(Unicode C++) RSA Sign String using Private Key of Certificate Type A3 (smart card / token)

Demonstrates RSA signing a string using the private key of a certificate type A3 (smart card, token).

Note: This is a Windows-only example.

Note: This example requires Chilkat v10.1.2 or greater.

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#include <CkCertStoreW.h>
#include <CkJsonObjectW.h>
#include <CkCertW.h>
#include <CkRsaW.h>

void ChilkatSample(void)
    {
    // First get the A3 certificate that was installed on the Windows system.
    CkCertStoreW certStore;

    const wchar_t *thumbprint = L"12c1dd8015f3f03f7b1fa619dc24e2493ca8b4b2";

    // This is specific to Windows because it is opening the Windows Current-User certificate store.
    bool bReadOnly = true;
    bool success = certStore.OpenCurrentUserStore(bReadOnly);
    if (success != true) {
        wprintf(L"%s\n",certStore.lastErrorText());
        return;
    }

    // Find the certificate with the desired thumbprint
    // (There are many ways to locate a certificate.  This example chooses to find by thumbprint.)
    CkJsonObjectW json;
    json.UpdateString(L"thumbprint",thumbprint);

    CkCertW cert;
    success = certStore.FindCert(json,cert);
    if (success == false) {
        wprintf(L"Failed to find the certificate.\n");
        return;
    }

    wprintf(L"Found: %s\n",cert.subjectCN());

    CkRsaW rsa;

    // Provide the cert's private key
    bool bUsePrivateKey = true;
    success = rsa.SetX509Cert(cert,bUsePrivateKey);
    if (success != true) {
        wprintf(L"%s\n",rsa.lastErrorText());
        return;
    }

    // Return the RSA signature in base64 encoded form.
    rsa.put_EncodingMode(L"base64");

    // Sign the utf-8 byte representation of the string.
    rsa.put_Charset(L"utf-8");

    // You can also choose other hash algorithms, such as SHA-1.
    const wchar_t *sigBase64 = rsa.signStringENC(L"text to sign",L"SHA-256");
    if (rsa.get_LastMethodSuccess() != true) {
        wprintf(L"%s\n",rsa.lastErrorText());
        return;
    }

    wprintf(L"Base64 signature: %s\n",sigBase64);
    }