Compact Implementations of LEA Block Cipher for Low-End Microprocessors

  • Hwajeong Seo
  • Zhe Liu
  • Jongseok Choi
  • Taehwan Park
  • Howon KimEmail author
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9503)


In WISA’13, a novel lightweight block cipher named LEA was released. This algorithm has certain useful features for hardware and software implementations, i.e., simple ARX operations, non-S-box architecture, and 32-bit word size. These features are realized in several platforms for practical usage with high performance and low overheads. In this paper, we further improve 128-, 192- and 256-bit LEA encryption for low-end embedded processors. Firstly we present speed optimization methods. The methods split a 32-bit word operation into four byte-wise operations and avoid several rotation operations by taking advantages of efficient byte-wise rotations. Secondly we reduce the code size to ensure minimum code size. We find the minimum inner loops and optimize them in an instruction set level. After then we construct the whole algorithm in a partly unrolled fashion with reasonable speed. Finally, we achieved the fastest LEA implementations, which improves performance by 10.9 % than previous best known results. For size optimization, our implementation only occupies the 280B to conduct LEA encryption. After scaling, our implementation achieved the smallest ARX implementations so far, compared with other state-of-art ARX block ciphers such as SPECK and SIMON.


Low-power encryption algorithm AVR Speed optimization 


  1. 1.
    Aranha, D.F., Dahab, R., López, J., Oliveira, L.B.: Efficient implementation of elliptic curve cryptography in wireless sensors. Adv. Math. Commun. 4(2), 169–187 (2010)MathSciNetCrossRefzbMATHGoogle Scholar
  2. 2.
    Atmel Corporation. ATmega128(L) Datasheet (Rev. 2467O-AVR-10/06), October 2006.
  3. 3.
    Beaulieu, R., Shors, D., Smith, J., Treatman-Clark, S., Weeks, B., Wingers, L.: The SIMON and SPECK block ciphers on AVR 8-bit microcontrollersGoogle Scholar
  4. 4.
    Beaulieu, R., Shors, D., Smith, J., Treatman-Clark, S., Weeks, B., Wingers, L.: The SIMON and SPECK families of lightweight block ciphers. IACR Cryptology ePrint Archive, 2013:404 (2013)Google Scholar
  5. 5.
    Gouvêa, C.P.L., López, J.: High speed implementation of authenticated encryption for the MSP430X microcontroller. In: Hevia, A., Neven, G. (eds.) LatinCrypt 2012. LNCS, vol. 7533, pp. 288–304. Springer, Heidelberg (2012)CrossRefGoogle Scholar
  6. 6.
    Osvik, D.A., Bos, J.W., Stefan, D., Canright, D.: Fast software AES encryption. In: Hong, S., Iwata, T. (eds.) FSE 2010. LNCS, vol. 6147, pp. 75–93. Springer, Heidelberg (2010)CrossRefGoogle Scholar
  7. 7.
    Hong, D., Lee, J.-K., Kim, D.-C., Kwon, D., Ryu, K.H., Lee, D.-G.: LEA: a 128-Bit block cipher for fast encryption on common processors. In: Kim, Y., Lee, H., Perrig, A. (eds.) WISA 2013. LNCS, vol. 8267, pp. 1–24. Springer, Heidelberg (2014)CrossRefGoogle Scholar
  8. 8.
    Seo, H., Liu, Z., Park, T., Kim, H., Lee, Y., Choi, J., Kim, H.: Parallel implementations of LEA. In: Lee, H.-S., Han, D.-G. (eds.) ICISC 2013. LNCS, vol. 8565, pp. 256–274. Springer, Heidelberg (2014)Google Scholar

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  • Hwajeong Seo
    • 1
  • Zhe Liu
    • 2
  • Jongseok Choi
    • 1
  • Taehwan Park
    • 1
  • Howon Kim
    • 1
    Email author
  1. 1.School of Computer Science and EngineeringPusan National UniversityBusanRepublic of Korea
  2. 2.Laboratory of Algorithmics, Cryptology and Security (LACS)University of LuxembourgLuxembourg-KirchbergLuxembourg

Personalised recommendations