Question

我开始使用sqlite数据库开发一个Android应用程序。过了一段时间，我实现了大部分想要的功能，我决定插入数据库加密。为了实现这一点，我将sqlcipher与cacheword结合使用来存储和管理加密密钥。

备份和恢复我的数据库我在未加密的数据库简单方法的情况下用于将mydb.db文件的副本复制到sdcard，反之亦然。使用加密，这两种方法首先完成了它们的工作而没有出现错误消息，但是在恢复之后，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();
    }
}

我的错误消息的一部分：

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)

如何使用加密数据库的副本作为备份？

使用sqlcipher_export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的问题。

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() + "';");
...

以下是错误消息：

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';'

我不知道如何解决这个问题。你能救我吗？

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，但我不确定您在哪里得到上述错误。您应该在尝试使用SQLiteDatabase类连接到数据库的位置收到上述错误。你可以在恢复后将代码发布到连接数据库的地方

备份和恢复加密数据库（sqlcipher，cacheword）？

1 个答案: