(MFC) RSASSA-PSS Algorithm with SHA256 Hashing

RSA encrypt a SHA256 hash with OAEP padding.

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

    CkPrivateKey privkey;

    // Load the private key object from a PEM file.
    // (To load from a PEM string, call LoadPem instead.)
    bool success = privkey.LoadPemFile("somePath/myPrivateKey.pem");
    if (success != true) {
        strOut.append(privkey.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    CkRsa rsa;
    // Use RSA-PSS by setting OaepPadding = true
    rsa.put_OaepPadding(true);
    // Use SHA256
    rsa.put_OaepHash("SHA-256");

    rsa.ImportPrivateKeyObj(privkey);

    // Generate a base64 signature.
    rsa.put_EncodingMode("base64");

    const char *sigStr = rsa.signStringENC("String to be signed","SHA-256");
    if (rsa.get_LastMethodSuccess() != true) {
        strOut.append(rsa.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    strOut.append("Signature: ");
    strOut.append(sigStr);
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }