AWS Key Management Service vs Azure Managed HSM

AWS Key Management Service creates and controls cryptographic keys for data encryption and digital signatures. It centralizes key lifecycles and permissions, including separate control over administrators and key users. KMS supports symmetric encryption, asymmetric signing or encryption pairs, and HMAC generation and verification. The AWS Encryption SDK can use KMS as a key provider for local application encryption and decryption. Integrations include Amazon S3, EBS, RDS, DynamoDB, Lambda, and CloudTrail. With CloudTrail enabled, requests can record the user, time, API action, and key. AWS says hardware security modules validated to FIPS 140-3 Security Level 3 protect key material and operations, with plaintext keys kept only in volatile HSM memory. Multi-Region keys support cross-Region workflows; external key stores keep material in a customer-managed external manager. KMS scales with demand but has default key and request limits. The listed plan is $1 a month per KMS key, prorated hourly.

Azure Managed HSM is a cloud service for managing cryptographic keys backed by hardware security modules. It supports customer-managed keys, automatic key rotation, audit logs and key import through a web-accessed service. Both listed key types are supported. The Standard B1 plan is a Managed HSM pool billed by hourly usage fee per HSM pool; no price is provided. Azure lists no free plan. The cloud deployment model suits organisations that want managed HSM capabilities rather than a self-hosted installation. Key import allows existing keys to be brought into the service, while automatic rotation handles scheduled key changes. Audit logs provide activity records for review. Teams evaluating the service can focus on whether HSM-backed protection, customer control, import, rotation and logging meet their key-management needs, and whether hourly pool billing fits their usage.