SQIsign

SQIsign is a <a href="/facts/Post-quantum_cryptography/1qeqUQve">post-quantum</a> <a href="/facts/Signature_scheme/tY7e2pnW">signature scheme</a> submitted to first round of the <a href="/facts/NIST_Post-Quantum_Cryptography_Standardization/2xELnqQz">post-quantum standardisation</a> process. It is based around a <a href="/facts/Proof_of_knowledge/P1rFAT7f">proof of knowledge</a> of an <a href="/facts/Elliptic_curve/60jvaHSA">elliptic curve</a> <a href="/facts/Endomorphism_ring/K1UgpnJK">endomorphism</a> that can be transformed to a signature scheme using the <a href="/facts/Fiat%25E2%2580%2593Shamir_heuristic/JGnJk1uw">Fiat–Shamir transform</a>.
It promises small key sizes between 64 and 128 bytes and small signature sizes between 177 and 335 bytes, which outperforms other post-quantum signature schemes that have a trade-off between signature and key sizes. SQIsign, however, has higher signing and verification times.
The original paper concluded that their <a href="/facts/C_/Ky2No763">C</a> implementation takes 0.6 s for key generation, 2.5 s for a sign operation and 0.05 s or 50 ms for a verification operation.
These times have been improved with new variations like SQIsign-east.
The name stands for "Short Quaternion and Isogeny Signature" as it makes use of <a href="/facts/Isogeny/ngeefttF">isogenies</a> and <a href="/facts/Quaternion/T3tnu7mX">quaternions</a>.

SQIsign open-in-new

SQIsign