Getting a Certificate for Schannel

The following example shows the steps to obtain a CERT_CONTEXT structure that contains a certificate; you should select a certificate and certificate store that are appropriate for your application.

This example demonstrates opening a certificate store and locating a certificate that will be passed to the AcquireCredentialsHandle function, by means of the SCHANNEL_CRED structure.


#include <windows.h>
#include <stdio.h>
#pragma comment(lib, "crypt32.lib")

#define MACHINE_NAME "example server"

PCCERT_CONTEXT getServerCertificate ()
{
  HCERTSTORE hMyCertStore = NULL;
  PCCERT_CONTEXT aCertContext = NULL;
  
  //-------------------------------------------------------
  // Open the My store, also called the personal store.
  // This call to CertOpenStore opens the Local_Machine My 
  // store as opposed to the Current_User's My store.

    hMyCertStore = CertOpenStore(CERT_STORE_PROV_SYSTEM,
                                 X509_ASN_ENCODING,
                                 0,
                                 CERT_SYSTEM_STORE_LOCAL_MACHINE,
                                 L"MY");

  if (hMyCertStore == NULL) 
  {
    printf("Error opening MY store for server.\n");
    goto cleanup;
  }
  //-------------------------------------------------------
  // Search for a certificate with some specified
  // string in it. This example attempts to find
  // a certificate with the string "example server" in
  // its subject string. Substitute an appropriate string
  // to find a certificate for a specific user.

  aCertContext = CertFindCertificateInStore(hMyCertStore, 
                  X509_ASN_ENCODING, 
                  0,
                  CERT_FIND_SUBJECT_STR_A,
                  MACHINE_NAME, // use appropriate subject name
                  NULL
  );
  
  if (aCertContext == NULL)
  {
    printf("Error retrieving server certificate.");
    goto cleanup;
  }
cleanup:
  if(hMyCertStore)
  {
      CertCloseStore(hMyCertStore,0);
  }
  return aCertContext;
}


 

 

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