Cloak KMS · human-approved authority for agents

Give the agent an operation.
Keep control of the key.

Developers integrate through API or MCP. A human account grants the agent a limited scope. Cloak KMS performs only the permitted signing, verification, encryption, decryption, or derivation operation and returns only the permitted result. Supported protected-file workflows can add a signed receipt.

Agents do not provision the root of trust or receive private-key material. Hardware assurance depends on the configured custody path.

Use KMS when an agent needs consequential authority

The differentiator is the authorization and evidence layer, not inexpensive hardware by itself.

Production signing or decryption

Grant only the operation, key, environment, expiry, and usage the workflow needs.

Human approval boundaries

Keep sensitive actions behind an explicit approval or pre-authorized policy.

Custody choice

Evaluate with software keys, then use managed or customer-controlled hardware when required.

Every cryptographic operation you need

Operations run inside the configured key boundary: SoftHSM software tokens for free and trial users, or hardware HSM custody for BYO and hosted pilot deployments.

Key generation & storage

Generate RSA-2048/4096, ECDSA P-256/P-384, and AES-256 keys inside a SoftHSM sandbox or HSM-backed vault. Keys are assigned a stable key_id and are not returned as plaintext.

Sign & verify

Pass a digest to POST /keys/{id}/sign and get a signature back. The signing operation happens inside the configured KMS boundary; your app never receives private key material.

Key rotation

Schedule automatic rotation on any key. The old key is retired after a configurable grace period. Re-encryption of dependent data is handled by the KMS — your app sees the same key_id.

Envelope encryption

Wrap your own data-encryption keys with a KMS-managed key encryption key (KEK). Store the wrapped DEK anywhere; in HSM deployments, the KEK stays inside the hardware boundary.

Multi-tenant key isolation

Each account's keys are logically isolated. Hosted HSM pilots can add dedicated hardware partitioning; BYO HSM deployments can keep the hardware boundary under your control.

Operation records and workflow receipts

KMS enforces the credential scope for each operation. Signed receipts are shipped for supported protected-file operations; KMS-wide signed operation receipts and the full analytics view remain planned.

mcp_agent.py MCP tool call
# Agent signs a document digest via KMS
result = mcp.call_tool(
  "kms_sign",
  {
    "alias":     "agent-signing-key",
    "keyId":     "0101",
    "algorithm": "ECDSA_SHA_256",
    "digestHex": digest_hex
  }
)

# Signature returned; private-key material is not returned
sig = result["signatureBase64"]

# Agent provisions a new key
key = mcp.call_tool(
  "kms_create_masterkey",
  {
    "alias":    "project-alpha-signing",
    "keyType":  "ECC_SECP256R1",
    "keyUsage": "SIGN"
  }
)
MCP-native · agent credential management

Your agents need keys too

AI agents that sign artifacts, encrypt outputs, or issue credentials need their own key identity — and that identity needs to be auditable, scoped, and revocable. Cloak KMS gives every agent a named key in the software sandbox first, with BYO HSM and paid hosted HSM pilots available for hardware custody.

The MCP server exposes nine KMS primitives — list, read public key, create, delete, sign, verify, encrypt, decrypt, ECDH-derive — with scoped agent credentials per tool. See the full tool reference. KMS-wide signed operation receipts are planned; today, signed receipts are available in supported protected-file workflows.

  • kms_create_masterkey — provision a KMS key (ECC, RSA, AES)
  • kms_sign — sign a SHA-256 digest inside the configured key boundary
  • kms_encrypt / kms_decrypt — bytes-level RSA-OAEP / AES-CBC
  • Per-agent credential scopes; revoke or rotate instantly
Read the agent integration guide →

Choose your key custody path

Start in a software-key sandbox. Managed smartcard-HSM access is capacity-limited and subject to plan controls. Customer-controlled or other production HSM options require a compatibility and deployment assessment. Receipt support is workflow-specific.

Free Software Sandbox

SoftHSM-backed trial keys

  • Software-token key operations
  • REST + MCP API access
  • KMS-wide signed operation receipts — planned
  • Strict limits; not production custody
Start free sandbox →
Tutorial Trial
Smartcard HSM

Guided hardware smartcard flow

  • Hardware smartcard HSM tutorial
  • Capacity-limited, time-boxed trial
  • PKCS#11 setup guidance
  • Best for evaluation and training
Request trial →
Production HSM assessment
YubiHSM · CloudHSM · BYO

Durable hardware custody

  • YubiHSM 2 — compact dedicated HSM
  • AWS CloudHSM — compatibility assessed per deployment
  • Bring your own HSM — PKCS#11 compatibility assessed
  • Hosted HSM pilot subject to capacity, policy, and agreed limits
Request fit assessment →
Better together · Cloak Files × KMS

The protected-file workflow runs on KMS

Cloak Files is a first-party consumer of this KMS: every file protect, open, and revoke resolves to a scoped KMS key operation. It is the working example of the integration pattern — your product can use the same one.

How the file layer maps to key operations

  • Protect a file → the per-file key is wrapped per recipient with a KMS masterkey: ECDH derivation (ecdh-derive) for ECC identities, RSA-OAEP for RSA.
  • Open a file → a fresh unwrap inside the configured key boundary, authorized against the recipient identity and file policy at that moment.
  • Revoke access → KMS denies the next unwrap. Copies of the encrypted file anywhere in the world stop opening.
  • Sign a receipt → ECDSA (SHA-256) signing with a KMS-held key, in supported protected-file workflows.

What the integration buys you

Agents act, keys stay put

An agent protecting or reading customer files holds only a scoped, TTL-limited KMS credential. Private-key material is never in the prompt, the code, or the agent runtime.

HSM-rooted file keys

In hardware custody paths, the masterkey behind every file key is generated inside a PKCS#11 HSM — smartcard HSM, YubiHSM 2, AWS CloudHSM, or BYO — and is non-exportable. Wrap and unwrap execute inside the device.

One custody ladder, no rework

Evaluate the full file workflow on SoftHSM sandbox keys, then move the same keyspace concept to managed or customer-controlled hardware. The file APIs and MCP tools do not change.

For developer teams

Build on KMS. Add hardware when the risk requires it.

Start with scoped credentials and software keys. Move to managed hardware subject to capacity and service limits, or connect a supported customer-controlled HSM after an asynchronous fit assessment.

REST API

The full KMS surface over OAuth2 — generate keys, sign, verify, encrypt, decrypt, manage keystores and policies. Best for first-party services and deep integrations (it's how Cloak Files uses KMS).

MCP endpoint

A self-service, least-privilege door for AI agents and scoped app integrations — owner-bound, TTL-limited, revocable credentials with sign / verify / encrypt / decrypt / key tools. No client provisioning needed.

Remote setup assessment

Start with an asynchronous deployment questionnaire, device compatibility guidance, and documented PKCS#11 setup. Add paid remote engineering help only after the technical fit is clear.

Request setup assessment →

Send the workload, custody requirement, and device model. We will return a written fit assessment and next steps.

Start with scoped authority in the sandbox

Evaluate the human-to-agent grant and key-operation flow with software keys. Move to managed or customer-controlled hardware only when the production threat model requires it.

Governed by the OMMAU Charter — humans authorize, agents execute, receipts record supported actions.