Attestation Signing

HappyView can sign records with an ECDSA (secp256k1) keypair so their origin can be verified later. Lua scripts call atproto.sign() to attach an inline signature to a record and atproto.verify_signature() to check one. HappyView's implementation follows the atproto attestation spec.

How it works

1. HappyView loads or generates a secp256k1 keypair on startup
2. atproto.sign(record) encodes the record to DAG-CBOR, computes its CID, and signs the CID with the private key
3. The signature is added to the record's signatures array as an inline object
4. atproto.verify_signature(record, sig, repo_did) recomputes the CID and verifies the signature

The repo DID is included in the signed data — a signature for one user's record can't be replayed against another's. Any modification to the record invalidates the signature.

Setup

Attestation signing is enabled by default — HappyView generates a keypair on first startup and persists it to the instance_settings database table. No configuration is required.

To use an explicit key instead, set the ATTESTATION_PRIVATE_KEY environment variable:

The key ID defaults to a did:web derived from your PUBLIC_URL. For example, PUBLIC_URL=https://happyview.example.com produces a key ID of did:web:happyview.example.com#attestation.

Priority order

HappyView checks for signing configuration in this order:

1. Environment variables — if ATTESTATION_PRIVATE_KEY is set, it's used
2. Database — if previously generated keys exist in instance_settings, they're loaded
3. Auto-generation — a new key is generated and persisted to the database

If key loading fails for any reason, signing is disabled and atproto.sign / atproto.verify_signature will be nil in Lua scripts.

Using in Lua scripts

Available in queries, procedures, and index hooks via the atproto API.

Signing a record

function handle()
  local r = Record(collection, input)
  r:save()

  local sig = atproto.sign({ text = input.text, createdAt = input.createdAt })
  return { uri = r._uri, cid = r._cid, signature = sig }
end

The returned signature object:

{
  "$type": "your.app.attestation",
  "key": "did:web:happyview.example.com#attestation",
  "signature": {
    "$bytes": "base64-encoded-signature"
  }
}

Verifying a signature

function handle()
  local record = db.get(params.uri)
  if not record then
    return { error = "not found" }
  end

  local sig = record.signatures and record.signatures[1]
  if not sig then
    return { record = record, verified = false }
  end

  local valid = atproto.verify_signature(record, sig, record.did)
  return { record = record, verified = valid }
end

Checking availability

Both functions are nil when no signer is configured:

if atproto.sign then
  record.signature = atproto.sign(record)
end

Signature format

Signatures are stored as objects in the record's signatures array:

Next steps

• atproto API reference — atproto.sign and atproto.verify_signature parameter docs
• Signed Record — save a record with an attestation signature
• Verify Signed Record — fetch a record and verify its signature