--- a/encrypted-media/encrypted-media.html	Fri Sep 19 15:11:51 2014 -0700
+++ b/encrypted-media/encrypted-media.html	Fri Sep 19 16:05:51 2014 -0700
@@ -558,13 +558,23 @@
       <li>
 <p>Run the following steps asynchronously:</p>
         <ol>
+          <li><p>If the <var>init data</var> is not valid for <var title="true">initDataType</var>, reject <var>promise</var> with a new <code><a href="http://www.w3.org/TR/dom/#exception-domexception">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
+          <li>
+<p>Let <var>sanitized init data</var> be a validated and/or sanitized version of <var>init data</var>.</p>
+            <div class="note">The user agent should thoroughly validate the Initialization Data before passing it to the CDM.
+              This may include verifying values are within reasonable limits, stripping irrelevant data or fields, pre-parsing it, sanitizing it, and/or generating a fully sanitized version.
+              The user agent should check that the length and values of fields are reasonable.
+              Unknown fields should be rejected or removed.
+              For Initialization Data formats that support multiple entries, the user agent should remove entries that are not needed by the CDM.
+            </div>
+          </li>
+          <li><p>If the previous step failed, reject <var>promise</var> with a new <code><a href="http://www.w3.org/TR/dom/#exception-domexception">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
           <li><p>Let <var title="true">session id</var> be the empty string.</p></li>
           <li><p>Let <var title="true">message</var> be null.</p></li>
           <li><p>Let <var title="true">cdm</var> be the CDM loaded during the <a href="#dom-create">initialization</a> of <var title="true">media keys</var>.</p></li>
           <li>
 <p>Use the <var title="true">cdm</var> to execute the following steps:</p>
             <ol>
-              <li><p>If the <var>init data</var> is not valid for <var title="true">initDataType</var>, reject <var>promise</var> with a new <code><a href="http://www.w3.org/TR/dom/#exception-domexception">DOMException</a></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
               <li><p>If the <var>init data</var> is not supported by the <var title="true">cdm</var>, reject <var>promise</var> with a new <code><a href="http://www.w3.org/TR/dom/#exception-domexception">DOMException</a></code> whose name is <code><a href="#dfn-NotSupportedError">"NotSupportedError"</a></code>.</p></li>
               <li>
 <p>Follow the steps for the first matching condition from the following list:</p>

--- a/encrypted-media/encrypted-media.xml	Fri Sep 19 15:11:51 2014 -0700
+++ b/encrypted-media/encrypted-media.xml	Fri Sep 19 16:05:51 2014 -0700
@@ -537,12 +537,21 @@
       <li><p>Let <var>promise</var> be a new promise.</p></li>
       <li><p>Run the following steps asynchronously:</p>
         <ol>
+          <li><p>If the <var>init data</var> is not valid for <var title="true">initDataType</var>, reject <var>promise</var> with a new <code><dom4ref name="exception-domexception">DOMException</dom4ref></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
+          <li><p>Let <var>sanitized init data</var> be a validated and/or sanitized version of <var>init data</var>.</p>
+            <div class="note">The user agent should thoroughly validate the Initialization Data before passing it to the CDM.
+              This may include verifying values are within reasonable limits, stripping irrelevant data or fields, pre-parsing it, sanitizing it, and/or generating a fully sanitized version.
+              The user agent should check that the length and values of fields are reasonable.
+              Unknown fields should be rejected or removed.
+              For Initialization Data formats that support multiple entries, the user agent should remove entries that are not needed by the CDM.
+            </div>
+          </li>
+          <li><p>If the previous step failed, reject <var>promise</var> with a new <code><dom4ref name="exception-domexception">DOMException</dom4ref></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
           <li><p>Let <var title="true">session id</var> be the empty string.</p></li>
           <li><p>Let <var title="true">message</var> be null.</p></li>
           <li><p>Let <var title="true">cdm</var> be the CDM loaded during the <a href="#dom-create">initialization</a> of <var title="true">media keys</var>.</p></li>
           <li><p>Use the <var title="true">cdm</var> to execute the following steps:</p>
             <ol>
-              <li><p>If the <var>init data</var> is not valid for <var title="true">initDataType</var>, reject <var>promise</var> with a new <code><dom4ref name="exception-domexception">DOMException</dom4ref></code> whose name is <code><a href="#dfn-InvalidAccessError">"InvalidAccessError"</a></code>.</p></li>
               <li><p>If the <var>init data</var> is not supported by the <var title="true">cdm</var>, reject <var>promise</var> with a new <code><dom4ref name="exception-domexception">DOMException</dom4ref></code> whose name is <code><a href="#dfn-NotSupportedError">"NotSupportedError"</a></code>.</p></li>
               <li><p>Follow the steps for the first matching condition from the following list:</p>
                 <dl class="switch">