Functionality
This is encryption tool you longed for! Not another of those "How to use CryptoAPI" code pieces but a ready-to-use program to password-encrypt your sensitive files. Simply create a .tyt file by choosing New > Encrypted Text File from the explorer's context menu Then double-click it, enter your data and save it encrypted with or without password. When you double-click an existing .tyt file the content is decrypted and shown in the edit field.
Of course, Windows 2000 provides a built-in encryption facility. But this lacks of the following:

• Doesn't work for files in network folders which are taken offline
• Doesn't allow to involve a password. Without password-protection a third person may gain access to your files while your computer is not locked.

CryptFile provides these functions and has a easy-to-use user interface.

Background
The program uses Windows API functions CryptProtectData and CryptUnprotectData which are part of the CryptoAPI. For more details see here and here. There functions perform a user-specific encryption/decryption. I.e., you may decrypt your information on any machine in the network as long as you are logged on with the same user credentials as during encryption time.

Prerequisites
The program requires Windows 2000 because the Windows API functions CryptProtectData and CryptUnprotectData are only available there.  

Download & Installation
Please read these terms and conditions carefully before using this software. Use of this software indicates you accept these terms.

Download the ZIP file and extract CryptFile.exe from it. Additionally you need the VB6 Runtime to be installed. If you don't have it yet you can get it from here . Run the program once from within Windows Explorer. This creates some registry entries associating the extension .tyt with the program. You can remove these registry entries by invoking the program with the command line parameter /U.

Usage
CryptFile.exe is to some extend similar to Notepad. CryptFile.exe is associated with .tyt files like Notepad is with .txt files. Double-clicking a .tyt file automatically opens and decrypts the file and allows to edit the content. You can save the content in three different variants. 

• Without encryption
• Encrypted without password
• Encrypted with password. When you open the file, CryptFile asks for the password again. The password is kept in local storage as short as possible.

How it works
See VB source code 

Known issues
If you have another application installed that already registered the file extension .tyt, the self registration of CryptFile.exe doesn't work. I never heared of such an application. In this case you can open an encrypted file by first running CryptFile and choosing File > Open from the menu.

Revisions

• 19-Aug-01: Initially submitted