Verisign is a US-based company mostly known for its role as registry operators for the .com and .net generic top-level domains (gTLDs).
On the basis of an agreement with the Internet Corporation for Assigned Names and Numbers (ICANN) – signed in 2016 and valid for a period of eight years – Verisign performs the Domain Name System root zone maintainer function. In doing so, it edits, generates, and signs the root zone file; publishes the root zone file to a root zone file distribution server; and notifies the root server operators of the availability of the root zone file. In simple terms, when, for example, a new gTLD is approved by ICANN, this information is passed on to Verisign, which makes the necessary changes into te root zone (introducing the new gTLD into the root) and distributes the revised root zone file for the root name servers.
Verisign also serves as the zone signing key (ZSK) operator, and, in this role, it publishes the Domain Name System Security Extensions (DNSSEC) Practice Statement for the Root ZSK Operator – a document describing the management, security, and technical specifications for the ZSK function.
In addition, the company acts as a root server operator, by managing 2 of the 13 root servers hostnames (a.root-servers.net and j.root-servers.net).