AES has several different variants: AES-128 AES-192 AES-256 But why would someone prefer use one over another?
It seems like the S-boxes in DES have essentially random values. How were these chosen?
RSA is not designed to be used on long blocks of plaintext like a block cipher, but I need to use it to send a large message. How can I do this?
Does there exist any cryptographic algorithm which encrypts data in such a way that it can only be decrypted after a certain period of time? The only idea that I can think of, is something like this: ...