Android™

Manually Duplicate SetSecretKeyViaPassword

Demonstrates how to duplicate the password string to binary secret key computation of SetSecretKeyViaPassword.

This is a cryptographically weak way of generating a secret key from a password. The SetSecretKeyViaPassword method is deprecated and should not be used.

Android™

// 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);

    //  This example assumes the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    CkCrypt2 crypt = new CkCrypt2();

    //  The password string is transformed to a binary secret key by computing the 
    //  MD5 digest (of the utf-8 password) to obtain 16 bytes.  
    //  If the KeyLength is greater than 16 bytes, then the MD5 digest of the Base64 encoding 
    //  of the utf-8 password is added.  A max of 32 bytes of key material is generated, and 
    //  this is truncated to the actual KeyLength required.

    crypt.put_CryptAlgorithm("aes");
    crypt.put_KeyLength(256);

    String password = "this is my password";
    crypt.SetSecretKeyViaPassword(password);

    //  Examine the resulting SecretKey in hex:
    Log.i(TAG, "Computed Secret Key = " + crypt.getEncodedKey("hex"));

    //  Now perform the same computation manually:
    CkStringBuilder sb = new CkStringBuilder();

    crypt.put_HashAlgorithm("md5");
    crypt.put_Charset("utf-8");
    crypt.put_EncodingMode("hex");
    sb.Append(crypt.hashStringENC(password));

    String passwordBase64 = crypt.encodeString(password,"utf-8","base64");
    sb.Append(crypt.hashStringENC(passwordBase64));

    Log.i(TAG, "Manually Computed = " + sb.getAsString());

    //  The output is:
    //  Computed Secret Key = 210D53992DFF432EC1B1A9698AF9DA16C7E90518F90E24828F78EC9E0A413B36
    //  Manually Computed = 210D53992DFF432EC1B1A9698AF9DA16C7E90518F90E24828F78EC9E0A413B36

  }

  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."
  }
}