High Quality Content by WIKIPEDIA articles! TSIG (Transaction SIGnature) is a computer networking protocol defined in RFC 2845. It is used primarily by the Domain Name System (DNS) to provide a means of authenticating updates to a Dynamic DNS database, although it can also be used between servers and for regular queries. TSIG uses shared secret keys and one-way hashing to provide a cryptographically secure means of identifying each endpoint of a connection as being allowed to make or respond to a DNS update.