I have set of binary data files among one of my applications and for security issues I should encrypt and decrypt files for every use. This is quite well but the process is killing. I use Blowfish to perform ciphering and it's really slow in both functions. I can understand that if someone wants to extract my data from the binary files, he/she should have a recognition about my file pattern but I'm afraid that would be nothing hard to guess.
Is there any way to lock access for users to read binary files with use of encryption or other things?