TKEY record

TKEY (transaction key) is a record type of the Domain Name System (DNS). TKEY resource records (RRs) can be used in a number of different modes to establish shared keys between a DNS resolver and name server.

Mode field values

 * 0 – Reserved
 * 1 – Server assignment
 * 2 – Diffie–Hellman key exchange
 * 3 – Generic Security Service Algorithm for Secret Key Transaction
 * 4 – Resolver assignment
 * 5 – Key deletion
 * 6–65534 – Available
 * 65535 – Reserved