(MFC) Ed25519ph Sign and Verify

Demonstrates how to create an Ed25519ph signature, and then to verify it.

Note: This example requires Chilkat v9.5.0.91 or greater.

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

See Also: Using MFC CString in Chilkat

#include <CkPrivateKey.h>
#include <CkBinData.h>
#include <CkEdDSA.h>
#include <CkPublicKey.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    // Use the following test vector from https://www.rfc-editor.org/rfc/rfc8032#page-30

    //    -----TEST abc
    // 
    //    ALGORITHM:
    //    Ed25519ph
    // 
    //    SECRET KEY:
    //    833fe62409237b9d62ec77587520911e
    //    9a759cec1d19755b7da901b96dca3d42
    // 
    //    PUBLIC KEY:
    //    ec172b93ad5e563bf4932c70e1245034
    //    c35467ef2efd4d64ebf819683467e2bf
    // 
    //    MESSAGE (length 3 bytes):
    //    616263
    // 
    //    SIGNATURE:
    //    98a70222f0b8121aa9d30f813d683f80
    //    9e462b469c7ff87639499bb94e6dae41
    //    31f85042463c2a355a2003d062adf5aa
    //    a10b8c61e636062aaad11c2a26083406

    const char *privKeyHex = "833fe62409237b9d62ec77587520911e9a759cec1d19755b7da901b96dca3d42";
    const char *pubKeyHex = "ec172b93ad5e563bf4932c70e1245034c35467ef2efd4d64ebf819683467e2bf";

    CkPrivateKey privKey;
    bool success = privKey.LoadEd25519(privKeyHex,pubKeyHex);
    if (success == false) {
        strOut.append(privKey.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // The data to be signed...
    CkBinData bd;
    bd.AppendEncoded("616263","hex");

    CkEdDSA eddsa;
    // Indicate we want the Ed25519ph instance.
    eddsa.put_Algorithm("Ed25519ph");

    const char *hexSig = eddsa.signBdENC(bd,"hexlower",privKey);

    strOut.append("signature = ");
    strOut.append(hexSig);
    strOut.append("\r\n");

    // The expected output is: 98a70222f0b8121aa9d30f813d683f80....

    // Verify the signature..
    CkPublicKey pubKey;
    success = pubKey.LoadEd25519(pubKeyHex);
    if (success == false) {
        strOut.append(pubKey.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    bool bVerified = eddsa.VerifyBdENC(bd,hexSig,"hexlower",pubKey);
    if (bVerified == false) {
        strOut.append(eddsa.lastErrorText());
        strOut.append("\r\n");
        strOut.append("Failed to verify the signature.");
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    strOut.append("The Ed25519ph signature is verified!");
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }