index.md

rfc	start_date	decision_date	pr	status
11	2018-08-13	2018-09-04	/pull/26	approved

Multihash

Summary

This RFC proposes to change the method to qualify hashes from using prefixes sha-256: to using Multihash.

This RFC is not backwards compatible in the same sense as RFC0010

Motivation

Currently, the specification defines a custom sha-256: prefix for stringified hexadecimal hashes to qualify them as SHA256. With this approach parsers must be done specifically for registers and registers must standarise any hashing algorithm needed by users. Relying on a standard helps benefiting from that standards ecosystem.

Explanation

The proposal is to adopt Multihash. Their specification is quite thorough but the gist is to replace any of our sha-256: to 1220.

• 0x12 stringified as 12: Hashing function sha2-256.
• 0x20 stringified as 20: Digest length.

For example, instead of the current JSON:

[{
  "index-entry-number":"6",
  "entry-number":"6",
  "entry-timestamp":"2016-04-05T13:23:05Z",
  "key":"GB",
  "item-hash":["sha-256:6b18693874513ba13da54d61aafa7cad0c8f5573f3431d6f1c04b07ddb27d6bb"]
}]

We will use

[{
  "index-entry-number":"6",
  "entry-number":"6",
  "entry-timestamp":"2016-04-05T13:23:05Z",
  "key":"GB",
  "item-hash":["12206b18693874513ba13da54d61aafa7cad0c8f5573f3431d6f1c04b07ddb27d6bb"]
}]

And similarly, the GET /items/{hash} endpoint will expect something like this:

GET /items/12206b18693874513ba13da54d61aafa7cad0c8f5573f3431d6f1c04b07ddb27d6bb HTTP/1.1
Accept: application/json