The XMSS, GMSS and SPHINCS schemes are available in the Java [[Bouncy Castle (cryptography)|Bouncy Castle]] cryptographic APIs.<ref>{{cite web|title=bcgit/bc-java|url=https://github.com/bcgit/bc-java/tree/master/core/src/main/java/org/bouncycastle/pqc/crypto|website=GitHub|language=en|date=2018-12-18}}</ref> LMS<ref>{{cite web|title=wolfCrypt implementations of LMS/HSS and XMSS/XMSS^MT schemesignatures: isbuild options and benchmarks (Intel x86)|url=https://www.wolfssl.com/wolfcrypt-implementations-of-lms-hss-and-xmss-xmssmt-signatures-build-options-and-benchmarks-intel-x86/|website=wolfSSL|language=en|date=2024-06-18}}</ref> and XMSS schemes are available in the [[wolfSSL|wolfSSL]] cryptographic APIs.<ref>{{cite web|title=wolfSSL/wolfssl|url=https://github.com/wolfSSL/wolfssl/blob/master/wolfssl/wolfcrypt/lms.h|website=GitHub|language=en|date=2023-11-22}}</ref> SPHINCS is implemented in the SUPERCOP benchmarking toolkit.<ref>{{cite web|title=SUPERCOP|url=http://bench.cr.yp.to/supercop.html|access-date=2017-05-31|archive-url=https://web.archive.org/web/20150215055126/http://bench.cr.yp.to/supercop.html|archive-date=2015-02-15|url-status=dead}}</ref> Optimised<ref>{{cite web|title=Code|url=https://huelsing.wordpress.com/code/|website=Andreas Hülsing|access-date=2017-05-31|archive-date=2017-08-22|archive-url=https://web.archive.org/web/20170822224019/https://huelsing.wordpress.com/code/|url-status=dead}}</ref> and unoptimised<ref>{{cite web|title=squareUP > Publications|url=http://www.pqsignatures.org/index/publications.html#code|website=www.pqsignatures.org|language=en-gb}}</ref> reference implementations of the XMSS RFC exist. The LMS scheme has been implemented in Python<ref>{{cite web|last1=David|first1=McGrew|title=The hash-sigs package: an implementation of the Leighton–Micali Hierarchical Signature System (HSS).|url=https://github.com/davidmcgrew/hash-sigs/|website=GitHub|language=en|date=2018-05-29}}</ref> and in C<ref>{{cite web|last1=David|first1=McGrew|title=A full-featured implementation of the LMS and HSS Hash Based Signature Schemes from draft-mcgrew-hash-sigs-07.|url=https://github.com/cisco/hash-sigs|website=GitHub|language=en|date=2018-11-22}}</ref> following its Internet-Draft.
