ICANN, the overseer of the Internet’s namespace, announced this week that it was postponing a scheduled change to the cryptographic key that protects the Domain Name System.

DNSSEC is not invincible. Researchers this week described how a DNSSEC-based flood attack could easily knock a website offline and allow for the insertion of malware or exfiltration of sensitive data. The intent of Domain Name System Security Extensions, or DNSSEC, is to bolster DNS through a series of complex digital signatures. But if it...