Question

I am written an algorithm to encrypt and decrypt file using AES.

I am also changing the encrypted file extension to .fenc.

So now the problem is that I am not able to detect the content-type of the file because the file is encrypted and extension also changed.

I am planning to do this: in the encrypted file into the first line I will put the content-type details and after that the encrypted data. And while decrypting the file I will read the first line and after that decrypted the content.

What do you think about this?

Answer 1

Why don’t you just add .fenc to the filename, e.g. mymasterplan.ppt.fenc? That way you can determine the content type based on the filename.