Verify a Password against an Argon2 Hash

Demonstrates Crypt2.Argon2VerifyPassword, which verifies a password against a PHC-format Argon2 hash string. The cost parameters are read from the hash string, so none need to be supplied.

// 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";

    //  A PHC-format Argon2 hash string previously produced by Argon2HashPassword.  All cost options
    //  (variant, version, memory cost, iterations, parallelism, salt, hash length) are read from this
    //  string, so none need to be supplied.
    String phcHash = "$argon2id$v=19$m=65536,t=3,p=1$c29tZXJhbmRvbXNhbHQ$3fJ7v1qKcVJ0lHqXjBQZ8mYm3sNTfSPRt0bqDl9kEyM";

    //  Verify the password.  Pass an empty options string when no secret (pepper) or ad was used.
    //  The method returns one of three values:  1 = the password matched, 0 = it did not match, and
    //  -1 = the verification could not be performed (the hash string was invalid or unusable).
    //  Always test for a match with == 1.
    int verifyResult = crypt.Argon2VerifyPassword(password,"",phcHash);
    if (verifyResult == 1) {
        Log.i(TAG, "The password is verified.");
        }
    else {
        if (verifyResult == 0) {
            Log.i(TAG, "The password does not match.");
            }
        else {
            Log.i(TAG, "The verification could not be performed: " + crypt.lastErrorText());
            }

        }


  }

  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."
  }
}