AWS Key Management Service vs OpenStack Barbican

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.

OpenStack Barbican is the OpenStack Key Manager service for storing, provisioning, and managing secrets such as keys, certificates, passwords, and raw binary data. Its barbican-api component provides an OpenStack-native REST API for managing secrets; barbican-worker and barbican-keystone-listener are also part of the service. The listener manages Barbican’s database records for Keystone projects when those projects are deleted. A plugin architecture lets operators connect software secret stores or hardware such as HSMs. Documented options include KMIP, Dogtag, and Vault secret-store plugins, as well as PKCS#11 crypto plugins. With PKCS#11, master encryption and HMAC keys can reside in an HSM. Operators can develop plugins for storage, generation, and event handling, though support status may be stable, experimental, or out-of-tree. The default Simple Crypto plugin stores its single encryption key in plaintext in barbican.conf, so service-node access must be restricted carefully. Container ACL settings do not carry over to associated secrets, and ACL functionality requires Keystone integration. Barbican is free under Apache 2.0; installation guidance assumes a working OpenStack deployment.