Hash a Password with Argon2 (Tuned Options)

Demonstrates Crypt2.Argon2HashPassword with explicit options: the cost parameters, saltLen (how many random salt bytes to generate when no salt is given), and an optional secret (pepper).

// 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);

    CkCrypt2 crypt = new CkCrypt2();

    //  The password should come from a secure source rather than being hard-coded.
    String password = "correct horse battery staple";

    //  The Argon2 options are the same members as Argon2DeriveKey, except the salt is optional for
    //  hashing.  When no "salt" is given, a random salt is generated; "saltLen" (default 16, range 8..1024)
    //  sets how many random bytes to use.
    CkJsonObject json = new CkJsonObject();
    json.UpdateString("variant","argon2id");
    json.UpdateInt("memoryCostKb",131072);
    json.UpdateInt("iterations",4);
    json.UpdateInt("parallelism",2);
    json.UpdateInt("saltLen",16);

    //  A secret (pepper) and/or ad may be used, but neither is stored in the returned PHC string.  The
    //  same values must be supplied to Argon2VerifyPassword for the password to verify.
    json.UpdateString("secret","application-wide-pepper");
    json.UpdateString("secretEncoding","utf-8");

    String phcHash = crypt.argon2HashPassword(password,json.emit());
    if (crypt.get_LastMethodSuccess() == false) {
        Log.i(TAG, crypt.lastErrorText());
        return;
        }

    Log.i(TAG, phcHash);

  }

  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."
  }
}