Android™

Load a Public Key from Base64 DER

Demonstrates the Chilkat PublicKey.LoadBase64 method, which loads a public key from standard Base64-encoded DER. The only argument is the Base64 string; whitespace within it is permitted.

Background: A public key in DER (binary) form is often carried as Base64 text so it can travel through channels that expect a string — a config value, a JSON field, a certificate export. This loader decodes that text and inspects the DER to determine the key type and structure automatically. It is the plain-Base64 counterpart to loading a full PEM block, which additionally has the BEGIN/END armor.

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// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    boolean success = false;

    //  Demonstrates the PublicKey.LoadBase64 method, which loads a public key from standard
    //  Base64-encoded DER.  The only argument is the Base64 string (whitespace is allowed).

    CkPublicKey pubKey = new CkPublicKey();

    //  The Base64 of the DER-encoded public key.
    String keyStr = "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA...IDAQAB";

    success = pubKey.LoadBase64(keyStr);
    if (success == false) {
        Log.i(TAG, pubKey.lastErrorText());
        return;
        }

    Log.i(TAG, "Loaded a " + pubKey.keyType() + " public key.");

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}