I am working on e-mail security project … It encrypts message text and attachments
I use AES 128-bit key … the problem that it takes significant long time to encrypt large files (> 3mb ) … for txt files I can compress it and encrypt it, but for binary files (pdf, jpg, exe) compression doesn’t help (just get size >= 75% of original file)
So am thinking just to encrypt the header of binary file, how I know header size of binary file in windows?
.NET has built-in AES support. Maybe you were using it in the wrong way.