aes.c

/* aes.c */
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <byteswap.h>

void aes_encrypt(const uint64_t *rk, uint64_t *plaintext, uint64_t *ciphertext);
void aes_expand_key(const uint64_t *key, uint64_t *rk);

int main(int argc, char *argv[]) {
	char key_str[17] = {'\0'};
	char in_str[17] = {'\0'};
    uint64_t rk[22] = {0};
    uint64_t out[2] = {0};
    uint64_t in[2] = {0};
	uint64_t key[2] = {0};

	if (argc != 3) {
		printf("Usage: %s <key> <plaintext>\n", argv[0]);
		return 1;
	}
	if (strlen(argv[1]) != 32) {
		printf("The key should be 16-byte long in hexadecimal.\n");
		return 1;
	}
	if (strlen(argv[2]) != 32) {
		printf("The plaintext should be 16-byte long in hexadecimal.\n");
		return 1;
	}
    
	// Copy key
	strncpy(key_str, argv[1], 16);
	key[0] = bswap_64(strtoull(key_str, NULL, 16));
	strncpy(key_str, argv[1] + 16, 16);
	key[1] = bswap_64(strtoull(key_str, NULL, 16));

	// Key schedule
	aes_expand_key(key, rk);

	// Copy plaintext
	strncpy(in_str, argv[2], 16);
	in[0] = bswap_64(strtoull(in_str, NULL, 16));
	strncpy(in_str, argv[2] + 16, 16);
	in[1] = bswap_64(strtoull(in_str, NULL, 16));

	// Encryption
	aes_encrypt(rk, in, out);
    printf("%016lx%016lx\n", bswap_64(out[0]), bswap_64(out[1]));
    return 0;
}