Lightweight coprocessor for koblitz curves: 283-bit ecc including scalar conversion with only 4300 gates

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


Colleges, School and Institutes

External organisations

  • Catholic University of Leuven


We propose a lightweight coprocessor for 16-bit microcontrollers that implements high security elliptic curve cryptography. It uses a 283-bit Koblitz curve and offers 140-bit security. Koblitz curves offer fast point multiplications if the scalars are given as specific τ-adic expansions, which results in a need for conversions between integers and τ-adic expansions. We propose the first lightweight variant of the conversion algorithm and, by using it, introduce the first lightweight implementation of Koblitz curves that includes the scalar conversion. We also include countermeasures against side-channel attacks making the coprocessor the first lightweight coprocessor for Koblitz curves that includes a set of countermeasures against timing attacks, SPA, DPA and safe-error fault attacks. When the coprocessor is synthesized for 130nm CMOS, it has an area of only 4, 323 GE. When clocked at 16 MHz, it computes one 283-bit point multiplication in 98ms with a power consumption of 97. 70 μW, thus, consuming 9. 56 μJ of energy.


Original languageEnglish
Title of host publicationCryptographic Hardware and Embedded Systems - CHES 2015
Subtitle of host publication17th International Workshop, Saint-Malo, France, September 13-16, 2015, Proceedings
EditorsTim Güneysu, Helena Handschuh
Publication statusPublished - 13 Sep 2015
EventInternational Workshop on Cryptographic Hardware and Embedded Systems, CHES 2015 - Saint-Malo, France
Duration: 13 Sep 201516 Sep 2015

Publication series

NameLecture Notes in Computer Science
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


ConferenceInternational Workshop on Cryptographic Hardware and Embedded Systems, CHES 2015


  • Elliptic curve cryptography, Koblitz curves, Lightweight implementation, Side-channel resistance