Comparison

Cloak KMS vs other key managers

An honest side-by-side against AWS KMS, Google Cloud KMS, Azure Key Vault, and HashiCorp Vault. Axes are chosen for the case "an AI agent is the caller". If your workload is human-only or already locked to a hyperscaler, your answer may differ.

Last updated 2026-05. Comparisons reflect publicly documented behavior. We welcome corrections at hello@cloakapps.com.

Capability Cloak KMS AWS KMS GCP KMS Azure Key Vault HashiCorp Vault
MCP server (native) Yes
Streamable HTTP, protocol 2025-06-18.
 No
REST/SDK only.
 No
REST/SDK only.
 No
REST/SDK only.
 No
REST/CLI; community wrappers exist.
Scope-bound agent credentials First-class
Distinct from user JWTs; per-credential scopes, instant revoke, rotation.
 Via IAM
Reuses human IAM roles; not agent-shaped.
 Via IAM
Service accounts; same as human roles.
 Via IAM
Managed identities; same as human.
 App roles
AppRole + policies; powerful but DIY.
Signed receipts per operation Default
JWS over RFC 8785, ECDSA P-256. Offline-verifiable in any browser.
 CloudTrail
Audit log; not a portable receipt.
 Cloud Audit Logs
Audit log; not portable.
 Activity log
Audit log; not portable.
 Audit device
Hashed audit trail; you bring storage.
HSM tier FIPS 140-2 L3
PKCS#11 HSM; choose managed or BYO-HSM in self-host.
 FIPS 140-2 L3
CloudHSM tier; standard KMS is L2/L3 multi-tenant.
 FIPS 140-2 L3
Cloud HSM SKU.
 FIPS 140-2 L3
Managed HSM SKU.
 Via plugin
Software by default; HSM via Enterprise + seal/auto-unseal.
Self-host on-prem Yes
Any PKCS#11 HSM. Customer publishes its own JWKS.
 No No No Yes
Self-host is the default deployment.
PDF / AATL signing Batchsign
AATL-trusted PDF signing tied to the same HSM.
 No No No No
File-level encrypt/decrypt for agents Shipping soon
@cloakapps/cloak-encrypt-mcp — local stdio MCP, plaintext stays on agent host.
 Envelope
DIY via SDK envelope encryption.
 Envelope Envelope Transit secrets engine
Vendor lock-in Low
Open formats; receipts verifiable by anyone with the JWKS.
 High
Tied to AWS account/IAM.
 High High Low
Self-hostable; OSS.
Public discovery (llms.txt + mcp.json) Yes
llms.txt, .well-known/mcp.json
 No No No No
Yes ships as a first-class feature Partial achievable but DIY or via a separate product No not available as of the date above

When to pick which

Pick Cloak KMS when
  • AI agents — not just humans — are calling the KMS.
  • You need an offline-verifiable signed receipt for every operation, for auditors or downstream consumers.
  • You want a single platform that covers KMS + file encryption + AATL PDF signing.
  • You want to avoid hyperscaler lock-in or run on-prem against your own HSM.
Pick AWS / GCP / Azure KMS when
  • Your workload is 100% inside one hyperscaler and your callers are services, not agents.
  • Tight IAM integration with that cloud's identity model is more important than portability.
  • Receipts and agent-shaped credentials are not requirements for your auditors.
Pick HashiCorp Vault when
  • You need a self-hosted secrets manager covering far more than crypto (DB creds, PKI, transit, dynamic secrets).
  • You have the platform team to operate Vault Enterprise + HSM seal at scale.
  • You can layer your own receipt/signing convention on top of Vault's audit device.
Use both
  • Keep hyperscaler KMS for service-to-service encryption inside that cloud.
  • Use Cloak KMS as the agent-facing surface and the system of record for receipts.
  • Both can sit behind the same on-prem HSM via PKCS#11.

Try the agent surface in five minutes

Provision a scope-bound agent credential, point any MCP-capable host at kms.cloakapps.com/kms/mcp, sign a digest, verify the receipt.

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