This document summarizes a seminar on digital signatures. It defines a digital signature as an encrypted hash value of a message that is unique to the document and verifies the identity of the owner. Digital signatures provide authenticity, integrity, and non-repudiation for electronic documents. The technology uses public and private key pairs, with the private key used to generate signatures and the public key used to verify signatures. Some challenges of digital signatures include the cost of certification authorities and ensuring private keys remain secure, but they enable secure e-commerce, e-governance and other applications.