備份和還原加密數據庫（sqlcipher，cacheword）？

Question

我開始使用sqlite數據庫開發一個android應用程序。 一段時間后，我所需的大多數功能都實現了，我決定插入數據庫加密。 為此，我將sqlcipher與cacheword結合使用來存儲和管理加密密鑰。

為了備份和還原數據庫，在未加密數據庫的情況下，我使用了簡單的方法將mydb.db文件的副本復制到sdcard，反之亦然。 進行加密后，這兩種方法都首先完成了工作，而沒有出現錯誤消息，但是還原后，該應用程序無法使用我的數據庫。

備份方法：

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();
    }
}

還原方法：

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();
    }
}

我的部分錯誤消息：

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)

如何實現將加密數據庫的副本用作備份？

---

sqlcipher_export的使用有助於對我的數據庫進行備份。 但是現在我在數據庫還原方面遇到了新問題。

我嘗試了以下代碼：

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

這是錯誤消息：

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';'

我不知道如何解決這個問題。 你能幫助我嗎？

Answer 1

您應該使用sql_export函數備份，解密和加密數據庫。 對於上述錯誤，解決方案是在標志中使用NO_LOCALIZED_COLLATORS，但我不確定您在哪里確切地收到上述錯誤。 您應該在嘗試使用SQLiteDatabase類連接到數據庫的地方收到上述錯誤。 您可以在還原后將代碼發布到您連接到數據庫的位置嗎