gnutls_certificate_set_x509_key_mem - Linux


The gnutls_certificate_set_x509_key_mem function sets the private key of an X.509 certificate using the data in allocated memory. It is commonly used for loading private keys from memory when creating or manipulating X.509 certificates.


gnutls_certificate_set_x509_key_mem(certificate, key, key_length)


| Option | Description | Default |
| certificate | An existing X.509 certificate object. | |
| key | Pointer to the allocated memory containing the private key data. | |
| key_length | The length of the private key data in bytes. | |


Example 1: Loading a private key from memory

#include <gnutls/gnutls.h>
#include <stdio.h>
#include <stdlib.h>

int main() {
    gnutls_certificate_t cert;
    unsigned char key[1024]; // Assuming a key size of 1024 bytes

    // Load the certificate
    gnutls_certificate_load_file(&cert, "cert.pem", GNUTLS_X509_FMT_PEM);

    // Set the private key from memory
    gnutls_certificate_set_x509_key_mem(&cert, key, sizeof(key));

    // Print certificate information
    gnutls_certificate_print(&cert, GNUTLS_CRT_PRINT_FULL);

    return 0;

Common Issues

  • Incorrect key format: Ensure that the private key data is in the correct format compatible with the certificate.
  • Insufficient key length: Verify that the key_length parameter matches the actual length of the private key data.
  • Memory errors: Handle memory allocation and management properly to avoid memory-related issues.


The gnutls_certificate_set_x509_key_mem function can be used in conjunction with other GnuTLS functions for advanced X.509 certificate handling tasks, such as:

  • Generating new X.509 certificates with private keys
  • Verifying X.509 certificates using a loaded private key
  • Creating secure communication channels using X.509 certificates

Related Commands

  • gnutls_certificate_new: Creates a new X.509 certificate object.
  • gnutls_certificate_import_key: Imports a private key from a file or memory buffer.
  • gnutls_certificate_verify_peers: Verifies X.509 certificates for peer authentication.