(Unicode C++) RSA Sign using a Private Key on a USB Token or Smartcard

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Create an RSA signature using a private key stored on a USB token or smartcard.

Note: On MacOS and iOS, this example requires Chilkat v10.1.2 or later when the Apple Keychain is used as the underlying means to do the signing.

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#include <CkCertW.h>
#include <CkBinDataW.h>
#include <CkRsaW.h>

void ChilkatSample(void)
    {
    // Assuming the smartcard/USB token is installed with the correct drivers from the manufacturer,
    // this code can work on multiple platforms including Windows, MacOS, Linux, and iOS.

    // Chilkat automatically detects and determines the way in which the HSM is used,
    // which can be by PKCS11, Apple Keychain, Microsoft CNG / Crypto API, or ScMinidriver.

    CkCertW cert;

    // Set the token/smartcard PIN prior to loading.
    cert.put_SmartCardPin(L"123456");

    // Specify the certificate by its common name.
    bool success = cert.LoadFromSmartcard(L"cn=chilkat-rsa-2048");
    if (success == false) {
        wprintf(L"%s\n",cert.lastErrorText());
        return;
    }

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

    // Create data to be hashed and signed.
    CkBinDataW bd;
    int i;
    for (i = 0; i <= 100; i++) {
        bd.AppendEncoded(L"000102030405060708090A0B0C0D0E0F",L"hex");
    }

    CkRsaW rsa;

    // Use the certificate's private key for signing.
    success = rsa.SetX509Cert(cert,true);
    if (success == false) {
        wprintf(L"%s\n",rsa.lastErrorText());
        return;
    }

    // Sign the SHA-256 hash of the contents of bd.
    CkBinDataW bdSig;
    success = rsa.SignBd(bd,L"sha256",bdSig);
    if (success == false) {
        wprintf(L"%s\n",rsa.lastErrorText());
        return;
    }

    // The RSA signature is equal in length to the size of the RSA key.
    wprintf(L"Output signature size in bits = %d\n",bdSig.get_NumBytes() * 8);

    // We can save the signature for later verification..
    bdSig.WriteFile(L"rsaSignatures/test1.sig");

    // See the example to verify the RSA signature:
    // Verfies an RSA Signature
    }