Converting sqlite to encrypted database:

Question

I\'ve an existing sqlite database in my application. It running successfully. Now i need to encrypt the database using sqlcipher. My problem is at the time of converting sqlite

Answer 1

Thanks, it works great. I added this code to encrypt, decrypt and change the password.

@Override
public synchronized SQLiteDatabase getWritableDatabase(String password) {
    SQLiteDatabase sqLiteDatabase;
    try{
        sqLiteDatabase = super.getWritableDatabase(password);
    }catch(Exception e){
        try {
            encrypt(context,DATABASE_NAME,PWOLD,PWNEW);
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        sqLiteDatabase = super.getWritableDatabase(password);
    }
    return sqLiteDatabase;
}

@Override
public synchronized SQLiteDatabase getReadableDatabase(String password) {
    SQLiteDatabase sqLiteDatabase;
    try{
        sqLiteDatabase = super.getReadableDatabase(password);
    }catch(Exception e){
        try {
            encrypt(context, DATABASE_NAME, PWOLD, PWNEW);
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        sqLiteDatabase = super.getReadableDatabase(password);
    }
    return sqLiteDatabase;
}

public static void encrypt(Context context, String dbName,
                           String oldPass, String newPass) throws IOException {
    if(!newPass.isEmpty()) Log.d(TAG,"Encrypt DB...");
    else Log.d(TAG,"Decrypt DB...");

    File originalFile=context.getDatabasePath(dbName);

    if (originalFile.exists()) {
        File newFile = File.createTempFile("sqlcipherutils", "tmp",
                        context.getCacheDir());
        SQLiteDatabase db = SQLiteDatabase.openDatabase(originalFile.getAbsolutePath(),
                oldPass, null,
                SQLiteDatabase.OPEN_READWRITE);

        db.rawExecSQL(String.format("ATTACH DATABASE '%s' AS encrypted KEY '%s';",
                newFile.getAbsolutePath(), newPass));
        db.rawExecSQL("SELECT sqlcipher_export('encrypted')");
        db.rawExecSQL("DETACH DATABASE encrypted;");

        int version=db.getVersion();

        db.close();

        db = SQLiteDatabase.openDatabase(newFile.getAbsolutePath(),
                newPass, null,
                SQLiteDatabase.OPEN_READWRITE);
        db.setVersion(version);
        db.close();

        originalFile.delete();
        newFile.renameTo(originalFile);
    }
}

Answer 2

You are using databaseFile twice. Your openOrCreateDatabase() should be called for old_sqliteFile, not databaseFile.

Here is a method that will replace an unencrypted database file with an encrypted replacement:

  public static void encrypt(Context ctxt, String dbName,
                             String passphrase) throws IOException {
    File originalFile=ctxt.getDatabasePath(dbName);

    if (originalFile.exists()) {
      File newFile=
          File.createTempFile("sqlcipherutils", "tmp",
                              ctxt.getCacheDir());
      SQLiteDatabase db=
          SQLiteDatabase.openDatabase(originalFile.getAbsolutePath(),
                                      "", null,
                                      SQLiteDatabase.OPEN_READWRITE);

      db.rawExecSQL(String.format("ATTACH DATABASE '%s' AS encrypted KEY '%s';",
                                  newFile.getAbsolutePath(), passphrase));
      db.rawExecSQL("SELECT sqlcipher_export('encrypted')");
      db.rawExecSQL("DETACH DATABASE encrypted;");

      int version=db.getVersion();

      db.close();

      db=
          SQLiteDatabase.openDatabase(newFile.getAbsolutePath(),
                                      passphrase, null,
                                      SQLiteDatabase.OPEN_READWRITE);
      db.setVersion(version);
      db.close();

      originalFile.delete();
      newFile.renameTo(originalFile);
    }
  }