A new security relation between information rate and state size of a keystream generator

Wireless communication in near field applications is becoming widespread. Most of the devices such as sensor networks or RFID applications are operated in constraint environments and some of these prevalent technologies require security applications. As one conclusion, the design and analysis of lightweight cryptographic algorithms has been one of the favorite research subjects over the last decade. We have seen that mostly lightweight block ciphers have been designed as symmetric encryption algorithms. The main reason is that stream ciphers are supposed to have large internal states due to the strict requirement related to their resistance against tradeoff attacks (time memory data tradeoff (TMDT)). In this work, we introduce a new stream cipher encryption mode by making use of error correcting codes, constituting a new tradeoff between information rate of the employed code and the internal state size of the keystream generator. This tradeoff enables us to decrease the state size without sacrificing the security against TMDT attacks.