Update language: DIDs enable cryptographic authentication (#29)

- Clarify that DIDs can enable cryptographic authentication
- Specify example of how that can happen
- Simplified language to address remaining feedback

index.html

@@ -141,8 +141,8 @@ <h1 id="title">Decentralized Identifier Working Group Charter</h1>
 an authority (e.g. DNS Registrars).
           </li>
           <li>
-The controller of a DID can cryptographically authenticate themselves
-(e.g. DID-based website login) .
+DIDs enable cryptographic authentication of a DID controller
+(e.g. DID-based website login using a WebAuthn/FIDO token).
           </li>
           <li>
 DIDs provide discovery information for bootstrapping into secure and