Secure signed radix-r recoding methods for constrained-embedded devices

Dong Guk Han, Sung Kyoung Kim, Ho Won Kim, Kyo Il Chung, Jongin Lim

Research output: Chapter in Book/Report/Conference proceedingConference contribution


This paper presents two recoding methods for a radix-r representation of a secret scalar which are resistant to SPA. These recoding methods are left-to-right so they can be interleaved with a left-to-right scalar multiplication, removing the need to store both a scalar and its recoding. Next, we show the ideas of left-to-right recoding for a radix-r representation lead to simplified recoding methods for a binary representation. In general our proposed algorithms asymptotically require additional (w + 1)-digit and w-bit of RAM in the case of width-w radix-r representation and a special case when r = 2, respectively, which is independent from the digit (bit) size n of the scalar and considerably reduces the required space comparing with previous methods which require n-digit (bit) of RAM additional memory to store the recoded scalar. Consequently, thanks to its left-to-right nature, the scalar multiplication based on it is by far more convenient with respect to memory consumption.

Original languageEnglish
Title of host publicationInformation Security Practice and Experience - Third International Conference, ISPEC 2007, Proceedings
PublisherSpringer Verlag
Number of pages16
ISBN (Print)3540721592, 9783540721598
Publication statusPublished - 2007
Event3rd International Conference on Information Security Practice and Experience, ISPEC 2007 - Hong Kong, Hong Kong
Duration: 2007 May 72007 May 9

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume4464 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Other3rd International Conference on Information Security Practice and Experience, ISPEC 2007
Country/TerritoryHong Kong
CityHong Kong


  • Elliptic curve cryptosystems
  • Left-to-right
  • Pairingbased cryptosystems
  • Right-to-left
  • Side channel attacks

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science


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