I have a project about cryptography.
I want to create a program by C# to embed a secret key into ciphertext, suppose, i had encrypted message to ciphertext c by algorithm Encryption as DES with key k, now i want to insert key k into ciphertext c, my problem: i don't know what algorithm or technical to do it, a algorithm random insertion or a logic technical, and my purpose is middle-man(actacker) can't understand key in ciphertext which contained key, and of course program allows get key from keyed ciphertext.
i have searched by google, but i don't find solution.
help me, nhoc_mientay@yahoo.com