Stream vs block ciphers for scan encryption

Construction of Stream Ciphers from Block Ciphers and their Security

With well-established encryption algorithms like DES or AES at hand, one could have the impression that most of the work for building a cryptosystem -for example a suite of algorithms for the transmission of encrypted data over the internet is already done. But the task of a cipher is very specific: to encrypt or decrypt a data block of a specified length. Given an plaintext of arbitrary length...

Block Ciphers and Stream Ciphers: The State of the Art

In these lecture notes we survey the state of the art in symmetric key encryption, in particular in the block ciphers and stream ciphers area. The areas of symmetric key encryption has been very active in the last five years due to growing interest from academic and industry research, standardization efforts like AES, NESSIE and CRYPTREC, as well as due to ease of government control over export...

Building Stream Ciphers from Block Ciphers and their Security

Exploring Cipherspace: Combining stream ciphers and block ciphers

This paper looks at the possibility of combining a block cipher and a stream cipher to get a strong hybrid cipher. It includes two specific proposals for combining AES-128 and RC4-128 to get a cipher that takes a 256-bit key and is significantly faster than AES-256, and arguably more secure. One is immune to algebraic attacks.

Public key encryption using block ciphers

A method for deriving a public key encryption system from any ‘conventional’ (secret key) block cipher is described. The method is related to, but improves upon, Merkle’s ’puzzle system’.