[[Leslie Lamport]] invented hash-based signatures in 1979. The XMSS (eXtended Merkle Signature Scheme)<ref name="BuchmannDahmen2011">{{cite book|last1=Buchmann|first1=Johannes|last2=Dahmen|first2=Erik|last3=Hülsing|first3=Andreas|title=Post-Quantum Cryptography |chapter=XMSS - A Practical Forward Secure Signature Scheme Based on Minimal Security Assumptions |series=Lecture Notes in Computer Science |volume=7071|pages=117–129|year=2011|issn=0302-9743|doi=10.1007/978-3-642-25405-5_8|isbn=978-3-642-25404-8 |citeseerx=10.1.1.400.6086}}</ref> and SPHINCS<ref>{{Cite book|last1=Bernstein|first1=Daniel J.|last2=Hopwood|first2=Daira|last3=Hülsing|first3=Andreas|last4=Lange|first4=Tanja|author4-link=Tanja Lange|last5=Niederhagen|first5=Ruben|last6=Papachristodoulou|first6=Louiza|last7=Schneider|first7=Michael|last8=Schwabe|first8=Peter|last9=Wilcox-O’Hearn|first9=Zooko|title=Advances in Cryptology -- EUROCRYPT 2015 |chapter=SPHINCS: practicalPractical statelessStateless hashHash-basedBased Signatures signatures|year=2015|publisher=Springer Berlin Heidelberg|isbn=9783662467992|editor-last=Oswald|editor-first=Elisabeth|editor-link= Elisabeth Oswald |series=Lecture Notes in Computer Science|volume=9056|pages=368–397|language=en|doi=10.1007/978-3-662-46800-5_15|editor-last2=Fischlin|editor-first2=Marc|citeseerx = 10.1.1.690.6403}}</ref><ref>{{cite web|title=SPHINCS: Introduction|url=http://sphincs.cr.yp.to/}}</ref> hash-based signature schemes were introduced in 2011 and 2015, respectively. XMSS was developed by a team of researchers under the direction of [[Johannes Buchmann]] and is based both on Merkle's seminal scheme and on the 2007 Generalized Merkle Signature Scheme (GMSS).<ref>{{cite book|last1=Buchmann|first1=Johannes|last2=Dahmen|first2=Erik|last3=Klintsevich|first3=Elena|last4=Okeya|first4=Katsuyuki|last5=Vuillaume|first5=Camille|title=Applied Cryptography and Network Security |chapter=Merkle Signatures with Virtually Unlimited Signature Capacity |series=Lecture Notes in Computer Science |date=2007|volume=4521|pages=31–45|doi=10.1007/978-3-540-72738-5_3|isbn=978-3-540-72737-8 |language=en|doi-access=free}}</ref> A multi-tree variant of XMSS, XMSS<sup>''MT''</sup>, was described in 2013.<ref>{{cite book|last1=Hülsing|first1=Andreas|last2=Rausch|first2=Lea|last3=Buchmann|first3=Johannes|title=Security Engineering and Intelligence Informatics |chapter=Optimal Parameters for XMSS MT |series=Lecture Notes in Computer Science |date=2013|volume=8128|pages=194–208|doi=10.1007/978-3-642-40588-4_14|language=en|isbn=978-3-642-40587-7}}</ref>
