Blockchain-Assisted Hash-Based Data Signature System and Method

A method for digitally securing data comprising:

• from at least one signing entity via a respective device, receiving at a signing server a query for a signature of a message said request comprising a randomizing function of the message and a current key, said key being one of a plurality of pre-generated keys;
• maintaining a counter of ones of the pre-generated keys previously used by the signing entity;
• maintaining a hash tree data structure having a plurality of input leaves and a root value;
• during each of a series of rounds, including a current round, associating with the signing entity a respective one of the input leaves of the hash tree, each round corresponding to an aggregation interval;
• returning to the signing entity parameters of a first hash chain corresponding to a path through the hash tree from a hash of the query and a current counter value up to the root value of the hash tree for the round during which the request is received;
• submitting the root value for registration in a repository and receiving confirmation of registration;
• and
• incrementing the counter associated with the signing entity, whereby the current key is made unusable for signing in subsequent rounds.