On this page: - What is a digital signature? - How is a digital
signature used for authentication? - How long do digital
signatures remain valid? - What is the legal status of documents
signed with digital signatures? - Can using Digital ID
Certificates help detect altered documents and transmission
errors? What is a digital signature? A digital signature
functions for electronic documents like a handwritten signature
does for printed documents. The signature is a non-forgeable
piece of data that asserts that a named person wrote or
otherwise agreed to the document to which the signature is
attached. A digital signature actually provides a greater degree
of security than a handwritten signature. The recipient of a
digitally signed message can verify both that the message
originated from the person whose signature is attached and that
the message has not been altered either intentionally or
accidentally since it was signed. Furthermore, secure digital
signatures cannot be repudiated; the signer of a document c