Digital Signatures is an important technology that allows documents and transactions to be signed and sealed electronically in a way that preserves the data integrity of the document and provides absolute proof of the identity of the signer. This technology facilitates the transition to complete paperless environments and has been adopted by most legal systems around the world. But Digital Signature systems present a serious practical problem when trying to deploy them for wide use. This problem is centred on the question of how to handle the digital signature keys for a large community of users. This presentation examines the problem of key management for Digital Signature systems and suggests a solution, named CoSign, which automatically centrally manages all the keys and certificates throughout their lifecycle. With such a solution the use of Digital Signatures becomes simple for administrators to deploy, easy for users to use, and therefore practical to implement in the real world.