Hawk: a signature scheme inspired by the Lattice Isomorphism Problem.

A fast, compact and floating-point free post-quantum signature scheme.

Read the specification document (PDF)


Hawk is a cryptographic signature scheme that is intended to be secure against both classical and quantum computers.

It was submitted on June 1st, 2023 to the Call for additional Digital Signature Schemes organised by NIST.

There are two isochronous implementations available: a "Reference implementation" and an "AVX2 Optimized implementation", which are in the submission package. For the source code, see the GitHub repo.



The procedures for generating and verifying signatures are fast on all devices, including low end devices.

Hawk-512 signature generation and verification take <0.1ms on an average desktop PC.


The keys and signature sizes are all rather small.

A Hawk-512 public key is 1024 bytes, a signature 555 bytes.

Well-suited for various hardware

Hawk is free of floating-point arithmetic, i.e. CPUs do not need to support double.

Moreover, Hawk-512 only needs 14 kiB of RAM to work.


Hawk has the following private/public key and signature sizes.

Hawk-512 Hawk-1024
Targeted security Level 1 Level 5
Private key size 184 bytes 360 bytes
Public key size 1024 bytes 2440 bytes
Signature size 555 bytes 1221 bytes

Below, the performance of Hawk is listed. Speed is expressed in clock cycles, and RAM usage in bytes.

Hawk-512 Hawk-1024
Targeted security Level 1 Level 5
Speed on a x86 ("Coffee Lake") with AVX2 (clock cycles)
Key pair generation 8 432 840 43 660 958
Signature generation 85 372 180 816
Signature verification 148 224 302 861
Speed on an ARM Cortex M4 (clock cycles)
Key pair generation 52 316 870 225 658 496
Signature generation 2 801 495 6 179 673
Signature verification 1 418 539 3 006 983
RAM usage (bytes)
Key pair generation 14 336 27 648
Signature generation 4 096 7 168
Signature verification 6 144 11 264


  • Round 1

    17 July 2023

    NIST announced 40 candidates in the first round of the “onramp” call for additional signature schemes. There are 6 other lattice-based signature schemes.

  • Website released

    29 June 2023

    The initial website is released.

  • Hawk submitted

    1 June 2023

    Hawk was submitted to the Call for additional Digital Signature Schemes organised by NIST.