open-keychain/org_apg/src/org/thialfihar/android/apg/passphrase/AskForPassphrase.java

/*
 * Copyright (C) 2010 Thialfihar <thi@thialfihar.org>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.thialfihar.android.apg.passphrase;

import org.spongycastle.jce.provider.BouncyCastleProvider;
import org.spongycastle.openpgp.PGPException;
import org.spongycastle.openpgp.PGPPrivateKey;
import org.spongycastle.openpgp.PGPSecretKey;
import org.thialfihar.android.apg.Apg;
import org.thialfihar.android.apg.Id;
import org.thialfihar.android.apg.R;

import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class AskForPassphrase {
    public static interface PassPhraseCallbackInterface {
        void passPhraseCallback(long keyId, String passPhrase);
    }

    public static Dialog createDialog(Activity context, long secretKeyId,
            PassPhraseCallbackInterface callback) {
        AlertDialog.Builder alert = new AlertDialog.Builder(context);

        alert.setTitle(R.string.title_authentication);

        final PGPSecretKey secretKey;
        final Activity activity = context;

        if (secretKeyId == Id.key.symmetric || secretKeyId == Id.key.none) {
            secretKey = null;
            alert.setMessage(context.getString(R.string.passPhraseForSymmetricEncryption));
        } else {
            secretKey = Apg.getMasterKey(Apg.getSecretKeyRing(secretKeyId));
            if (secretKey == null) {
                alert.setTitle(R.string.title_keyNotFound);
                alert.setMessage(context.getString(R.string.keyNotFound, secretKeyId));
                alert.setPositiveButton(android.R.string.ok, new OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        activity.removeDialog(Id.dialog.pass_phrase);
                    }
                });
                alert.setCancelable(false);
                return alert.create();
            }
            String userId = Apg.getMainUserIdSafe(context, secretKey);
            alert.setMessage(context.getString(R.string.passPhraseFor, userId));
        }

        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View view = inflater.inflate(R.layout.passphrase, null);
        final EditText input = (EditText) view.findViewById(R.id.passphrase_passphrase);

        final TextView labelNotUsed = (TextView) view
                .findViewById(R.id.passphrase_label_passphrase_again);
        labelNotUsed.setVisibility(View.GONE);
        final EditText inputNotUsed = (EditText) view
                .findViewById(R.id.passphrase_passphrase_again);
        inputNotUsed.setVisibility(View.GONE);

        alert.setView(view);

        final PassPhraseCallbackInterface cb = callback;
        alert.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                activity.removeDialog(Id.dialog.pass_phrase);
                String passPhrase = input.getText().toString();
                long keyId;
                if (secretKey != null) {
                    try {
                        PGPPrivateKey testKey = secretKey.extractPrivateKey(
                                passPhrase.toCharArray(), new BouncyCastleProvider());
                        if (testKey == null) {
                            Toast.makeText(activity, R.string.error_couldNotExtractPrivateKey,
                                    Toast.LENGTH_SHORT).show();
                            return;
                        }
                    } catch (PGPException e) {
                        Toast.makeText(activity, R.string.wrongPassPhrase, Toast.LENGTH_SHORT)
                                .show();
                        return;
                    }
                    keyId = secretKey.getKeyID();
                } else {
                    keyId = Id.key.symmetric;
                }
                
                // cache again
                Apg.setCachedPassPhrase(keyId, passPhrase);
                // return by callback
                cb.passPhraseCallback(keyId, passPhrase);
            }
        });

        alert.setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                activity.removeDialog(Id.dialog.pass_phrase);
            }
        });

        // check if the key has no passphrase
        if (secretKey != null) {
            try {
                Log.d("APG", "check if key has no passphrase...");
                PGPPrivateKey testKey = secretKey.extractPrivateKey("".toCharArray(),
                        new BouncyCastleProvider());
                if (testKey != null) {
                    Log.d("APG", "Key has no passphrase!");

                    // cache null
                    Apg.setCachedPassPhrase(secretKey.getKeyID(), null);
                    // return by callback
                    cb.passPhraseCallback(secretKey.getKeyID(), null);

                    return null;
                }
            } catch (PGPException e) {

            }
        }
        return alert.create();
    }
}