int main(int argc, char *argv[])
{
int opt, modbits;
FILE *ofp = stdout;
mp_result res;
find_f find_func = find_prime;
char tag = 'p';
mpz_t value;
/* Process command-line arguments */
while((opt = getopt(argc, argv, "s")) != EOF) {
switch(opt) {
case 's':
find_func = find_strong_prime;
tag = 'P';
break;
default:
fprintf(stderr, "Usage: randprime [-s] <bits> [<outfile>]\n");
return 1;
}
}
if(optind >= argc) {
fprintf(stderr, "Error: You must specify the number of significant bits.\n");
fprintf(stderr, "Usage: randprime [-s] <bits> [<outfile>]\n");
return 1;
}
modbits = (int) strtol(argv[optind++], NULL, 0);
if(modbits < CHAR_BIT) {
fprintf(stderr, "Error: Invalid value for number of significant bits.\n");
return 1;
}
if(modbits % 2 == 1)
++modbits;
/* Check if output file is specified */
if(optind < argc) {
if((ofp = fopen(argv[optind], "wt")) == NULL) {
fprintf(stderr, "Error: Unable to open output file for writing.\n"
" - Filename: %s\n"
" - Error: %s\n", argv[optind], strerror(errno));
return 1;
}
}
mp_int_init(&value);
if ((res = mp_int_randomize(&value, modbits - 1)) != MP_OK) {
fprintf(stderr, "Error: Unable to generate random start value.\n"
" - %s (%d)\n", mp_error_string(res), res);
goto EXIT;
}
fprintf(stderr, "%c: ", tag);
find_func(&value, stderr);
fputc('\n', stderr);
/* Write the completed value to the specified output file */
{
int len;
char *obuf;
len = mp_int_string_len(&value, 10);
obuf = malloc(len);
mp_int_to_string(&value, 10, obuf, len);
fputs(obuf, ofp);
fputc('\n', ofp);
free(obuf);
}
EXIT:
fclose(ofp);
mp_int_clear(&value);
return 0;
}
int main(int argc, char *argv[])
{
int opt, modbits;
FILE *ofp = stdout;
char *expt = NULL;
rsa_key the_key;
mp_result res;
/* Process command-line arguments */
while((opt = getopt(argc, argv, "e:")) != EOF) {
switch(opt) {
case 'e':
expt = optarg;
break;
default:
fprintf(stderr, "Usage: rsakey [-e <expt>] <modbits> [<outfile>]\n");
return 1;
}
}
if(optind >= argc) {
fprintf(stderr, "Error: You must specify the number of modulus bits.\n");
fprintf(stderr, "Usage: rsakey [-e <expt>] <modbits> [<outfile>]\n");
return 1;
}
modbits = (int) strtol(argv[optind++], NULL, 0);
if(modbits < CHAR_BIT) {
fprintf(stderr, "Error: Invalid value for number of modulus bits.\n");
return 1;
}
if(modbits % 2 == 1)
++modbits;
/* Check if output file is specified */
if(optind < argc) {
if((ofp = fopen(argv[optind], "wt")) == NULL) {
fprintf(stderr, "Error: Unable to open output file for writing.\n"
" - Filename: %s\n"
" - Error: %s\n", argv[optind], strerror(errno));
return 1;
}
}
if((res = rsa_key_init(&the_key)) != MP_OK) {
fprintf(stderr, "Error initializing RSA key structure:\n"
" - %s (%d)\n", mp_error_string(res), res);
return 1;
}
/* If specified, try to load the key exponent */
if(expt != NULL) {
if((res = mp_int_read_string(&(the_key.e), 10, expt)) != MP_OK) {
fprintf(stderr, "Error: Invalid value for encryption exponent.\n"
" - %s (%d)\n", mp_error_string(res), res);
goto EXIT;
}
}
if((res = mp_int_randomize(&(the_key.p), (modbits / 2))) != MP_OK) {
fprintf(stderr, "Error: Unable to randomize first prime.\n"
" - %s (%d)\n", mp_error_string(res), res);
goto EXIT;
}
fprintf(stderr, "p: ");
find_prime(&(the_key.p), stderr);
if((res = mp_int_randomize(&(the_key.q), (modbits / 2))) != MP_OK) {
fprintf(stderr, "Error: Unable to randomize second prime.\n"
" - %s (%d)\n", mp_error_string(res), res);
goto EXIT;
}
fprintf(stderr, "\nq: ");
find_prime(&(the_key.q), stderr);
fputc('\n', stderr);
/* Temporarily, the key's "n" field will be (p - 1) * (q - 1) for
purposes of computing the decryption exponent.
*/
mp_int_mul(&(the_key.p), &(the_key.q), &(the_key.n));
mp_int_sub(&(the_key.n), &(the_key.p), &(the_key.n));
mp_int_sub(&(the_key.n), &(the_key.q), &(the_key.n));
mp_int_add_value(&(the_key.n), 1, &(the_key.n));
if(expt == NULL &&
(res = mp_int_randomize(&(the_key.e), (modbits / 2))) != MP_OK) {
fprintf(stderr, "Error: Unable to randomize encryption exponent.\n"
" - %s (%d)\n", mp_error_string(res), res);
goto EXIT;
}
while((res = mp_int_invmod(&(the_key.e), &(the_key.n),
&(the_key.d))) != MP_OK) {
if(expt != NULL) {
fprintf(stderr, "Error: Unable to compute decryption exponent.\n"
" - %s (%d)\n", mp_error_string(res), res);
goto EXIT;
}
if((res = mp_int_randomize(&(the_key.e), (modbits / 2))) != MP_OK) {
fprintf(stderr, "Error: Unable to re-randomize encryption exponent.\n"
" - %s (%d)\n", mp_error_string(res), res);
goto EXIT;
}
}
/* Recompute the real modulus, now that exponents are done. */
mp_int_mul(&(the_key.p), &(the_key.q), &(the_key.n));
/* Write completed key to the specified output file */
rsa_key_write(&the_key, ofp);
EXIT:
fclose(ofp);
rsa_key_clear(&the_key);
return 0;
}