Ciao

—————————–keygenv2.c——————————–
/*
Simple RSA Key generator. Saves keys in PEM format. Updated to openSSL 0.9.8k.
Coded by Paolo Ardoino –
Alessandro Baroni –
Compile: gcc -lssl keygen.c -o keygen
Usage: ./keygen
Ex. ./keygen 1024

*/

#include
#include
#include
#include

#define SECFILE “sec.pem”
#define PUBFILE “pub.pem”

int main(int argc, char *argv[]){
FILE *fp=NULL;
RSA *key = NULL;
BIGNUM *e = BN_new();
int keylen=0;

if(argc!=2){
fprintf(stderr,”Error: too many/few arguments.\n ”
“Usage: %s \n”,argv[0]);
exit(0);
}
keylen = atoi(argv[1]);

BN_set_word(e, 65537);
key = RSA_new();

if( !RSA_generate_key_ex(key, keylen, e, NULL) ){
fprintf(stderr,”%s\n”,ERR_error_string(ERR_get_error(),NULL));
exit(-1);
}

if(RSA_check_key(key) < 1){
fprintf(stderr,”Error: Problems while generating RSA Key.\nRetry.\n”);
exit(-1);
}

fp=fopen(SECFILE,”w”);
if(PEM_write_RSAPrivateKey(fp,key,NULL,NULL,0,0,NULL) == 0){
fprintf(stderr,”Error: problems while writing RSA Private Key.\n”);
exit(-1);
}
fclose(fp);

fp=fopen(PUBFILE,”w”);
if(PEM_write_RSAPublicKey(fp,key) == 0){
fprintf(stderr,”Error: problems while writing RSA Public Key.\n”);
exit(-1);
}
fclose(fp);

BN_free(e);
RSA_free(key);

return 0;
}