On Parallelizing the CryptMT Stream Cipher

Fast stream ciphers are used extensively for encrypted data transmission in mobile networks and over multi- gigabit links. CryptMT, a recently proposed stream cipher, is one of the final candidates for standardization by the European Union´s eSTREAM project. Cryptanalysis of CryptMT has discovered no feasible attacks thus far. We present a scalable technique for parallelizing CryptMT and present an area-efficient hardware implementation on a field- programmable gate array (FPGA). On the Xilinx Virtex-2 Pro FPGA, a 2x parallelization delivers throughputs of up to 16 Gbits/s while using minimal logic resources (1,782 slices). This is highly area-efficient compared to implementations of ciphers such as AES. Possibilities for higher degrees of parallelization are also discussed.