The GNU Nettle cryptographic library is out with a major new update that introduces support for SLH-DSA, the post-quantum signature scheme selected by NIST for the FIPS 205 standard.
Nettle 4.0 fully supports SLH-DSA signatures for this standard also known as SPHINCS+ algorithm. SLH-DSA is stateless and secure against classic and quantum computing attacks. SLH-DSA can ultimately serve as a replacement to RSA, ECDSA, and similar algorithms.
The Nettle 4.0 release does break some APIs/ABIs for developers to be aware of. Among the ABI changes are introducing 16-byte alignment for some types to help with SIMD load and store instruction performance.
There are also various fixes, mandating C99 compiler support for building this library, and various other changes but the main one is the SLH-DSA signature support.
More details on the GNU Nettle 4.0 release via the mailing list announcement.
