(Android™) Encrypting and Decrypting Content

Demonstrates how to encrypt and decrypt the content of an XML node using 128-bit CBC AES encryption.

The input XML, available at http://www.chilkatsoft.com/data/fox.xml, is this:

<root>
    <fox1>The quick brown fox jumps over the lazy dog</fox1>
    <fox2>The quick brown fox jumps over the lazy dog
        <child1>ABC</child1>
        <child2>XYZ</child2>
    </fox2>
</root>

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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);

    CkXml xml = new CkXml();

    boolean success;
    // The sample input XML is available at http://www.chilkatsoft.com/data/fox.xml
    success = xml.LoadXmlFile("fox.xml");
    if (success != true) {
        Log.i(TAG, xml.lastErrorText());
        return;
        }

    // Navigate to the "fox1" node, which is the 1st child:
    success = xml.FirstChild2();

    // Encrypt the content:
    success = xml.EncryptContent("myPassword");

    // Navigate back to the root:
    xml.GetRoot2();

    // Examine the new XML document:
    Log.i(TAG, xml.getXml());

    // This is the XML w/ the encrypted content:
    // <root>
    //     <fox1>1hTtf7XmO+78H+OIr5eWHIuXxP78KPeYrZbsD0HX4negO9ZRqYMBY4s46sPNp+Q+
    //     </fox1>
    //     <fox2>The quick brown fox jumps over the lazy dog
    //         <child1>ABC</child1>
    //         <child2>XYZ</child2>
    //     </fox2>
    // </root>

    // Now decrypt and show that the original content was restored:
    success = xml.FirstChild2();
    success = xml.DecryptContent("myPassword");
    xml.GetRoot2();
    Log.i(TAG, xml.getXml());

    // Now encrypt the content of the "fox2" node.
    // First navigate to the "fox2" child.
    success = xml.FindChild2("fox2");
    success = xml.EncryptContent("myPassword");
    xml.GetRoot2();
    Log.i(TAG, xml.getXml());

    // This is the XML w/ the "fox2" encrypted content:

    // <root>
    //     <fox1>The quick brown fox jumps over the lazy dog</fox1>
    //     <fox2>1hTtf7XmO+78H+OIr5eWHIuXxP78KPeYrZbsD0HX4negO9ZRqYMBY4s46sPNp+Q+
    // 
    //         <child1>ABC</child1>
    //         <child2>XYZ</child2>
    //     </fox2>
    // </root>

    // Notice that the *content* of the node is encrypted.  The child nodes are NOT encrypted.
    // This is intentional.  To encrypt the content + the subtrees rooted at a given node, 
    // one would call ZipTree to transform the content and subtrees
    // to Base64-encoded compressed content, and then call
    // EncryptContent to encrypt.

    // Finally, decrypt the "fox2" content:
    success = xml.FindChild2("fox2");
    success = xml.DecryptContent("myPassword");
    xml.GetRoot2();
    Log.i(TAG, xml.getXml());

  }

  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."
  }
}