v/vlib/x/crypto/slhdsa/README.md

slhdsa

Experimental module of NIST FIPS-205 Stateless Hash-Based Digital Signature Standard (SLH-DSA) in V

About

SLH-DSA was a quantum resistent cryptographic digital signature standard that was approved and publicly published by NIST at August, 2024. Its availables on NIST FIPS 205.
SLH-DSA allow builds relatively big signaturue size with small key (16 - 32 bytes key). The signatures range from ±8K - ±50K depending on the type chosen.

Note

This module wraps and written on top of SLH-DSA functionality availables on latest release of recent OpenSSL library. Based on the history, this functionality was added in OpenSSL 3.5. So, make sure, you have required version of OpenSSL library installed. For simple guides how to build and install latest OpenSSL library on unix-like box, see install-latest-ssl.md

Basic

SLH-DSA signature scheme is constructed using other hash-based signature schemes as components. SLH-DSA was comes with set of predefined parameter that describes security categories, ie:

• What is underlying hash algorithm used in the mean of process.
  The standard defines two's hash algorithm family availables, sha2 family and shake family
• Security bits number of parameter set
• Whether the parameter set was designed to create relatively small signatures ('s') or to have relatively fast signature generation ('f').
  See Table. 2 SLH-DSA parameter sets in the standard document.
  

This parameter set represented by this opaque on this module:

pub enum Kind {
	// SHA2-based family
	sha2_128s = C.NID_SLH_DSA_SHA2_128s
	sha2_128f = C.NID_SLH_DSA_SHA2_128f
	sha2_192s = C.NID_SLH_DSA_SHA2_192s
	sha2_192f = C.NID_SLH_DSA_SHA2_192f
	sha2_256s = C.NID_SLH_DSA_SHA2_256s
	sha2_256f = C.NID_SLH_DSA_SHA2_256f
	// SHAKE-based family
	shake_128s = C.NID_SLH_DSA_SHAKE_128s
	shake_128f = C.NID_SLH_DSA_SHAKE_128f
	shake_192s = C.NID_SLH_DSA_SHAKE_192s
	shake_192f = C.NID_SLH_DSA_SHAKE_192f
	shake_256s = C.NID_SLH_DSA_SHAKE_256s
	shake_256f = C.NID_SLH_DSA_SHAKE_256f
}

Example

import x.crypto.slhdsa

fn main() {
	// you can choose and pass the kind of the SLH-DSA parameter to the constructor
	opt := slhdsa.KeyOpts{
		kind: .sha2_128s
		// other options was availables
	}
	mut pv := slhdsa.PrivateKey.new(opt)!

	// Example message
	msg := 'SLH-DSA example message'.bytes()

	// Sign a message using constructed key
	sig := pv.sign(msg)!

	// Then the public key part can verify this signature
	mut pb := pv.public_key()!
	verified := pb.verify(sig, msg)!
	assert verified // true

	// release the resource
	pv.free()
	pb.free()
}