byte* rsa_oaep_decrypt(const rsa_priv_t key, const byte *msg, size_t len, size_t *rlen) {
// rsa_dcr should be OAEP_LEN long if this is really OAEP
byte *rsa_dcr = rsa_decrypt_block(key, msg, len, NULL);
byte *oaep_dcr = oaep_decode(rsa_dcr, rlen);
free(rsa_dcr);
return oaep_dcr;
}
int main(int argc, char *argv[]) {
if (argc != 3) {
fprintf(stderr, "usage: %s priv_file pub_file\n", argv[0]);
return EXIT_FAILURE;
}
byte msg[] = "It's not the red of the dying sun /"
" The morning sheets surprising stain /"
" It's not the red of which we bleed /"
" The red of cabernet sauvignon /"
" A world of ruby all in vain /"
" It's not that red /"
" It's not as golden as Zeus famous shower /"
" It doesn't, not at a";
char *priv_name = argv[1];
char *pub_name = argv[2];
rsa_keypair_t kp;
FILE *pub = fopen(pub_name, "rb");
FILE *priv = fopen(priv_name, "rb");
if (!pub || !priv) {
fputs("error: cannot open key files for reading\n", stderr);
return EXIT_FAILURE;
}
bool failed = !rsa_read_pubkey(&kp.pub, pub) || !rsa_read_privkey(&kp.priv, priv);
fclose(pub);
fclose(priv);
if (failed) {
fputs("error: cannot read keys\n", stderr);
return EXIT_FAILURE;
}
puts((char*) msg);
bytes_n_dump(msg, RSA_KEY);
puts("");
size_t rlen;
rsa_encrypt_block(kp.pub, msg, sizeof msg, &rlen);
bytes_n_dump(msg, rlen);
puts("");
rsa_decrypt_block(kp.priv, msg, rlen, &rlen);
bytes_n_dump(msg, rlen);
printf("\n%s\n", (char*) msg);
}
int main()
{
int ret = 0;
size_t len = STR_LEN;
char E[STR_LEN], D[STR_LEN], N[STR_LEN];
uchar source[MSG_LEN];
uchar encrypted[MSG_LEN], decrypted[MSG_LEN]; // Buffers
public_key pub;
private_key priv;
MPI_CHK(rsa_generate_keys(65537, pub, priv, 1024));
MPI_CHK(mpi_write_string(&pub.e, 10, E, &len));
len = STR_LEN;
MPI_CHK(mpi_write_string(&pub.n, 10, N, &len));
len = STR_LEN;
MPI_CHK(mpi_write_string(&priv.d, 10, D, &len));
printf("e = %s\nd = %s\nn = %s\n", E, D, N);
printf("Enter message to encrypt:\n");
scanf("%[^\n]", source);
len = strnlen((const char *)source, MSG_LEN) + 1; // Length of string + zero-char
try
{
MPI_CHK(rsa_encrypt_block(source, len, encrypted, MSG_LEN, pub));
print_buffer("Encrypted", encrypted, MSG_LEN);
MPI_CHK(rsa_decrypt_block(encrypted, MSG_LEN, decrypted, MSG_LEN, priv));
print_buffer("Decrypted", decrypted, MSG_LEN);
MPI_CHK(rsa_sign_block(source, len, encrypted, MSG_LEN, priv));
print_buffer("Signature", encrypted, MSG_LEN);
MPI_CHK(rsa_check_block(encrypted, MSG_LEN, decrypted, MSG_LEN, pub));
print_buffer("Preimage", decrypted, MSG_LEN);
source[0] = InvertBit(source[0], 2);
printf("Corrupted:\n%s\n\n", source);
MPI_CHK(rsa_sign_block(source, len, encrypted, MSG_LEN, priv));
print_buffer("Signature of corrupted", encrypted, MSG_LEN);
}
catch (char *e)
{
printf("Error: %s\n", e);
}
cleanup:
mpi_free(&pub.e);
mpi_free(&priv.d);
mpi_free(&priv.n);
return ret;
}
