In https://go.dev/cl/528637 the suggested API is

// None return an AuthMethod using "none" authentication defined in RFC 4252 section 5.2.
func None() AuthMethod {

golang/crypto#272

Can you explain why you want to expose the None authmethod? TestClientAuthNone shows how to use the None auth method; it doesn't need client-side configuration.

@hanwen allow client side to send non-auth on their own like password or key
for example, send non after password. this is useful in special client impl

@tg123 thanks for this proposal, can you please provide a real use case for this? For example a server that requires sending the none auth method after the password.

The none auth method is generally used initially just to list the authentication methods that can continue and this is what we already do in our client implementation. As you can see here, none auth is implicitly added to the configured authentication methods.