Password Protect a SQLite DB. Is it possible?

You can use the built-in encryption of the sqlite .net provider (System.Data.SQLite). See more details at http://web.archive.org/web/20070813071554/http://sqlite.phxsoftware.com/forums/t/130.aspx

To encrypt an existing unencrypted database, or to change the password of an encrypted database, open the database and then use the ChangePassword() function of SQLiteConnection:

// Opens an unencrypted database
SQLiteConnection cnn = new SQLiteConnection("Data Source=c:\\test.db3");
cnn.Open();
// Encrypts the database. The connection remains valid and usable afterwards.
cnn.ChangePassword("mypassword");

To decrypt an existing encrypted database call ChangePassword() with a NULL or "" password:

// Opens an encrypted database
SQLiteConnection cnn = new SQLiteConnection("Data Source=c:\\test.db3;Password=mypassword");
cnn.Open();
// Removes the encryption on an encrypted database.
cnn.ChangePassword(null);

To open an existing encrypted database, or to create a new encrypted database, specify a password in the ConnectionString as shown in the previous example, or call the SetPassword() function before opening a new SQLiteConnection. Passwords specified in the ConnectionString must be cleartext, but passwords supplied in the SetPassword() function may be binary byte arrays.

// Opens an encrypted database by calling SetPassword()
SQLiteConnection cnn = new SQLiteConnection("Data Source=c:\\test.db3");
cnn.SetPassword(new byte[] { 0xFF, 0xEE, 0xDD, 0x10, 0x20, 0x30 });
cnn.Open();
// The connection is now usable

By default, the ATTACH keyword will use the same encryption key as the main database when attaching another database file to an existing connection. To change this behavior, you use the KEY modifier as follows:

If you are attaching an encrypted database using a cleartext password:

// Attach to a database using a different key than the main database
SQLiteConnection cnn = new SQLiteConnection("Data Source=c:\\test.db3");
cnn.Open();
cmd = new SQLiteCommand("ATTACH DATABASE 'c:\\pwd.db3' AS [Protected] KEY 'mypassword'", cnn);
cmd.ExecuteNonQuery();

To attach an encrypted database using a binary password:

// Attach to a database encrypted with a binary key
SQLiteConnection cnn = new SQLiteConnection("Data Source=c:\\test.db3");
cnn.Open();
cmd = new SQLiteCommand("ATTACH DATABASE 'c:\\pwd.db3' AS [Protected] KEY X'FFEEDD102030'", cnn);
cmd.ExecuteNonQuery();

You can password protect a SQLite3 DB. Before doing any operations, set the password as follows.

SQLiteConnection conn = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;");
conn.SetPassword("password");
conn.Open();

then next time you can access it like

conn = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;Password=password;");
conn.Open();

This wont allow any GUI editor to view your data. Some editors can decrypt the DB if you provide the password. The algorithm used is RSA.

Later if you wish to change the password, use

conn.ChangePassword("new_password");

To reset or remove password, use

conn.ChangePassword(String.Empty);

Use SQLCipher, it's an opensource extension for SQLite that provides transparent 256-bit AES encryption of database files. http://sqlcipher.net

You can encrypt your SQLite database with the SEE addon. This way you prevent unauthorized access/modification.

Quoting SQLite documentation:

The SQLite Encryption Extension (SEE) is an enhanced version of SQLite that encrypts database files using 128-bit or 256-Bit AES to help prevent unauthorized access or modification. The entire database file is encrypted so that to an outside observer, the database file appears to contain white noise. There is nothing that identifies the file as an SQLite database.

You can find more info about this addon in this link.