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#include "../lib/lib.h"
#include "../lib/lib2.h"
#include "../lib/lib3.h"
#include "../lib/lib4.h"
#include <time.h>
int main(int argc, char **argv)
{
if(argc != 2)
printf("Please provide ONE key as argument!\n");
uint32_t *hmac;
uint32_t *hmac2;
int i;
unsigned char *text = "comment1=cooking%20MCs;userdata=foo;comment2=%20like%20a%20pound%20of%20bacon";
unsigned char *append = ";admin=true";
unsigned char *key = argv[1];
printf("Using secret key: %s\n", key);
unsigned char *padded;
int padding_len = md4_padding(strlen(key)+strlen(text), &padded);
printf("MD4 padding is:\n");
for(i=0;i<padding_len;i++)
printf("%02x", padded);
md4_prefix_key_mac(&hmac, text, strlen(text), key, strlen(key));
printf("MAC of original message:\n");
for(i=0;i<5;i++)
printf("%02x", hmac[i]);
printf("\n");
/*
* We are appending a text to the original message without knowign the
* key. Actually we don't know the message here, just the hash of the orginal
* message. We have to append the right padding here, e.g. the size of the
* *complete* message, not only append
*/
unsigned int new_msg_len = strlen(text)+strlen(append)+padding_len;
unsigned char *new_msg = malloc(new_msg_len);
memcpy(new_msg, text, strlen(text));
memcpy(&new_msg[strlen(text)], padded, padding_len);
memcpy(&new_msg[strlen(text)+padding_len], append, strlen(append));
unsigned char *padding2;
// mesage + padding + append + padding
int padding2_len = md4_padding(new_msg_len+strlen(key), &padding2);
unsigned char *tmp2 = malloc(strlen(append)+padding2_len);
memcpy(tmp2, append, strlen(append));
memcpy(&tmp2[strlen(append)], padding2, padding2_len);
md4_prefix_key_forge(&hmac2, tmp2, (strlen(append)+padding2_len), hmac);
printf("MAC of forged message:\n");
for(i=0;i<5;i++)
printf("%02x", hmac2[i]);
printf("\n");
/*
* create the message we forged. Send this plus the hmac to the
* victim. He knows the secret and test and will think that
* this is a message from Alice
*/
printf("Verifying...\n");
if(md4_prefix_key_verify(hmac2, new_msg, new_msg_len, key, strlen(key)))
printf("Forged MAC got accepted!\n");
}
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