Set a Per-Recipient JWE Header

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.SetRecipientHeader, which sets the per-recipient unprotected header for a recipient index.

// 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;

    CkJwe jwe = new CkJwe();

    //  Protected header: AES key-wrap with AES-256-GCM content encryption.
    CkJsonObject header = new CkJsonObject();
    header.UpdateString("alg","A256KW");
    header.UpdateString("enc","A256GCM");
    success = jwe.SetProtectedHeader(header);
    if (success == false) {
        Log.i(TAG, jwe.lastErrorText());
        return;
        }

    //  The 256-bit key-wrapping key (base64) for recipient index 0.  In production, obtain the key from a
    //  secure source rather than hard-coding it.
    String base64Key = "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=";
    success = jwe.SetWrappingKey(0,base64Key,"base64");
    if (success == false) {
        Log.i(TAG, jwe.lastErrorText());
        return;
        }

    //  Set the per-recipient unprotected header for recipient 0, for example a key id used to identify
    //  which key a recipient should use.
    CkJsonObject recipHeader = new CkJsonObject();
    recipHeader.UpdateString("kid","recipient-key-1");
    success = jwe.SetRecipientHeader(0,recipHeader);
    if (success == false) {
        Log.i(TAG, jwe.lastErrorText());
        return;
        }

    CkStringBuilder sbContent = new CkStringBuilder();
    sbContent.Append("This is the secret content.");
    CkStringBuilder sbJwe = new CkStringBuilder();
    success = jwe.EncryptSb(sbContent,"utf-8",sbJwe);
    if (success == false) {
        Log.i(TAG, jwe.lastErrorText());
        return;
        }

    Log.i(TAG, sbJwe.getAsString());

  }

  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."
  }
}