Advanced Encryption Package 2005 Professional
AEP2005 PRO's most noteworthy feature may be its flexibility and military grade encryption: program includes 17 encryption algorithms (Rijndael, TWOFISH, BLOWISH, CAST, MARS, TEA, etc) to encrypt your files. It also includes file shredder. RSA supp.
Mp-Crypt
Lock your mouse and PC.
CryptIt
This file encrypter is capable of using either a string or a file for the code. When using a file the encryption code can be up to 4GB. (Virtually unbreakable by any computer.) Descriptions can be stored within the encrypted file.
OpenSSL
Open SSL 0.9.7c lets applications use Secure Sockets Layer (v2/v3), Transport Layer Security (v1), and a general-purpose cryptography library, for data integrity, authenticity, and privacy security features. Perl or Cygwin needed for Win32 compile.
ASPshield
ASPshield is an ISAPI filter, protecting your code from being viewed or stolen. It protects both ASP and ASP.NET based scripts and makes client-side HTML difficult to read. ASPshield allows you to specify code expiry and domain restriction.