android - 加密数据库(sqlcipher，cacheword)的备份和恢复？

Question

我开始使用 sqlite 数据库开发一个 android 应用程序。一段时间后，我想要的大部分功能都实现了，我决定插入数据库加密。为此，我结合使用了 sqlcipher 和 cacheword 来存储和管理加密 key 。

为了备份和恢复我的数据库，我在未加密数据库的情况下使用了简单的方法，将 mydb.db 文件复制到 sdcard，反之亦然。通过加密，这两种方法首先都在没有错误消息的情况下完成了他们的工作，但在恢复后，应用程序无法使用我的数据库。

备份方法:

public static void BackupDatabase() throws IOException {
    boolean success = true;
    File file = null;
    file = new File(Environment.getExternalStorageDirectory() +"/myapp");

    if(file.exists()) {
        success = true;
    }  
    else {
        success = file.mkdir();
    }

    if(success) {
        String inFileName = "/data/data/de.my.app/databases/mydb.db";
        File dbFile = new File(inFileName);
        FileInputStream fis = new FileInputStream(dbFile);

        String outFileName = Environment.getExternalStorageDirectory()+"/myapp/mydb.db.backup";
        // Open the empty db as the output stream
        OutputStream output = new FileOutputStream(outFileName);
        //transfer bytes from the inputfile to the outputfile
        byte[] buffer = new byte[1024];
        int length;
        while ((length = fis.read(buffer))>0) {
            output.write(buffer, 0, length);
        }

        output.flush();
        output.close();
        fis.close();
    }
}

恢复方法:

public static void RestoreDatabase(Context context) throws IOException {
    try {

        // Set the folder on the SDcard
        File directory = new File(Environment.getExternalStorageDirectory()+"/myapp/");
        boolean directoryB = new File(Environment.getExternalStorageDirectory()+"/myapp/", "/mydb.db.backup").exists();

        if (directoryB == true) {

            OutputStream myOutput;   
            myOutput = new FileOutputStream("/data/data/de.my.app/databases/mydb.db");

            // Set the input file stream up:

            InputStream myInputs = new FileInputStream(directory.getPath()+ "/mydb.db.backup");


            // Transfer bytes from the input file to the output file
            byte[] buffer = new byte[1024];
            int length;
            while ((length = myInputs.read(buffer))>0) {
                myOutput.write(buffer, 0, length);
            }


            // Close and clear the streams
            myOutput.flush();

            myOutput.close();

            myInputs.close();   

        }
        else {
            Toast.makeText(context, "Wiederherstellung gescheitert! Datei nicht gefunden! Ordner/Datei existiert nicht?", Toast.LENGTH_SHORT).show();
        }

    } catch (FileNotFoundException e) {
        Toast.makeText(context, "Wiederherstellung gescheitert! Datei nicht gefunden! Ordner/Datei existiert nicht?", Toast.LENGTH_LONG).show();

        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {   
        Toast.makeText(context, "Wiederherstellung gescheitert!", Toast.LENGTH_SHORT).show();


        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

部分错误信息:

10-01 22:52:58.050: I/Database(4223): sqlite returned: error code = 26, msg = file is encrypted or is not a database
10-01 22:52:58.050: E/Database(4223): CREATE TABLE android_metadata failed
10-01 22:52:58.060: E/Database(4223): Failed to setLocale() when constructing, closing the database
10-01 22:52:58.060: E/Database(4223): net.sqlcipher.database.SQLiteException: file is encrypted or is not a database
10-01 22:52:58.060: E/Database(4223):   at net.sqlcipher.database.SQLiteDatabase.native_setLocale(Native Method)
10-01 22:52:58.060: E/Database(4223):   at net.sqlcipher.database.SQLiteDatabase.setLocale(SQLiteDatabase.java:2102)
10-01 22:52:58.060: E/Database(4223):   at net.sqlcipher.database.SQLiteDatabase.<init>(SQLiteDatabase.java:1968)
10-01 22:52:58.060: E/Database(4223):   at net.sqlcipher.database.SQLiteDatabase.openDatabase(SQLiteDatabase.java:901)
10-01 22:52:58.060: E/Database(4223):   at net.sqlcipher.database.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:944)
10-01 22:52:58.060: E/Database(4223):   at net.sqlcipher.database.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:107)
10-01 22:52:58.060: E/Database(4223):   at info.guardianproject.cacheword.SQLCipherOpenHelper.getWritableDatabase(SQLCipherOpenHelper.java:53)

如何实现使用加密数据库的副本作为备份？

---

sqlcipher_export 的使用有助于备份我的数据库。但是现在我在恢复数据库方面遇到了新问题。

我尝试了以下代码:

SQLiteDatabase db = SQLiteDatabase.openOrCreateDatabase(backupFile, backuppassword, null);
db.execSQL("ATTACH DATABASE '" + dbFile + "' AS encrypted KEY '" + mCacheWord.getEncryptionKey() + "';");
...

错误信息如下:

10-30 00:56:42.845: I/Database(14407): sqlite returned: error code = 26, msg = statement aborts at 5: [ATTACH DATABASE '/data/data/.../databases/database.db' AS encrypted KEY '[B@42082da0';] file is encrypted or is not a database
10-30 00:56:42.845: E/Database(14407): Failure 26 (file is encrypted or is not a database) on 0x63bdedb0 when executing 'ATTACH DATABASE '/data/data/.../databases/database.db' AS encrypted KEY '[B@42082da0';'

我不知道如何解决这个问题。你能帮帮我吗？

Answer 1

您应该使用 sql_export 函数来备份、解密和加密您的数据库。对于上述错误，解决方案是在标志中使用 NO_LOCALIZED_COLLATORS，但我不确定您从哪里得到上述错误。您应该在尝试使用 SQLiteDatabase 类连接到数据库的地方遇到上述错误。你能在恢复后发布连接到数据库的代码吗