Signature Validation – a Dark Art?

Abstract

ETSI Standard EN 319 102-1 (Procedures for Creation and Validation of AdES Digital Signatures; Part 1: Creation and Validation [2]) is a new standard developed by ETSI during the implementation of Mandate M460 and is currently undergoing the EN approval procedure. The standard covers, as the title suggests, the creation and validation of digital signatures. Some experts, who so far were convinced they understood what needs to be done when validating a signature, are confused. To them the standard is either wrong, not understandable or worst case both. This article tries to shed a light into the approach taken but also discusses why signature validation sometimes gets complex, maybe more complex than necessary, and considers whether this complexity can be avoided.