在Android中使用SQLCipher加密/解密现有数据库

我使用下面的代码对我能够加密的数据库进行加密和解密，但当我尝试解密时，我得到了下面的异常。我引用了这段代码，但仍然面临同样的问题

例外情况：

sqlite returned: error code = 26, msg = file is encrypted or is not a database
CREATE TABLE android_metadata failed
Failed to setLocale() when constructing, closing the database
net.sqlcipher.database.SQLiteException: file is encrypted or is not a database

private static void ConvertNormalToSQLCipheredDB(Context context,
 String startingFileName, String endingFileName, String filePassword)
 throws IOException {
  File mStartingFile = context.getDatabasePath(startingFileName);
  if (!mStartingFile.exists()) {
   return;
  }
  File mEndingFile = context.getDatabasePath(endingFileName);
  mEndingFile.delete();
  SQLiteDatabase database = null;
  try {
   database = SQLiteDatabase.openOrCreateDatabase(MainApp.mainDBPath,
   "", null);
   database.rawExecSQL(String.format(
   "ATTACH DATABASE '%s' AS encrypted KEY '%s'",
   mEndingFile.getAbsolutePath(), filePassword));
   database.rawExecSQL("select sqlcipher_export('encrypted')");
   database.rawExecSQL("DETACH DATABASE encrypted");
   database.close();
  } catch (Exception e) {
   e.printStackTrace();
  } finally {
   if (database.isOpen())
    database.close();
   mStartingFile.delete();
  }
 }

private void decryptDatabase() {
  File unencryptedFile = getDatabasePath(PhoneNumbersDatabase.DATABASE_NAME);
  unencryptedFile.delete();
  File databaseFile = getDatabasePath("encrypt.db");
  SQLiteDatabaseHook hook = new SQLiteDatabaseHook() {
   public void preKey(SQLiteDatabase sqLiteDatabase) {
    sqLiteDatabase
      .rawExecSQL("PRAGMA cipher_default_use_hmac = off;");
   }

   public void postKey(SQLiteDatabase sqLiteDatabase) {
   }
  };
  SQLiteDatabase database = SQLiteDatabase.openOrCreateDatabase(
    databaseFile, "test123", null, hook); // Exception 
  if (database.isOpen()) {
   database.rawExecSQL(String.format(
     "ATTACH DATABASE '%s' as plaintext KEY '';",
     unencryptedFile.getAbsolutePath()));
   database.rawExecSQL("SELECT sqlcipher_export('plaintext');");
   database.rawExecSQL("DETACH DATABASE plaintext;");
   android.database.sqlite.SQLiteDatabase sqlDB = android.database.sqlite.SQLiteDatabase
     .openOrCreateDatabase(unencryptedFile, null);
   sqlDB.close();
   database.close();
  }

  databaseFile.delete();
 }

加密：

sqlite returned: error code = 26, msg = file is encrypted or is not a database
CREATE TABLE android_metadata failed
Failed to setLocale() when constructing, closing the database
net.sqlcipher.database.SQLiteException: file is encrypted or is not a database

private static void ConvertNormalToSQLCipheredDB(Context context,
 String startingFileName, String endingFileName, String filePassword)
 throws IOException {
  File mStartingFile = context.getDatabasePath(startingFileName);
  if (!mStartingFile.exists()) {
   return;
  }
  File mEndingFile = context.getDatabasePath(endingFileName);
  mEndingFile.delete();
  SQLiteDatabase database = null;
  try {
   database = SQLiteDatabase.openOrCreateDatabase(MainApp.mainDBPath,
   "", null);
   database.rawExecSQL(String.format(
   "ATTACH DATABASE '%s' AS encrypted KEY '%s'",
   mEndingFile.getAbsolutePath(), filePassword));
   database.rawExecSQL("select sqlcipher_export('encrypted')");
   database.rawExecSQL("DETACH DATABASE encrypted");
   database.close();
  } catch (Exception e) {
   e.printStackTrace();
  } finally {
   if (database.isOpen())
    database.close();
   mStartingFile.delete();
  }
 }

private void decryptDatabase() {
  File unencryptedFile = getDatabasePath(PhoneNumbersDatabase.DATABASE_NAME);
  unencryptedFile.delete();
  File databaseFile = getDatabasePath("encrypt.db");
  SQLiteDatabaseHook hook = new SQLiteDatabaseHook() {
   public void preKey(SQLiteDatabase sqLiteDatabase) {
    sqLiteDatabase
      .rawExecSQL("PRAGMA cipher_default_use_hmac = off;");
   }

   public void postKey(SQLiteDatabase sqLiteDatabase) {
   }
  };
  SQLiteDatabase database = SQLiteDatabase.openOrCreateDatabase(
    databaseFile, "test123", null, hook); // Exception 
  if (database.isOpen()) {
   database.rawExecSQL(String.format(
     "ATTACH DATABASE '%s' as plaintext KEY '';",
     unencryptedFile.getAbsolutePath()));
   database.rawExecSQL("SELECT sqlcipher_export('plaintext');");
   database.rawExecSQL("DETACH DATABASE plaintext;");
   android.database.sqlite.SQLiteDatabase sqlDB = android.database.sqlite.SQLiteDatabase
     .openOrCreateDatabase(unencryptedFile, null);
   sqlDB.close();
   database.close();
  }

  databaseFile.delete();
 }

解密：

sqlite returned: error code = 26, msg = file is encrypted or is not a database
CREATE TABLE android_metadata failed
Failed to setLocale() when constructing, closing the database
net.sqlcipher.database.SQLiteException: file is encrypted or is not a database

private static void ConvertNormalToSQLCipheredDB(Context context,
 String startingFileName, String endingFileName, String filePassword)
 throws IOException {
  File mStartingFile = context.getDatabasePath(startingFileName);
  if (!mStartingFile.exists()) {
   return;
  }
  File mEndingFile = context.getDatabasePath(endingFileName);
  mEndingFile.delete();
  SQLiteDatabase database = null;
  try {
   database = SQLiteDatabase.openOrCreateDatabase(MainApp.mainDBPath,
   "", null);
   database.rawExecSQL(String.format(
   "ATTACH DATABASE '%s' AS encrypted KEY '%s'",
   mEndingFile.getAbsolutePath(), filePassword));
   database.rawExecSQL("select sqlcipher_export('encrypted')");
   database.rawExecSQL("DETACH DATABASE encrypted");
   database.close();
  } catch (Exception e) {
   e.printStackTrace();
  } finally {
   if (database.isOpen())
    database.close();
   mStartingFile.delete();
  }
 }

private void decryptDatabase() {
  File unencryptedFile = getDatabasePath(PhoneNumbersDatabase.DATABASE_NAME);
  unencryptedFile.delete();
  File databaseFile = getDatabasePath("encrypt.db");
  SQLiteDatabaseHook hook = new SQLiteDatabaseHook() {
   public void preKey(SQLiteDatabase sqLiteDatabase) {
    sqLiteDatabase
      .rawExecSQL("PRAGMA cipher_default_use_hmac = off;");
   }

   public void postKey(SQLiteDatabase sqLiteDatabase) {
   }
  };
  SQLiteDatabase database = SQLiteDatabase.openOrCreateDatabase(
    databaseFile, "test123", null, hook); // Exception 
  if (database.isOpen()) {
   database.rawExecSQL(String.format(
     "ATTACH DATABASE '%s' as plaintext KEY '';",
     unencryptedFile.getAbsolutePath()));
   database.rawExecSQL("SELECT sqlcipher_export('plaintext');");
   database.rawExecSQL("DETACH DATABASE plaintext;");
   android.database.sqlite.SQLiteDatabase sqlDB = android.database.sqlite.SQLiteDatabase
     .openOrCreateDatabase(unencryptedFile, null);
   sqlDB.close();
   database.close();
  }

  databaseFile.delete();
 }

---

尝试解密数据库时，不需要在

preKey

事件中将

cipher\u default\u use\u hmac

设置为

off

。加密数据库时不会禁用它，因此数据库的每个页面都包含HMAC。尝试从解密函数中删除

SQLiteDatabaseHook

。另外，考虑加入这些类型的讨论。

谢谢你回复Nick……不知怎的，我能找出答案……我会接受这个答案来解释。看看这些样本。这些都是不言自明的：当我使用像您这样的加密方法时，我会遇到一个异常，即数据库被锁定！你能帮我吗？