned char)counter; //crt - we fill reverse of normal
key->x = 0;
key->y = 0;
index1 = 0;
index2 = 0;
for(counter = 0; counter < 256; counter++)
{
index2 = (unsigned char)((key_data_ptr[index1] + state[counter] + index2) % 256);
swap_byte(&state[counter], &state[index2]);
index1 = (unsigned char)((index1 + 1) % key_data_len);
}
}
void gs_crypt(unsigned char *buffer_ptr, int buffer_len, gs_crypt_key *key)
{
unsigned char t;
unsigned char x;
unsigned char y;
unsigned char* state;
unsigned char xorIndex;
int counter;
x = key->x;
y = key->y;
state = &key->state[0];
for(counter = 0; counter < buffer_len; counter++)
{
x = (unsigned char)((x + 1) % 256);
y = (unsigned char)((state[x] + y) % 256);
swap_byte(&state[x], &state[y]);
xorIndex = (unsigned char)((state[x] + state[y]) % 256);
buffer_ptr[counter] ^= state[xorIndex];
}
key->x = x;
key->y = y;
}
void gs_xcode_buf(char *buf, int len, char *enckey)
{
int i;
char *pos = enckey;
for (i = 0 ; i < len ; i++)
{
buf[i] ^= *pos++;
if (*pos == 0)
pos = enckey;
}
}
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