Update verification section based on input from #59.

index.html

@@ -722,9 +722,14 @@ <h1>Verification</h1>
 applicable to only some claims.
       </p>
       <section>
-        <h3>Structural Validity</h3>
+        <h3>Syntax</h3>
+        <ul>
+          <li>Document is syntactically valid (e.g. JSON, JSON-LD).</li>
+        </ul>
+      </section>
+      <section>
+        <h3>Credential</h3>
         <ul>
-          <li>Document is valid JSON-LD.</li>
           <li>Required properties are present. For example, for a
           Credential, <code>type</code> and <code>claim</code> are
           required.</li>
@@ -734,33 +739,54 @@ <h3>Structural Validity</h3>
         </ul>
       </section>
       <section>
-        <h3>Entity Validity</h3>
-        <p>
-A number of checks must be implemented to ensure a set of entities related
-to a Credential have mutually compatible properties and are trustworthy.
-        </p>
+        <h3>Issuer</h3>
         <ul>
           <li>The <code>issuer</code> id must match expectations. Likely,
           that means it is the id of a known and trusted <a>entity
           profile</a>.</li>
           <li>Recent metadata about the <code>issuer</code> which was published
           by the issuer MUST be available.</li>
+        </ul>
+      </section>
+      <section>
+        <h3>Subject</h3>
+        <ul>
           <li>The claim subject identifier must match expectations.
           Likely, that means it is the id of a known and trusted
           <a>entity profile </a> for the subject of the claim. If the
           entity that is subject of a claim has transmitted it to the
           inspector-verifier, the subject may be able to prove ownership of key
           identifying properties such as email address(es) and public
           key(s).</li>
-          <li>The <code>issued</code> date must be in the expected range.
-          For example, an inspector-verifier may wish to ensure that the recorded
-          issued date of valid claims is not in the future.</li>
+        </ul>
+      </section>
+      <section>
+        <h3>Signature</h3>
+        <ul>
           <li>The document signature is available in the form of a known
           signature suite.</li>
+          <li>Required signature properties are present. For example, for a
+          Linked Data Signature, <code>type</code>, <code>created</code>,
+          <code>creator></code>, and <code>signatureValue</code> are present.
+          </li>
           <li>The public key associated with the signature is available
           and a trustworthy link between this signing key and the
           issuer's <a>entity profile</a> may be established. The key must
           not be revoked or expired.</li>
+          <li>The cryptographic signature is valid.</li>
+        </ul>
+      </section>
+      <section>
+        <h3>Expiration</h3>
+        <ul>
+          <li>The <code>issued</code> date must be in the expected range.
+          For example, an inspector-verifier may wish to ensure that the recorded
+          issued date of valid claims is not in the future.</li>
+        </ul>
+      </section>
+      <section>
+        <h3>Revocation</h3>
+        <ul>
           <li>If revocation instructions are present, the claim must not
           have been revoked.</li>
         </ul>