(Unicode C) How to Parse a X.509 Certificate and Extract its Public Key

Demonstrates how to load an X.509 certificate and extract the public key. Chilkat supports many certificate encodings:

• DER (binary) encoded certificates (.crt/.cer)
• PEM (BASE64) encoded certificates (.pem)
• Load Certificates Directly from Windows Certificate Stores
• PFX/PKCS12 (.pfx/.p12)
• Java KeyStore (.jks)
• Cryptographic Message Syntax Standard - PKCS #7 Certificates (.P7B)

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#include <C_CkCertW.h>
#include <C_CkPublicKeyW.h>

void ChilkatSample(void)
    {
    HCkCertW cert;
    BOOL success;
    HCkPublicKeyW pubKey;

    cert = CkCertW_Create();

    // Load a DER (binary) encoded certificate.
    // To load from a .pem or .p7b, or any other file format that contains
    // just one certificate, call LoadFromFile in exactly the same way.
    // The LoadFromFile method automatically detects the format and loads the certificate.
    success = CkCertW_LoadFromFile(cert,L"qa_data/certs/testCert.cer");
    if (success == FALSE) {
        wprintf(L"%s\n",CkCertW_lastErrorText(cert));
        CkCertW_Dispose(cert);
        return;
    }

    // Get the public key:
    pubKey = CkCertW_ExportPublicKey(cert);
    if (CkCertW_getLastMethodSuccess(cert) != TRUE) {
        wprintf(L"%s\n",CkCertW_lastErrorText(cert));
        CkCertW_Dispose(cert);
        return;
    }

    // Examine the key type.
    // A PublicKey object can contain an RSA, ECC, or DSA public key.
    // The KeyType property will contain "rsa", "ecc", or "dsa".
    wprintf(L"key type = %s\n",CkPublicKeyW_keyType(pubKey));

    CkPublicKeyW_Dispose(pubKey);


    CkCertW_Dispose(cert);

    }