(Unicode C) Duplicate openssl dgst -sha256 -sign private.pem -out sha256.sig in.dat

Demonstrates how to duplicate this OpenSSL command:

openssl dgst -sha256 -sign private.pem -out sha256.sig in.dat

1. Creates a SHA256 digest of the contents of the input file
2. Signs the SHA256 digest using the private key.

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

void ChilkatSample(void)
    {
    HCkPrivateKeyW pkey;
    BOOL success;
    HCkRsaW rsa;
    HCkBinDataW bdFileData;
    HCkBinDataW bdSig;

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    pkey = CkPrivateKeyW_Create();

    // Load the private key from an PEM file:
    success = CkPrivateKeyW_LoadPemFile(pkey,L"private.pem");
    if (success != TRUE) {
        wprintf(L"%s\n",CkPrivateKeyW_lastErrorText(pkey));
        CkPrivateKeyW_Dispose(pkey);
        return;
    }

    rsa = CkRsaW_Create();

    // Import the private key into the RSA component:
    success = CkRsaW_ImportPrivateKeyObj(rsa,pkey);
    if (success != TRUE) {
        wprintf(L"%s\n",CkRsaW_lastErrorText(rsa));
        CkPrivateKeyW_Dispose(pkey);
        CkRsaW_Dispose(rsa);
        return;
    }

    // OpenSSL uses big-endian.
    CkRsaW_putLittleEndian(rsa,FALSE);

    // Load the file to be signed.
    bdFileData = CkBinDataW_Create();
    success = CkBinDataW_LoadFile(bdFileData,L"in.dat");

    bdSig = CkBinDataW_Create();
    success = CkRsaW_SignBd(rsa,bdFileData,L"sha256",bdSig);
    if (success != TRUE) {
        wprintf(L"%s\n",CkRsaW_lastErrorText(rsa));
        CkPrivateKeyW_Dispose(pkey);
        CkRsaW_Dispose(rsa);
        CkBinDataW_Dispose(bdFileData);
        CkBinDataW_Dispose(bdSig);
        return;
    }

    // Save the binary signature to a file.
    success = CkBinDataW_WriteFile(bdSig,L"signature.sig");
    if (success != TRUE) {
        wprintf(L"Failed to write signature.sig.\n");
        CkPrivateKeyW_Dispose(pkey);
        CkRsaW_Dispose(rsa);
        CkBinDataW_Dispose(bdFileData);
        CkBinDataW_Dispose(bdSig);
        return;
    }

    wprintf(L"Success.\n");


    CkPrivateKeyW_Dispose(pkey);
    CkRsaW_Dispose(rsa);
    CkBinDataW_Dispose(bdFileData);
    CkBinDataW_Dispose(bdSig);

    }