Design of Stream Ciphers
Lidong Chen, Guang Gong · 2012
Stream cipher is primarily used in wireless communications, because the trans- mission over a wireless channel has larger error probability than that over a wired link. In stream cipher encryption, each message bit is independently en- crypted. Thus one bit in error in ciphertext only affects one bit in decrypted message. That is, there is no error propagation in the decryption process. There are two ways to design a stream cipher. One is to use a pseudoran- dom sequence generator (PRSG) in the stream cipher mode as introduced in Chapter 2. The other is to convert a block cipher algorithm as a stream cipher model through counter (CTR) mode or cipher feedback (CFB) mode. In this chapter, we explore stream cipher design using a PRSG in stream ci- pher mode. The block cipher CTR mode and CFB mode will be introduced in Chapter 4.