---
title: "Submit a post-quantum signature for the transaction"
method: POST
path: "/transactions/{id}/signature"
tags: ["transactions"]
---

# Submit a post-quantum signature for the transaction

`POST /transactions/{id}/signature`

After signing the payload externally, submit the signature and
public key. The service validates the signature, assembles the
signed transaction, and broadcasts it to the Quantum Chain network.

## Path parameters

- `id` string, uuid, required

## Request body

- SubmitSignatureRequest
  - `signature` string, required — Hex-encoded post-quantum signature
  - `publicKey` string, required — Hex-encoded post-quantum public key

## Response `200`

Signature accepted, transaction broadcasting

- Transaction
  - `id` string, uuid, required
  - `tenantId` string, uuid, required
  - `externalId` string
  - `sourceVaultId` string, uuid, required
  - `sourceWalletId` string, uuid, required
  - `destinationAddr` string, required
  - `assetId` string, uuid, required
  - `amount` string, required — Wei-denominated amount as string
  - `fee` string
  - `gasLimit` integer
  - `nonce` integer
  - `status` 'SUBMITTED' | 'QUEUED' | 'PENDING_AML_SCREENING' | 'PENDING_AUTHORIZATION' | 'APPROVED' | 'REJECTED' | 'PENDING_SIGNATURE' | 'SIGNED' | 'BROADCASTING' | 'CONFIRMING' | 'COMPLETED' | 'FAILED' | 'CANCELLED' | 'BLOCKED', required
  - `failureReason` string
  - `chainTxHash` string
  - `blockNumber` integer
  - `confirmations` integer
  - `note` string
  - `metadata` object
  - `createdAt` string, date-time, required
  - `updatedAt` string, date-time
  - `broadcastAt` string, date-time
  - `confirmedAt` string, date-time

## Other responses

- `400` — Invalid signature
- `409` — Transaction not in signable state

---

[API](https://skmtc.net/quantum-chain-pte-ltd/apis/qustody-api.md) · [All operations](https://skmtc.net/quantum-chain-pte-ltd/apis/qustody-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/quantum-chain-pte-ltd/qustody-api/revisions/ecb2cea3c096/schema)