tomato/other/fun/sign.c
Green Sky 227425b90e Squashed 'external/toxcore/c-toxcore/' content from commit 67badf69
git-subtree-dir: external/toxcore/c-toxcore
git-subtree-split: 67badf69416a74e74f6d7eb51dd96f37282b8455
2023-07-25 11:53:09 +02:00

148 lines
3.6 KiB
C

/* Binary signer/checker using ed25519
*
* Compile with:
* gcc -o sign sign.c -lsodium
*
* Generate a keypair:
* ./sign g
*
* Sign a file:
* ./sign s PRIVATEKEY file.bin signedfile.bin
*
* Check a file:
*
* ./sign c PUBKEY signedfile.bin
*
* NOTE: The signature is appended to the end of the file.
*/
#include <sodium.h>
#include <string.h>
#include "../../testing/misc_tools.h" // hex_string_to_bin
#include "../../toxcore/ccompat.h"
static int load_file(char *filename, unsigned char **result)
{
int size = 0;
FILE *f = fopen(filename, "rb");
if (f == nullptr) {
*result = nullptr;
return -1; // -1 means file opening fail
}
fseek(f, 0, SEEK_END);
size = ftell(f);
fseek(f, 0, SEEK_SET);
*result = (unsigned char *)malloc(size + 1);
if (size != fread(*result, sizeof(char), size, f)) {
free(*result);
fclose(f);
return -2; // -2 means file reading fail
}
fclose(f);
(*result)[size] = 0;
return size;
}
int main(int argc, char *argv[])
{
unsigned char pk[crypto_sign_ed25519_PUBLICKEYBYTES];
unsigned char sk[crypto_sign_ed25519_SECRETKEYBYTES];
if (argc == 2 && argv[1][0] == 'g') {
crypto_sign_ed25519_keypair(pk, sk);
printf("Public key:\n");
for (int i = 0; i < crypto_sign_ed25519_PUBLICKEYBYTES; ++i) {
printf("%02X", pk[i]);
}
printf("\nSecret key:\n");
for (int i = 0; i < crypto_sign_ed25519_SECRETKEYBYTES; ++i) {
printf("%02X", sk[i]);
}
printf("\n");
}
if (argc == 5 && argv[1][0] == 's') {
unsigned char *secret_key = hex_string_to_bin(argv[2]);
unsigned char *data = nullptr;
int size = load_file(argv[3], &data);
if (size < 0) {
goto fail;
}
unsigned long long smlen;
unsigned char *sm = (unsigned char *)malloc(size + crypto_sign_ed25519_BYTES * 2);
crypto_sign_ed25519(sm, &smlen, data, size, secret_key);
free(data);
free(secret_key);
if (smlen - size != crypto_sign_ed25519_BYTES) {
free(sm);
goto fail;
}
FILE *f = fopen(argv[4], "wb");
if (f == nullptr) {
free(sm);
goto fail;
}
memcpy(sm + smlen, sm, crypto_sign_ed25519_BYTES); // Move signature from beginning to end of file.
if (fwrite(sm + (smlen - size), 1, smlen, f) != smlen) {
fclose(f);
free(sm);
goto fail;
}
fclose(f);
free(sm);
printf("Signed successfully.\n");
}
if (argc == 4 && argv[1][0] == 'c') {
unsigned char *public_key = hex_string_to_bin(argv[2]);
unsigned char *data;
int size = load_file(argv[3], &data);
if (size < 0) {
goto fail;
}
unsigned char *signe = (unsigned char *)malloc(size + crypto_sign_ed25519_BYTES);
memcpy(signe, data + size - crypto_sign_ed25519_BYTES,
crypto_sign_ed25519_BYTES); // Move signature from end to beginning of file.
memcpy(signe + crypto_sign_ed25519_BYTES, data, size - crypto_sign_ed25519_BYTES);
free(data);
unsigned char *m = (unsigned char *)malloc(size);
unsigned long long mlen;
if (crypto_sign_ed25519_open(m, &mlen, signe, size, public_key) == -1) {
printf("Failed checking sig.\n");
free(m);
free(signe);
goto fail;
}
free(m);
free(signe);
printf("Checked successfully.\n");
}
return 0;
fail:
printf("FAIL\n");
return 1;
}