(Unicode C++) Get a Certificate's Key Size

Demonstrates how to get the RSA key size of a certificate (for example, 1024-bit, 2048-bit, etc.)

Note: This example requires Chilkat v11.0.0 or greater.

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#include <CkStringBuilderW.h>
#include <CkCertW.h>
#include <CkPublicKeyW.h>
#include <CkXmlW.h>
#include <CkBinDataW.h>

void ChilkatSample(void)
    {
    bool success = false;

    // For this example, I have a certificate in raw base64 format (not PEM),
    // that looks like this:  "MIIGkDCCBHigAwIBAgIUMDA ... s/iqLsLA=="
    CkStringBuilderW sbCertBase64;
    success = sbCertBase64.LoadFile(L"qa_data/certs/base64Cert.txt",L"utf-8");

    CkCertW cert;
    success = cert.LoadFromBase64(sbCertBase64.getAsString());
    if (success == false) {
        wprintf(L"%s\n",cert.lastErrorText());
        return;
    }

    // Get the public key.
    CkPublicKeyW pubKey;
    cert.GetPublicKey(pubKey);

    int numBits = pubKey.get_KeySize();
    wprintf(L"Number of bits = %d\n",numBits);

    // If using an older version of Chilkat, the key size can be obtained like this:
    CkXmlW xml;
    xml.LoadXml(pubKey.getXml());

    CkBinDataW binDat;
    binDat.AppendEncoded(xml.getChildContent(L"Modulus"),L"base64");

    numBits = 8 * binDat.get_NumBytes();
    wprintf(L"Number of bits = %d\n",numBits);
    }