/ˌziː-ɛs-ˈkeɪ/
n. “The key that signs your DNS zone like a digital seal.”
ZSK, short for Zone Signing Key, is a cryptographic key used in DNSSEC (Domain Name System Security Extensions) to digitally sign the records within a DNS zone. It ensures the integrity and authenticity of the DNS data, allowing resolvers to verify that the information has not been tampered with.
Key characteristics of a ZSK include:
- Zone-Level Signing: Signs all resource records in a DNS zone except for the delegation-related keys.
- Shorter Lifespan: Typically rotated more frequently than the Key Signing Key (KSK) to reduce exposure if compromised.
- Part of DNSSEC Chain: Works in conjunction with the KSK to create a trust hierarchy for DNS validation.
- Ensures Data Integrity: Prevents DNS spoofing or cache poisoning attacks by enabling cryptographic verification.
Conceptually, the ZSK acts like a signature pen for a specific DNS zone — every time a DNS record is published or updated, it is “signed” using the ZSK so that clients and resolvers can trust its authenticity.
In essence, ZSK is a critical component of DNSSEC that provides ongoing security for DNS zones, enabling users to trust the accuracy and integrity of the domain information they rely on.