Add README

README.md

@@ -0,0 +1,34 @@
+[![Go Reference](https://pkg.go.dev/badge/github.com/kangaroux/go-wow-srp6.svg)](https://pkg.go.dev/github.com/kangaroux/go-wow-srp6)
+
+This library implements the SRP6 protocol used in World of Warcraft.
+
+```
+go get github.com/kangaroux/go-wow-srp6
+```
+
+Check out the [gomaggus](https://github.com/Kangaroux/gomaggus) authd server for a reference on how this library is used (sorry, but it's 2AM and I'm too tired to write up a full example, unlucky).
+
+## SRP6 Overview
+
+> The [Gtker guide](https://gtker.com/implementation-guide-for-the-world-of-warcraft-flavor-of-srp6/#srp6-overview) provides an approachable and comprehensive look at SRP6. This library is heavily based on this guide.
+
+SRP6 is a protocol used to authenticate users over an insecure connection.
+The client and server do a series of handshakes to prove to each other that
+they know the user's password. At the end of the exchange, both parties will have
+a shared session key.
+
+Prior to login, the user registers an account. The server stores the username,
+salt, and password verifier.
+
+At the login screen, after the user has entered their username and password,
+the handshaking begins:
+
+1. Client sends the username (challenge).
+2. Server responds with the salt, the server's public key, and some parameters (challenge reply).
+   - [gomaggus](https://github.com/Kangaroux/gomaggus/blob/fb845ea23e35ba9186a61a0865460fefdb6e5aa4/authd/handler/loginchallenge.go#L80) generates a fake salt if the username doesn't exist to protect against data mining, though this isn't necessary.
+3. Client computes a proof and sends it (proof).
+4. Server computes the same proof and compares it.
+   - Proofs match: auth success, the client/server now have a shared session key.
+   - Proofs don't match: auth failed, the client is kicked.
+
+The session key is primarily used by the realm server for encryption (`realmd` in gomaggus, `worldd` in most other implementations). When the client connects to the realm server, they must once again prove they know the session key.

srp.go

@@ -1,4 +1,4 @@
-// Package srp implements the SRP6 variant used in World of Warcraft.
+// Package srp implements the SRP6 protocol used in World of Warcraft.
 //
 // See the README for more info: https://github.com/kangaroux/go-wow-srp6
 package srp