(MFC) Get an EC Key in Raw Hex Format

Demonstrates how to get the private and public key parts of an EC (ECDSA) key in lowercase hex formmat.

Note: This example requires Chilkat v9.5.0.83 or greater.

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

See Also: Using MFC CString in Chilkat

#include <CkPrivateKey.h>
#include <CkStringBuilder.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    // Load an EC key from some format..
    CkPrivateKey privKey;

    // This loads an ECDSA key from an unencrypted PEM file (no password required).
    bool success = privKey.LoadAnyFormatFile("qa_data/ecc/openssl_ecc_privKey.pem","");
    if (success == false) {
        strOut.append(privKey.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // The key type should be "ecc" to indicate an EC key.
    strOut.append("key type = ");
    strOut.append(privKey.keyType());
    strOut.append("\r\n");

    // What is the size of the private key in bits?
    strOut.append("size in bits = ");
    strOut.appendInt(privKey.get_BitLength());
    strOut.append("\r\n");

    // Get the private and public EC key parts in raw hex format:
    CkStringBuilder sbPubKeyHex;
    const char *privKeyHex = privKey.getRawHex(sbPubKeyHex);

    // If the private key size in bits is 256, then we should have a 32-byte key (a 64 character hex string).
    strOut.append("private key = ");
    strOut.append(privKeyHex);
    strOut.append("\r\n");

    // The public key is composed of the "x" and "y" parts, and is composed like this:  04||HEX(x)||HEX(y)
    strOut.append("public key = ");
    strOut.append(sbPubKeyHex.getAsString());
    strOut.append("\r\n");

    // Sample output:
    // key type = ecc
    // size in bits = 256
    // private key = ced36f2ba3332be439f79143d69937fc52494cd38e45243c3ea05db183919f1b
    // public key = 045b4edcd501831740895f5907feabb71587076a6314d9d5141f9f8c33a478b8ce08b8dfd2a091eb6355803d7e729876c790bc0b176f2015f3bb103813753f676a


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }