Lockup is a FreeBASIC command line encryption program demonstrating an implementation of the blowfish encryption algorithm, and the use of MD5 to hash a password. The implementation is from Public Domain sources, so you can use the code in your own programs without licensing restrictions. The download includes test code and data to verify the implementation. Note that one source file, md5test.bas, includes GPL test data, and GPL licensing conditions apply to that file.
For my own use I have a GUI version of Lockup that is integrated with my password manager, and file manager, so I can encrypt or decrypt files by right clicking on them in the file manager and selecting Lockup from the context menu. I have WinXP and Linux versions of the same programs.
Please note that I am not an expert in this cryptology. I have verified the implementation of the algorithms against test data, but I can guarantee nothing else.
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