(MFC) Duplicate openssl dgst -md5 -sign myKey.pem something.txt | openssl enc -base64 -A

Demonstrates how to duplicate the creation of an RSA signature produced by this OpenSSL command:

openssl dgst -md5 -sign myKey.pem something.txt | openssl enc -base64 -A

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkPrivateKey.h>
#include <CkRsa.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    CkPrivateKey pkey;

    // Load the private key from an RSA PEM file:
    bool success = pkey.LoadPemFile("myKey.pem");

    const char *pkeyXml = 0;

    // Get the private key in XML format:
    pkeyXml = pkey.getXml();

    CkRsa rsa;

    // Import the private key into the RSA component:
    success = rsa.ImportPrivateKey(pkeyXml);
    if (success != true) {
        strOut.append(rsa.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // OpenSSL uses BigEndian byte ordering:
    rsa.put_LittleEndian(false);

    // The resulting signature will be a Base64 string:
    rsa.put_EncodingMode("base64");

    // For simplicity, we're not loading
    // the data to be signed from a file.  We are instead simply
    // using a literal string value.  
    const char *strData = "This is the text to be signed.";

    // Hash the input using MD5, and then sign the hash:
    // Other valid hash algorithm choices are "md2" and "sha-1".
    const char *base64Sig = rsa.signStringENC(strData,"md5");

    strOut.append(base64Sig);
    strOut.append("\r\n");

    strOut.append("Success!");
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }