DIGITAL SIGNATURE SERVER AND USER TERMINAL

摘要

Disclosed is a digital signature server that simultaneously reduces load on user terminals and server-side load resulting from verifying digital signatures. A signing key matrix (KM) arrays a plurality of signing keys (Ki-j) in a matrix of m rows by n columns, and is stored in a signing key matrix database (21). The relation between a signing key set (CK), which is a set of signing keys arbitrarily selected from each of the n columns thereof, and a user terminal (30), is stored in a relational information database (22). A digital signature generation unit (24) encrypts a content digest (D), which is generated on the basis of digital content (C), with each of n signing keys that are included in the signing key matrix (KM), and generates a digital signature in a matrix configuration thereupon.