IPIP-0351: IPNS Signed Records Response Format on HTTP Gateways

1. Summary

Add IPNS Signed Records response format to the HTTP Gateway.

2. Motivation

Currently, the gateway allows for trustless retrieval of data under the /ipfs namespace, but fetching the data as a CAR, or Block, and then verifying it locally. This is especially important for light IPFS clients, so that they can retrieve data from other gateways without delegating any of the trust to them. Unfortunately, this is not possible under the /ipns namespace.

In contrary to DNSLink, IPNS provides cryptographically-verifiable records that can be verified by the client. This means that, if a gateway is able to provide the IPNS signed record to an HTTP client, trustless retrieval would also be available under the /ipns namespace.

In this IPIP, we propose adding [ipns-record] as a response format to the gateway under the /ipns namespace, allowing for trustless retrieval of IPNS records over HTTP as application/vnd.ipfs.ipns-record content type (multicodec 0x0300).

3. Detailed design

• [trustless-gateway] can now provide a signed IPNS record upon request for /ipns/{ipns-name} path.
• To request the IPNS record, use one of the following methods:
  • Include the Accept: application/vnd.ipfs.ipns-record HTTP header in the request.
  • Include the format=ipns-record query parameter in the request URL.
• The HTTP response containing the verifiable IPNS record will have the following format:
  • Header: Content-Type: application/vnd.ipfs.ipns-record
  • Body: [ipns-record] serialized as the IpnsEntry protobuf.

4. Test fixtures

This IPIP got ratified before gateway-conformance existed.

The reference implementation in Kubo 0.19 provides reusable assertions.

$ ipfs key gen <key-name>
k51Key

$ ipfs name publish /ipfs/bafyHash --key=<key-name> --ttl=<record-ttl>
Published to k51Key: /ipfs/bafyHash

$ ipfs routing get /ipns/k51Key > key.pb

5. Design rationale

The current gateway already supports different response formats via the Accept HTTP header and the format URL query. This IPIP proposes adding one more supported format to that list.