Abstract: A computer-implemented method and system for clustering electronic documents generates a signature for each document in the form of a sequence of hashes, and saves each signature in a collection of fields of a data store, each hash in a separate field. A search and indexing engine is configured to create an index of all stored signature hashes and to return a document similarity rating in response to a fielded signature query listing hash, field pairs defining a reference signature. Documents which signatures are returned to the query with a similarity rating exceeding a threshold are assigned to a same cluster.