Java Requires Chilkat v11.0.0+

Convert RSA Private Key to Public Key

See more RSA Examples

Demonstrates how to get a public RSA key from a private RSA key. Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.PrivateKey;
import com.chilkatsoft.chilkat2.PublicKey;

public class ChilkatExample {

    public static void main(String[] args) {
        PrivateKey privKey = new PrivateKey();

        // Step 1: Load the private key from a source.
        // (Chilkat can load private keys from all types of formats, and from in-memory bytes or encoded strings.
        // see the online reference documentation for more options.)
        try {
            privKey.loadPemFile("qa_data/pem/VP_Private.pem");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Step 2: Get the public key object from the private key object.
        PublicKey pubKey = new PublicKey();
        privKey.toPublicKey(pubKey);

        // Step 3: Save the public key in a desired format.
        // (Chilkat can load or save public and private keys in many different formats.  See
        // the online reference documentation for more options.)

        // Saves to a PKCS8 PEM file.
        boolean bPreferPkcs1 = false;
        try {
            pubKey.savePemFile(bPreferPkcs1, "qa_data/pem/VP_Public.pem");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("Extracted and saved public key from private key.");
    }
}