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/*
* gcc encrypt_decoy.c -lcrypto
*/
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "openssl/aes.h"
int main() {
AES_KEY enc_key;
unsigned char plain[80] =
"Oh my, there's nothing here... Move along, but don't fall off the "
"edge!\0",
keys[4][16], cipher[4][80];
// Getting 4 random 128 bit keys.
int fd = open("/dev/urandom", O_RDONLY);
if (fd == -1) {
exit(-1);
}
for (int i = 0; i < 4; i++) {
if (read(fd, keys[i], 16) != 16) {
exit(-1);
}
}
close(fd);
// Encrypting the plain text with the 4 keys to 4 cipher texts.
for (int i = 0; i < 4; i++) {
AES_set_encrypt_key(keys[i], 128, &enc_key);
for (int j = 0; j < 5; j++) {
AES_encrypt(plain + 16 * j, cipher[i] + 16 * j, &enc_key);
}
}
// PP the key for copy & paste to the challenge source.
for (int i = 0; i < 4; i++) {
if (i == 0) {
printf("static unsigned char decoy_keys[4][16] = {{");
} else {
printf(" {");
}
for (int j = 0; j < 16; j++) {
if (j == 15) {
printf("'\\x%02X'", keys[i][j]);
} else {
printf("'\\x%02X', ", keys[i][j]);
}
}
if (i == 3) {
printf("}};\n");
} else {
printf("},\n");
}
}
// PP the cipher texts.
for (int i = 0; i < 4; i++) {
printf("static const unsigned char cipher[80] = {");
for (int j = 0; j < 80; j++) {
if (j == 79) {
printf("'\\x%02X'};\n", cipher[i][j]);
} else {
printf("'\\x%02X', ", cipher[i][j]);
}
}
}
return 0;
}
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