KMs

KMS is an acronym used in information technology with several distinct meanings. The two most common are Key Management Service, a Microsoft licensing technology, and Key Management System, a term used for cryptographic key management. Depending on context, KMS may also refer to other domain-specific services or tools.

In the Microsoft licensing context, KMS stands for Key Management Service. It provides a network-based method to activate volume-licensed Windows and Office products within an organization. A dedicated KMS host is configured with a special key, and client machines activate by contacting that host rather than each product key individually. To begin activating, an organization typically must meet a minimum threshold of activated machines (commonly 25 Windows clients or 5 Windows servers). Once activated, clients must periodically renew activation by contacting the KMS host, roughly every 180 days. KMS activation is often used alongside DNS-based discovery or manual configuration of the KMS host name. It is designed to simplify large-scale deployments and to remain compliant with volume licensing terms.

In cryptography, KMS stands for Key Management System or Key Management Service, referring to systems that oversee the lifecycle of cryptographic keys. Functions include key generation, storage, rotation, access control, audit logging, and revocation. KMS may integrate with hardware security modules (HSMs) and PKI infrastructures. Cloud providers offer KMS services that centralize key management and enable cryptographic operations (encryption, decryption, signing) through fine-grained access policies, automatic auditing, and regional data handling. Examples include AWS Key Management Service, Google Cloud KMS, and Azure Key Vault, each designed to support secure, scalable key governance across applications and services.