From 0d63e90b67e52c8c3e13d6733a80ddf9735234c6 Mon Sep 17 00:00:00 2001
From: Steve Moyer <smoyer1@selesy.com>
Date: Thu, 24 Oct 2024 10:54:43 -0400
Subject: [PATCH] docs(did): add comment explaining why some ECDSA public keys
 are "coerced" to Secp256k1 public keys

---
 did/crypto.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/did/crypto.go b/did/crypto.go
index 8eed59a..da2a7aa 100644
--- a/did/crypto.go
+++ b/did/crypto.go
@@ -200,6 +200,13 @@ func codeForCurve(pubKey crypto.PubKey) (multicodec.Code, error) {
 	}
 }
 
+// secp256k1.S256 is a valid ECDSA curve, but the go-libp2p/core/crypto
+// package treats it ask a different type and has a different format for
+// the raw bytes of the public key.
+//
+// If a valid ECDSA public key was created the secp256k1.S256 curve, this
+// function will "convert" it from a crypto.ECDSAPubKey to a
+// crypto.Secp256k1PublicKey.
 func coerceECDSAToSecp256k1(pubKey crypto.PubKey) (crypto.PubKey, error) {
 	stdPub, err := crypto.PubKeyToStdKey(pubKey)
 	if err != nil {