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**ENG6090(4)**. Reconfigurable Computing Systems. A Compact and Efficient FPGA Implementation of DES Algorithm. Saqib, N.A et al. In:International Conference on Reconfigurable Computing and FPGAs, Sept 2004. References.
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**ENG6090(4)** Reconfigurable Computing Systems A Compact and Efficient FPGA Implementation of DES Algorithm Saqib, N.A et al. In:International Conference on Reconfigurable Computing and FPGAs, Sept 2004
References • Wilcox,D et al:A DES ASIC suitable for network encryption at 10Gbs and beyond. In: CHESS 99 • Patterson,C: High performance DES encryption in Virtex FPGA using Jbits. In: Field programmable custom computing machines,FCCM’00 • Swankoski.E et al:A Parallel Architecture for Secure FPGA Symmetric Encryption.In:18th International Parallel and Distributed Processing Symposium,2004 • Wollinger,T:How secure are FPGAs in Cryptographic applications. In:IACR,2003 • Stallings,W:Cryptography and NetworkSecurity:Principles and Practice. Prentice Hall • Wong,K: A single chip implementation of DES algorithm. In:IEEE Globecomm Communication Conf.,Australia, 1998 • www.nist.gov
Outline • Introduction to Cryptography • Why Cryptographic Algorithms on FPGAs • DES Algorithm • DES ASIC Implementation • DES Implementation using JBits • DES Implementation on FPGAs • Summary
Cryptography • Process of transforming data,using keys, to protect its intelligence and unauthorized use • Cryptography and tamper resistance hardware first used for military application • ATM- the “killer application” which pushed technology into commercial mainstream
Cryptography cont’d.. • Technology advances have increased the number of embedded systems in various computing devices • PDAs, GSM mobile phone identification etc have pushed towards low cost crypto-processors • Security of data important for military and commercial applications
Cryptographic algorithms on FPGA • Algorithm Agility-Can be reprogrammed easily for different application • Changing Protocols-Algorithms can be updated, protocols can be changed as standards evolve • Architecture efficiency-Implementations can be optimized for specific parameter set
Cryptographic algorithms on FPGA cont’d.. • Resource efficiency-Can use run time reconfiguration to configure only certain parts • Throughput- Can offer higher throughputs as compared to CPU’s • Development cost-Less design time, can be reprogrammed without additional time/cost penalty
Cryptographic algorithms on FPGA cont’d.. • Ease of experimenting with different architectures without long fabrication waits • Unit cost is also not very significant
DES algorithm • Data Encryption Standard is one of the commonly used block cipher algorithm • It encrypts/decrypts 64-bit blocks using permutations and substitutions • 64-bit key is passed through initial permutation to obtain a new 56-bit key
DES cont’d.. • 64-bit plaintext is permuted to get initial left half and right half of 32 bits • Right half of first round is obtained by passing the text and keys through 16 rounds • In each round, in the first step,permuted 32-bit right half is XORed with 48-bit subkey
DES cont’d.. • The 48-bit output of first stage is transformed into 32-bit by using 8 S-boxes • In the last stage, this 32-bit result is permuted to right half of this stage • This new right half becomes the left half for next iteration
DES cont’d.. DES Algorithm
DES Implementations • Recent DES implementations
DES ASIC implementation • 0.6 micron,105MHz,6.5Watts • Fully pipelined design thereby increasing the throughput
DES Jbits implementation • Hardware-Software approach allowing high speeds and throughput • Sub-key generation moved to software • Saves slices required for 48 XORs per round and key input IOBs • Can be reconfigured at run time • 0.22 micron, 168MHz, 3.2 Watts
DES Jbits implementation cont’d.. Single DES round (1)Unoptimized, (2)Optimized for Jbits implementation
DES on FGPA • Implements parallel and pipelined approach • The main difference in this approach is the parallel implementation of S-boxes • Critical path delay is significantly reduced • Sub-keys are pre computed and stored in memories
DES on FGPA cont’d.. DES implementation on FPGA • Fixed permutations do not occupy much resources which can be implemented by changing wires
DES on FGPA cont’d.. • 64-bit input divided in RIN and LIN • Before next clock cycle old right half is input to REGB and new left is input to REGA • T/A factor is high indicating higher Mbits/s and less area used
Summary • Different applications need fast processing, higher bandwidths, less area etc • These constrained systems implemented on FPGAs for their obvious advantages • Use parallelism and pipelining to maximize performance • Critical path delay, area, power consumption are some of the important parameters to be optimized