(MFC) Get ECC Public Key from ECC Private Key

Demonstrates how to get an ECC public key from an ECC private key.

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

See Also: Using MFC CString in Chilkat

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

void ChilkatSample(void)
    {
    CkString strOut;

    // We have an ECC private key...
    // The contents of the private key PEM file look like this:

    // 	-----BEGIN PRIVATE KEY-----
    // 	MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQg3J8q/24D1sEKGdP9
    // 	72MGYElLGpw/a56Y3t6pfON3uhShRANCAATlSmoizyhAwoYZAOuFBATl07/1RR54
    // 	a1Dzfm16grxJe666AGKR+bSs24hk7TEpaeCTvT8YOOM3l+xKFg7zq6Q9
    // 	-----END PRIVATE KEY-----

    CkPrivateKey privKey;
    bool success = privKey.LoadPemFile("qa_data/ecc/secp256r1-key-pkcs8.pem");
    if (success != true) {
        strOut.append(privKey.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Get the public key.
    CkPublicKey *pubKey = privKey.GetPublicKey();
    if (privKey.get_LastMethodSuccess() != true) {
        strOut.append(privKey.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Save the public key to a PEM file.
    success = pubKey->SavePemFile(false,"qa_data/ecc/secp256r1-pubkey.pem");
    if (success != true) {
        strOut.append(pubKey->lastErrorText());
        strOut.append("\r\n");
        delete pubKey;
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // The contents of the ECC public key PEM file look like this:

    // 	-----BEGIN PUBLIC KEY-----
    // 	MIIBSzCCAQMGByqGSM49AgEwgfcCAQEwLAYHKoZIzj0BAQIhAP////8AAAABAAAA
    // 	AAAAAAAAAAAA////////////////MFsEIP////8AAAABAAAAAAAAAAAAAAAA////
    // 	///////////8BCBaxjXYqjqT57PrvVV2mIa8ZR0GsMxTsPY7zjw+J9JgSwMVAMSd
    // 	NgiG5wSTamZ44ROdJreBn36QBEEEaxfR8uEsQkf4vOblY6RA8ncDfYEt6zOg9KE5
    // 	RdiYwpZP40Li/hp/m47n60p8D54WK84zV2sxXs7LtkBoN79R9QIhAP////8AAAAA
    // 	//////////+85vqtpxeehPO5ysL8YyVRAgEBA0IABOVKaiLPKEDChhkA64UEBOXT
    // 	v/VFHnhrUPN+bXqCvEl7rroAYpH5tKzbiGTtMSlp4JO9Pxg44zeX7EoWDvOrpD0=
    // 	-----END PUBLIC KEY-----

    delete pubKey;
    strOut.append("Success.");
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }