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Dual Not Applicable

URI: https://docs.ankatech.co/errors/dual-not-applicable
HTTP Status: 422 Unprocessable Entity

When you see this

You requested a dual (two-key) projection or operation for a key that does not support it. The dual model only applies to keys whose usage maps to two distinct single-purpose identities.

Common Causes

  • Requesting a DUAL import for a key whose KeyUsage resolves to a single purpose.
  • Applying a dual projection to an algorithm that is inherently single-purpose.
  • Asking for a -enc/-sig split where only one purpose is valid.

Response Example

{
  "type": "https://docs.ankatech.co/errors/dual-not-applicable",
  "title": "Dual Not Applicable",
  "status": 422,
  "detail": "Dual projection is not applicable to this key. The key resolves to a single purpose.",
  "instance": "/api/v3/keys",
  "correlationId": "550e8400-e29b-41d4-a716-446655440000",
  "timestamp": 1730000000
}

Content-Type: application/problem+json — the response follows RFC 7807 Problem Details.

How to Resolve

  1. Import or create the key as a single-purpose key with an explicit purpose.
  2. Only request a dual projection for keys whose usage genuinely spans both encryption and signing.
  3. Review the import metadata and re-submit without the dual request.

For full schema definitions, examples, and interactive testing, see the Developer Hub Reference.