Green Sky
227425b90e
git-subtree-dir: external/toxcore/c-toxcore git-subtree-split: 67badf69416a74e74f6d7eb51dd96f37282b8455
85 lines
1.9 KiB
C
85 lines
1.9 KiB
C
/* Public key cracker.
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*
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* Can be used to find public keys starting with specific hex (ABCD) for example.
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*
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* NOTE: There's probably a way to make this faster.
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*
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* Usage: ./cracker ABCDEF
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*
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* Will try to find a public key starting with: ABCDEF
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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/* Sodium includes*/
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#include <sodium/crypto_scalarmult_curve25519.h>
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#include <sodium/randombytes.h>
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#include "../../testing/misc_tools.h"
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#include "../../toxcore/ccompat.h"
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// Secret key and public key length
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#define KEY_LEN 32
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static void print_key(const uint8_t *client_id)
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{
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for (int j = 0; j < KEY_LEN; ++j) {
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printf("%02X", client_id[j]);
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}
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}
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int main(int argc, char *argv[])
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{
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if (argc < 2) {
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printf("usage: ./cracker public_key(or beginning of one in hex format)\n");
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return 0;
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}
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long long unsigned int num_tries = 0;
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size_t len = strlen(argv[1]) / 2;
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unsigned char *key = hex_string_to_bin(argv[1]);
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uint8_t pub_key[KEY_LEN], priv_key[KEY_LEN], c_key[KEY_LEN];
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if (len > KEY_LEN) {
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printf("%zu characters given, truncating to: %d\n", len * 2, KEY_LEN * 2);
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len = KEY_LEN;
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}
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memcpy(c_key, key, len);
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free(key);
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randombytes(priv_key, KEY_LEN);
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while (1) {
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crypto_scalarmult_curve25519_base(pub_key, priv_key);
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if (memcmp(c_key, pub_key, len) == 0) {
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break;
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}
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/*
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* We can't use the first and last bytes because they are masked in
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* curve25519. Using them would generate duplicate keys.
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*/
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for (int i = (KEY_LEN - 1); i > 1; --i) {
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priv_key[i - 1] += 1;
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if (priv_key[i - 1] != 0) {
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break;
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}
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}
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++num_tries;
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}
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printf("Public key:\n");
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print_key(pub_key);
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printf("\nPrivate key:\n");
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print_key(priv_key);
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printf("\n %llu keys tried\n", num_tries);
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return 0;
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}
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