BLZZRD

11-Mar-16 Markku-Juhani O. Saarinen m.saarinen@qub.ac.uk

Centre for Secure Information Technologies (CSIT) ECIT, Queen's University Belfast, UK

Introduction

This is an educational implementation of the BLZZRD Ring-LWE signature scheme, described in more detail in Markku-Juhani O. Saarinen: "Arithmetic Coding and Blinding for Lattice Cryptography", which is available as IACR ePrint 2016/276.

BLZZRD is an evolutionary version of the BLISS signature scheme originally published in Crypto '13: Léo Ducas, Alain Durmus, Tancrède Lepoint, Vadim Lyubashevsky: "Lattice Signatures and Bimodal Gaussians" Extended version of that paper is available as IACR ePrint 2013/383. More specifically, this code also implements the BLISS-B optimizations by Léo Ducas, described in IACR ePrint 2014/874.

However, this is only educational code. Some shortcuts have been taken and therefore this should not be used in production in its current form.

The main experimental modifications are:

• Modified random oracle for Post-Quantum Security
• Arithmetic Coding for Signature Compression and Decompression
• Experimental blinding side-channel protections for polynomial ring arithmetic and Gaussian sampling.

Compiling and running

Assuming that you get the tarball open:

d$ make
gcc -Wall -Ofast -march=native -DPOLY_BLINDING -DGAUSS_BLINDING  -c main.c -o main.o
gcc -Wall -Ofast -march=native -DPOLY_BLINDING -DGAUSS_BLINDING  -c ntt32.c -o ntt32.o
gcc -Wall -Ofast -march=native -DPOLY_BLINDING -DGAUSS_BLINDING  -c distr.c -o distr.o
gcc -Wall -Ofast -march=native -DPOLY_BLINDING -DGAUSS_BLINDING  -c blzrand.c -o blzrand.o
gcc -Wall -Ofast -march=native -DPOLY_BLINDING -DGAUSS_BLINDING  -c sha3.c -o sha3.o
gcc -Wall -Ofast -march=native -DPOLY_BLINDING -DGAUSS_BLINDING  -c param.c -o param.o
gcc -Wall -Ofast -march=native -DPOLY_BLINDING -DGAUSS_BLINDING  -c keygen.c -o keygen.o
gcc -Wall -Ofast -march=native -DPOLY_BLINDING -DGAUSS_BLINDING  -c pubpriv.c -o pubpriv.o
gcc -Wall -Ofast -march=native -DPOLY_BLINDING -DGAUSS_BLINDING  -c pack.c -o pack.o
gcc -Wall -Ofast -march=native -DPOLY_BLINDING -DGAUSS_BLINDING  -c gari.c -o gari.o
gcc -Wall -Ofast -march=native -DPOLY_BLINDING -DGAUSS_BLINDING  -c blind.c -o blind.o
gcc  -o xtest main.o ntt32.o distr.o blzrand.o sha3.o param.o keygen.o pubpriv.o pack.o gari.o blind.o  -lm

$ ./xtest 
CLASS 1 x 1000   Signature avg. 5858.5 bits
CLASS 2 x 1000   Signature avg. 5184.5 bits
CLASS 3 x 1000   Signature avg. 6392.4 bits
CLASS 4 x 1000   Signature avg. 6881.4 bits

That last line indicates success.

Have fun.

Cheers, -Markku

ABSOLUTELY NO WARRANTY WHATSOEVER