Java

Export a Public Key as PEM

Demonstrates the Chilkat PublicKey.GetPem method, which returns the public key in PEM format. The only argument selects the underlying DER representation: true prefers the traditional PKCS #1 form (RSA), false uses the SubjectPublicKeyInfo form.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: PEM is the most portable way to share a public key — the Base64 text block most tooling reads. The boolean picks the encoding: false produces the modern, algorithm-independent PUBLIC KEY (SubjectPublicKeyInfo), which is the usual choice; true produces the older RSA-specific RSA PUBLIC KEY for tools that require it. A public key is not sensitive, so the PEM can be distributed openly.

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

public class ChilkatExample {

    public static void main(String[] args) {
        // Load a public key to export.  LoadFromFile inspects the content, so it accepts DER, PEM, XML,
        // JWK, and other supported representations.
        PublicKey pubKey = new PublicKey();
        try {
            pubKey.loadFromFile("qa_data/public.pem");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Export the public key in PEM format.  The argument selects the underlying DER representation:
        // true prefers the traditional PKCS #1 form (RSA), false uses the SubjectPublicKeyInfo form.
        boolean preferPkcs1 = false;
        String pem;
        try {
            pem = pubKey.getPem(preferPkcs1);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println(pem);
    }
}