This excerpt taken from the VRSN 10-K filed Jul 12, 2007.
Whois Data Specification ICANN
Registry Operator shall provide bulk access by ICANN to up-to-date data concerning domain name and nameserver registrations maintained by Registry Operator in connection with the .com TLD on a daily schedule, only for purposes of verifying and ensuring the operational stability of Registry Services and the DNS. The specification of the content and format of this data, and the procedures for providing access, shall be as stated below, until changed according to the Registry Agreement.
The data shall be provided in three files:
A. Domain file. One file shall be provided reporting on the domains sponsored by all registrars. For each domain, the file shall give the domainname, servername for each nameserver, registrarid, and updateddate.
B. Nameserver file. One file shall be provided reporting on the nameservers sponsored by all registrars. For each registered nameserver, the file shall give the servername, each ipaddress, registrarid, and updateddate.
C. Registrar file. A single file shall be provided reporting on the registrars sponsoring registered domains and nameservers. For each registrar, the following data elements shall be given: registrarid, registrar address, registrar telephone number, registrar e-mail address, whois server, referral URL, updateddate and the name, telephone number, and e-mail address of all the registrars administrative, billing, and technical contacts.
The format for the above files shall be as specified by ICANN, after consultation with Registry Operator.
Procedures for Providing Access
The procedures for providing daily access shall be as mutually agreed by ICANN and Registry Operator. In the absence of an agreement, an up-to-date version (encrypted using a public key supplied by ICANN) of the files shall be placed at least once per day on a designated server and available for downloading by ICANN by Internet File Transfer Protocol.