String obsfucation via MMX instructions

main.c

#include <stdio.h>
#include <xmmintrin.h>
#include <stdint.h>

/**
 * Converts a string from a format where bit 7 of 8 characters form the first
 * byte in a uint64_t, bit 6 of 8 characters form the second byte and so on
 * in a simple attempt to obsfucate strings encoded as integers.
 *
 * @param data The string to destripe
 * @param num_elem The number of uint64_t in data
 * @param buffer The buffer where to store the destripted data
 */
void destripe(uint64_t* data, size_t num_elem, char* buffer);
 
/* Compile this program with gcc -Os main.c then strip the binary (or don't) and run
 * strings on it to see on the binary and notice the string "01234567" is nowhere in the binary
 */
int main(int argc, char** argv) {
    //A method of string obsfucation
    uint64_t data[] = { 0x0000FFFF000F3355LL, 0x0000000000000000LL };
    char str[sizeof(data)] = {0};
    destripe(data, sizeof(data)/sizeof(*data), str);
    printf("%s\n", str);
    return 0;
}

void destripe(uint64_t* data, size_t num_elem, char* buffer) {
    char* pbuf = buffer;
    for( size_t i = 0; i < num_elem; ++i ) {
        __m64 cur = _mm_set_pi64x(data[i]);
        for( size_t j = 0; j < 8; ++j ) {
            pbuf[j] = (char)_mm_movemask_pi8(cur);
            cur = _mm_slli_si64(cur, 1);
        }
        pbuf += 8;
    }
}

One neat thing about this method is it only uses MMX instructions that have been around since the mid 90's so virtually every x86 desktop can run it.