Exploring Cipherspace: Combining stream ciphers and block ciphers.
Sandy Harris · IACR Cryptology ePrint Archive · 2008
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.