nips/98.md

NIP-98
======

HTTP Auth
---------

`draft` `optional`

This NIP defines an ephemeral event used to authorize requests to HTTP servers using nostr events.

This is useful for HTTP services which are built for Nostr and deal with Nostr user accounts.

## Nostr event

A `kind 27235` (In reference to [RFC 7235](https://www.rfc-editor.org/rfc/rfc7235)) event is used.

The `content` SHOULD be empty.

The following tags MUST be included.

* `u` - absolute URL
* `method` - HTTP Request Method

Example event:
```json
{
  "id": "fe964e758903360f28d8424d092da8494ed207cba823110be3a57dfe4b578734",
  "pubkey": "63fe6318dc58583cfe16810f86dd09e18bfd76aabc24a0081ce2856f330504ed",
  "content": "",
  "kind": 27235,
  "created_at": 1682327852,
  "tags": [
    ["u", "https://api.snort.social/api/v1/n5sp/list"],
    ["method", "GET"]
  ],
  "sig": "5ed9d8ec958bc854f997bdc24ac337d005af372324747efe4a00e24f4c30437ff4dd8308684bed467d9d6be3e5a517bb43b1732cc7d33949a3aaf86705c22184"
}
```

Servers MUST perform the following checks in order to validate the event:
1. The `kind` MUST be `27235`.
2. The `created_at` timestamp MUST be within a reasonable time window (suggestion 60 seconds).
3. The `u` tag MUST be exactly the same as the absolute request URL (including query parameters).
4. The `method` tag MUST be the same HTTP method used for the requested resource.

When the request contains a body (as in POST/PUT/PATCH methods) clients SHOULD include a SHA256 hash of the request body in a `payload` tag as hex (`["payload", "<sha256-hex>"]`), servers MAY check this to validate that the requested payload is authorized.

If one of the checks was to fail the server SHOULD respond with a 401 Unauthorized response code.

Servers MAY perform additional implementation-specific validation checks.

## Request Flow

Using the `Authorization` HTTP header, the `kind 27235` event MUST be `base64` encoded and use the Authorization scheme `Nostr`

Example HTTP Authorization header:
```
Authorization: Nostr 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
```

## Reference Implementations
- C# ASP.NET `AuthenticationHandler` [NostrAuth.cs](https://gist.github.com/v0l/74346ae530896115bfe2504c8cd018d3)