.comsec is a generic top-level domain listed by IANA. Its IANA-designated manager is VeriSign, Inc..
Search a specific .comsec name to check availability and use the technical page for documented eligibility rules. A seller’s standard price does not decide whether an applicant or a particular name qualifies.
Compare registration, renewal and transfer separately when seller observations are available. A standard tariff does not include a premium-domain quote or confirm that a specific name is available.
Yes. The root delegation for .comsec has a published DS record. That is not evidence that a registrar can submit DS records for an individual domain.