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E-04 Encryption Service

Brick E: Data, RAG, context, memory. French version: E-04-encryption-service

1. Role and responsibilities​

Envelope application encryption with keys managed in OpenBao, backed by a KMS or HSM.

  • Encrypt / decrypt
  • Manage and rotate keys per tenant
  • BYOK / HYOK via KMS/HSM

2. Position in the architecture and interactions​

  • Callers: Checkpoints, Object Storage, Token Vault, Media.
  • Execution path: Synchronous.
  • Every interaction goes through the Control Plane API v1 (/v1) behind the API Gateway (D-14).

3. Open source component and developed part​

  • Open source: OpenBao, KMS cloud ou HSM PKCS#11
  • Developed: API and key metadata.
  • External integration through an adapter eai/integrations/<system>.py with an in-process fallback when the URL is not configured.

4. Data model​

Tables (schema eai, tenant_id RLS):

  • eai.encryption_keys

Common columns: id uuid, tenant_id uuid NOT NULL, created_at, updated_at; RLS policy current_setting('app.tenant_id', true)::uuid.

5. Contract​

  • Applied contract: no manifest
  • Key fields: key_id, version, algorithm
  • Validation: POST /v1/contracts/{name}/validate; manifest apply: POST /v1/manifests/apply.

6. API endpoints​

  • POST /v1/encryption/encrypt
  • POST /v1/encryption/decrypt
  • GET /v1/encryption/keys
  • POST /v1/encryption/keys
  • POST /v1/encryption/keys/{id}/rotate

Request POST /v1/encryption/encrypt:

{
  "key": "key_tenant_main",
  "plaintext_base64": "SGVsbG8="
}

Response:

{
  "ciphertext": "vault:v3:Zm9v...",
  "key_version": 3
}

7. SDK examples​

Python:

from enterprise_ai import EnterpriseAI

client = EnterpriseAI(base_url="<control-plane-url>", api_key="eai_xxx_secret")
c = client.encryption.encrypt(b"Hello", key="key_tenant_main")

TypeScript:

import { EnterpriseAI } from "@enterprise-ai/sdk";

const client = new EnterpriseAI({ baseUrl: "<control-plane-url>", apiKey: process.env.EAI_API_KEY });
const c = await client.encryption.encrypt({ key: "key_tenant_main", plaintext_base64: "SGVsbG8=" });

Java:

EnterpriseAIClient client = EnterpriseAIClient.builder()
    .baseUrl("<control-plane-url>")
    .apiKey(System.getenv("EAI_API_KEY"))
    .build();
JsonNode c = client.encryption().encrypt(Map.of("key", "key_tenant_main", "plaintext", "Hello"));

Go:

c, _ := eai.NewClient(eai.WithBaseURL("<control-plane-url>"), eai.WithAPIKey(os.Getenv("EAI_API_KEY")))
ct, _ := c.Encryption.Encrypt(ctx, "key_tenant_main", []byte("Hello"))

8. Configuration​

  • Environment variables: EAI_OPENBAO_URL, EAI_OPENBAO_TRANSIT_MOUNT, EAI_DATABASE_URL
  • Helm values keys: global.openbao, global.secretsMode

9. Security controls​

  • The key never leaves OpenBao/HSM
  • Rotation restricted to security_officer
  • Every request carries the tenant resolved from the credential; PostgreSQL RLS
  • Every mutation and policy decision writes a hash-chained audit event

10. Observability​

  • Prometheus metrics: eai_crypto_ops_total{op}
  • Traces: OpenTelemetry spans with GenAI semantic conventions (gen_ai.operation.name, gen_ai.agent.id, gen_ai.tool.name), attributes eai.tenant_id, eai.run_id, traceparent propagation.
  • Audit actions: encryption.key.create, encryption.key.rotate, encryption.decrypt

11. FinOps units​

  • KMS/HSM operations.
  • Emitted as Usage Event (POST /v1/finops/usage) with tenant, project, agent and run.

12. Failure modes and resilience​

  • Old versions kept for decryption
  • Normalized errors (error envelope, message_i18n en/fr)

13. Standalone adoption (client of a client)​

  • enterprise_ai.encryption + OpenBao.
  • SDK: enterprise_ai.privacy / dlp / knowledge_bases / memory / retention / lineage
  • Minimal deployment: Helm chart with controlPlane.enabled=true and PostgreSQL; disabled external components use their in-process fallback.

14. Acceptance tests​

  1. Decryption after rotation works
  2. Cross-tenant access refused
  3. Error returned in fr with Accept-Language: fr

Governed RAG (kit L4)​

eai.crypto.envelope: Tink envelope encryption (one AES256-GCM data key per message, wrapped by an OpenBao transit or local dev key encryption key), rotation, re-wrap without touching the payload, decryption with an old version until it is retired. Tests: tests/test_data_envelope_tink.py.