---
title: "Cosign a block as a registered witness: {domain, signature} where signature = base64 Ed25519 over canonical(header)."
method: POST
path: "/v1/ledger/blocks/{height}/cosign"
tags: ["Ledger"]
---

# Cosign a block as a registered witness: {domain, signature} where signature = base64 Ed25519 over canonical(header).

`POST /v1/ledger/blocks/{height}/cosign`

## Request

- Base URL: `https://www.rightshold.com`
- URL: `https://www.rightshold.com/v1/ledger/blocks/{height}/cosign`
- Auth: none required

## Path parameters

- `height` string, required

## Headers

- `X-Request-Id` string

## Request body

- object: Fields seen in accepted requests; required ones are proven by tests (omitting each returns a 4xx naming it).
  - `domain` string, required
  - `signature` string
  - `block_hash` string

## Response `200`

OK

- object: Inferred from 8 recorded responses; required fields appeared in every one; additional properties may appear.
  - `created` boolean, required
  - `cosignature` object, required
    - `domain` string, required
    - `key_id` string, required
    - `public_key_pem` string, required
    - `signature` string, required
    - `at` string, required
    - `block_hash` string, required

## Other responses

- `400`: Problem details: a stable error code, type URI, title, status and an explanation
- `401`: Problem details: a stable error code, type URI, title, status and an explanation
- `404`: Problem details: a stable error code, type URI, title, status and an explanation
- `405`: Problem details: a stable error code, type URI, title, status and an explanation
- `422`: Problem details: a stable error code, type URI, title, status and an explanation
- `429`: Request budget exhausted; retry after Retry-After seconds
- `500`: Problem details: a stable error code, type URI, title, status and an explanation
- `4XX`: {error, detail}

---

[API](https://skmtc.dev/rightshold/apis/rightshold-api.md) · [All operations](https://skmtc.dev/rightshold/apis/rightshold-api/llms.txt) · [OpenAPI document](https://skmtc.dev/rightshold/apis/rightshold-api/revisions/cfe84fdde1ca?raw)