SLH-DSA (Stateless Hash-Based Digital Signature Algorithm (FIPS 205))

Also known as: SPHINCS+

SLH-DSA is the NIST stateless hash-based signature standard (FIPS 205, August 2024), formerly SPHINCS+. Its security relies only on the hash function, offering a conservative fallback if lattice assumptions are broken. Signatures are large (~8-50 KB) and slow, so SLH-DSA is typically reserved for root/anchor keys and firmware signing rather than online telecom signaling.

Categories: Security ControlsProtocols and StandardsInternet and Routing

SLH-DSA in context

Security controls span signaling firewalls (SS7/Diameter/GTP screening), transport encryption (IPsec, TLS, PRINS), identity and access on OSS/BSS, and monitoring at both packet and log level. Controls are audited against GSMA FS.11/FS.19/FS.20/FS.36.

Telecom security is written into standards from 3GPP, GSMA, ETSI, IETF and ITU-T. Understanding which body owns which specification, and how they interlock, is essential for both design and audit work.

To place SLH-DSA in the wider telecom-security picture, review ML-DSA, SIRT, Suricata, HMAC-SHA256, Digital Signature and SHA: each entry cross-references back to this page so you can walk the topic in either direction.

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