1#include <stdio.h>
2#include <openssl/rsa.h>
3
4/* This is a simple program to generate an RSA private key.  It then
5 * saves both the public and private key into a char array, then
6 * re-reads them.  It saves them as DER encoded binary data.
7 */
8
9void callback(stage,count,arg)
10int stage,count;
11char *arg;
12	{
13	FILE *out;
14
15	out=(FILE *)arg;
16	fprintf(out,"%d",stage);
17	if (stage == 3)
18		fprintf(out,"\n");
19	fflush(out);
20	}
21
22main()
23	{
24	RSA *rsa,*pub_rsa,*priv_rsa;
25	int len;
26	unsigned char buf[1024],*p;
27
28	rsa=RSA_generate_key(512,RSA_F4,callback,(char *)stdout);
29
30	p=buf;
31
32	/* Save the public key into buffer, we know it will be big enough
33	 * but we should really check how much space we need by calling the
34	 * i2d functions with a NULL second parameter */
35	len=i2d_RSAPublicKey(rsa,&p);
36	len+=i2d_RSAPrivateKey(rsa,&p);
37
38	printf("The public and private key are now both in a char array\n");
39	printf("and are taking up %d bytes\n",len);
40
41	RSA_free(rsa);
42
43	p=buf;
44	pub_rsa=d2i_RSAPublicKey(NULL,&p,(long)len);
45	len-=(p-buf);
46	priv_rsa=d2i_RSAPrivateKey(NULL,&p,(long)len);
47
48	if ((pub_rsa == NULL) || (priv_rsa == NULL))
49		ERR_print_errors_fp(stderr);
50
51	RSA_free(pub_rsa);
52	RSA_free(priv_rsa);
53	}
54