blob: 586d174901d1020a2e8a1ad67ab2ac1529f4f69f (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
#include "../lib/lib.h"
#include "../lib/lib2.h"
#include <time.h>
/**
* This time there is a random amount of random data before our
* data. This is that annoys us. If we would one where our data
* would begin all would be fine, we would do the same as in task12
* But since we are using ECB blocks din't change with the random data.
* So we make a first request with our data empty and than make a second
* request with one byte. Than we compere the results. The blocks which
* contain the random data keep the same, exceot the last, because we
* probably append our byte into that block instead of the first byte of
* our target string. Now we now how many blocks of random data are before
* our data.
* To get the excat number of bytes, we add two blocksof A's. So one block is
* for sure filled just with A's. Than we remove A's until the block of A's
* change because our traget data get into it. Then blocksize-Removed A's
* is the offset block where our data start.
* 16*unchanged_blocks + BLOKCSIZE-RemovedA's
*
*
**/
#define BLOCKSIZE 16
int main(int argc, char **argv)
{
srand(time(NULL));
generate_random_bytes(key, 16);
// cleartext + maybe an additional block
int prepended_data_len = aes_ecb_detect_prepended_data();
printf("prepended data len: %i\n", prepended_data_len);
// so now we now the offset where our data get inserted
// ignoring everything befor offset we now have to do the same
// as in task12
// well in task13 we make the assumtion that we start at a fresh block
// so maybe at some garbage to fill the rest block
char *plaintext;
crack_aes_ecb(&plaintext, 16, prepended_data_len);
printf("recovered data:\n%s\n", plaintext);
}
|
