Fix flow in introduction.

index.html

@@ -314,43 +314,21 @@
       <h2>Introduction</h2>
 
       <p>
-The use of shared secrets for [=authentication=] and [=authorization=], such as
-the use of passwords, has resulted in a variety of security failures over the
-past several decades. To address these security failures, systems can upgrade to
-the use of
-<a href="https://en.wikipedia.org/wiki/Public-key_cryptography">
-asymmetric cryptography</a>, which uses digital signatures that are far more
-difficult to compromise. However, one shortcoming of digital signatures is
-the difficulty in disseminating the information, such as public cryptographic
-keys, to those that would need to verify the security of the digital signature.
+[=Controller documents=] enable the verification of proofs created by the
+controller of an identifier. They provide [=verification methods=] that express
+public cryptographic material, such as public keys, for verifying proofs created
+by the controller of the identifier for specific purposes, such as
+authentication, attestation, key agreement (for encryption), and capability
+invocation and delegation. [=Controller documents=] also provide [=services=]
+related to the identifier, for example to request additional information for
+verification.
       </p>
 
       <p>
-A [=controller document=] contains cryptographic material and identifies
-service endpoints that can be used to verify proofs from, and interact
-with, the [=controller=] of an identifier.
-      </p>
-      <p>
-[=Controller documents=] enable the verification of proofs created
-by the controller of an identifier. They provide [=verification methods=]
-that express public cryptographic material, such as public keys, for
-verifying proofs created by the controller of the
-identifier for specific purposes, such as
-authentication, attestation, key agreement (for encryption), and capability invocation
-and delegation.
-      </p>
-      <p>
-Controller Documents also provide [=services=] related to the identifier,
-for example to request additional information for verification.
-      </p>
-      <p>
-In other words, the
-controller document contains the information necessary to communicate
-with, and/or prove that specific actions were taken by, the controller
-of an identifier,
-including material for
-cryptographic proofs and service endpoints for additional
-communications.
+In other words, the controller document contains the information necessary to
+communicate with, and/or prove that specific actions were taken by, the
+controller of an identifier, including material for cryptographic proofs and
+service endpoints for additional communications.
       </p>
 
       <p>