'Constructing Digital Signatures from a One Way Function' by Leslie Lamport.

https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.228.2958&rep=rep1&type=pdf nostr:note1xxzsg9luaauxptwdyn45q52zpflj3pc9kd8njprvpu6p79z3hnesc76875