Today, the passing files through Internet is NOT safe, even through e-mail. The usual solution is to encrypt the file and send it as encrypted. But, not every encryption is good for the job. The ideal is to create an encryption that is easy to follow, but hard to decrypt. BFC Crypter DLL Library enables about 160000 different encryption dictionaries, based on one single method. The hacker might get the encrypted data, but it will take him/her all his/her life to decrypt it back, even when using a computer. This DLL can be added to the development of every Windows application. This DLL enables a secure file input/output system, including password-protection support. The idea is to modify the file's encryption keys every time it is written. The best example is the use of binary data files that hold very important information for the program, but each time the file is re-written, the secret-keys change. Even when the written data is not changed, the encrypted file itself changes. From the programmer's point of view, he/she uses the file system functions of the DLL instead the regular ones. Another useful features are en/de-crypting entire files (with callback support for Visual C++ only) and en/de-crypting entire buffers.