Seems like the problem disapeared now, even thought I cannot exactly tell why. Seems like I messed up some of that ugly pointer stuff that now works fine after some changes in the code.
Again, thanks for your help.

Thanks and regards
Till Elsner

Am 08.04.2008 um 09:04 schrieb shankar ks:

Hi Till,
The error u got is you can not read the public key as in the certificate it is not finding the lines as "BEGIN RSA CERTIFICATE" so here i am giving you the code , use it directly , it will work fine as i refined it many times ...

pubk = RSA_new();
if(pubk == NULL)
printf("error to create new RSA structure \n");

fp = fopen (recevercert, "r");
if (fp == NULL){
printf("error opening the pub file\n");
exit (1);
}
x509 = PEM_read_X509(fp, NULL, NULL, NULL);
fclose (fp);


if (x509 == NULL) {
printf("error reading the certificate \n");
ERR_print_errors_fp (stderr);
exit (1);
}

pub=X509_get_pubkey(x509);
if (pub == NULL) {
printf("error reading the public key \n");
ERR_print_errors_fp (stderr);
exit (1);
}

pubk = EVP_PKEY_get1_RSA(pub);
if(pub == NULL)
printf("error setting the public key from EVP_PKEY_set1_RSA function \n");

----
after this you do encryption and decryption , then it will work fine, one more thing here is you should not use RSA_encrypt or decrypt functions for large amount of data , it is not recommended , so u must avoid of using asymmetric alrorithems for large amount of data or for files .. or I recommend not to use it for any data or file except for encryption of keys only.


-- Regards
Shankar



On 4/8/08, Till Elsner <[EMAIL PROTECTED]> wrote:
Hi,

I'm trying to make an application encypting data on the server side using a public key and decrypting it on the client side using the related private key. Now i've run in two problems: I have a private key and a related certificate file created from a certificate request (CSR) and signed by an own CA. Both are created using OpenSSL. The first problem is that I can't get the public key out of the cerificate using PEM_read_RSA_PUBKEY. I've exported the public key alone to a single file, from that I can load the public key. Trying to load it from the certificate gives an "no starting line" error. Second, and maybe even worse, when encrypting data with the public key using RSA_public_encrypt and again decrypting it with the private one using RSA_private_decrypt, the decrypted data differs widely from the original data. When I try the same using OpenSSL's rsautl command-line tool, it works perfectly with this key pair (public key/private key as well as certificate/private key). Both keys and certificate are in PEM format. The certificates signature is valid.
Could anyone give me some hint what might be going on here?

Thanks and regards
Till Elsner
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--
--Best Regards
Shankar

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