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

See more Apple Keychain Examples

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 <C_CkCertW.h>
#include <C_CkBinDataW.h>
#include <C_CkRsaW.h>

void ChilkatSample(void)
    {
    HCkCertW cert;
    BOOL success;
    HCkBinDataW bd;
    int i;
    HCkRsaW rsa;
    HCkBinDataW bdSig;

    // 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.

    cert = CkCertW_Create();

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

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

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

    // Create data to be hashed and signed.
    bd = CkBinDataW_Create();

    for (i = 0; i <= 100; i++) {
        CkBinDataW_AppendEncoded(bd,L"000102030405060708090A0B0C0D0E0F",L"hex");
    }

    rsa = CkRsaW_Create();

    // Use the certificate's private key for signing.
    success = CkRsaW_SetX509Cert(rsa,cert,TRUE);
    if (success == FALSE) {
        wprintf(L"%s\n",CkRsaW_lastErrorText(rsa));
        CkCertW_Dispose(cert);
        CkBinDataW_Dispose(bd);
        CkRsaW_Dispose(rsa);
        return;
    }

    // Sign the SHA-256 hash of the contents of bd.
    bdSig = CkBinDataW_Create();
    success = CkRsaW_SignBd(rsa,bd,L"sha256",bdSig);
    if (success == FALSE) {
        wprintf(L"%s\n",CkRsaW_lastErrorText(rsa));
        CkCertW_Dispose(cert);
        CkBinDataW_Dispose(bd);
        CkRsaW_Dispose(rsa);
        CkBinDataW_Dispose(bdSig);
        return;
    }

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

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

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


    CkCertW_Dispose(cert);
    CkBinDataW_Dispose(bd);
    CkRsaW_Dispose(rsa);
    CkBinDataW_Dispose(bdSig);

    }