diff --git a/src/components/views/messages/MImageBody.js b/src/components/views/messages/MImageBody.js
index 6ae8a1b54c..8b6794d8cb 100644
--- a/src/components/views/messages/MImageBody.js
+++ b/src/components/views/messages/MImageBody.js
@@ -165,7 +165,6 @@ module.exports = React.createClass({
     render: function() {
         var TintableSvg = sdk.getComponent("elements.TintableSvg");
         var content = this.props.mxEvent.getContent();
-        var cli = MatrixClientPeg.get();
 
         if (content.file !== undefined && this.state.decryptedUrl === null) {
 
diff --git a/src/components/views/messages/MVideoBody.js b/src/components/views/messages/MVideoBody.js
index d29a3ea53e..df707ddcb6 100644
--- a/src/components/views/messages/MVideoBody.js
+++ b/src/components/views/messages/MVideoBody.js
@@ -19,13 +19,22 @@ limitations under the License.
 var React = require('react');
 var filesize = require('filesize');
 
+
 var MatrixClientPeg = require('../../../MatrixClientPeg');
 var Modal = require('../../../Modal');
 var sdk = require('../../../index');
+var DecryptFile = require("../../../utils/DecryptFile")
 
 module.exports = React.createClass({
     displayName: 'MVideoBody',
 
+    getInitialState: function() {
+        return {
+            decryptedUrl: null,
+            decryptedThumbnailUrl: null,
+        };
+    },
+
     thumbScale: function(fullWidth, fullHeight, thumbWidth, thumbHeight) {
         if (!fullWidth || !fullHeight) {
             // Cannot calculate thumbnail height for image: missing w/h in metadata. We can't even
@@ -48,9 +57,88 @@ module.exports = React.createClass({
         }
     },
 
+    _getContentUrl: function() {
+        var content = this.props.mxEvent.getContent();
+        if (content.file !== undefined) {
+            return this.state.decryptedUrl;
+        } else {
+            return MatrixClientPeg.get().mxcUrlToHttp(content.url);
+        }
+    },
+
+    _getThumbUrl: function() {
+        var content = this.props.mxEvent.getContent();
+        if (content.file !== undefined) {
+            return this.state.decryptedThumbnailUrl;
+        } else {
+            return MatrixClientPeg.get().mxcUrlToHttp(content.url, 800, 600);
+        }
+    },
+
+    componentDidMount: function() {
+        var content = this.props.mxEvent.getContent();
+        var self = this;
+
+        if (content.file !== undefined && this.state.decryptedUrl === null) {
+            var thumbnailPromise = Promise.resolve(null);
+            if (content.info.thumbnail_file) {
+                thumbnailPromise = DecryptFile.decryptFile(
+                    content.info.thumbnail_file
+                );
+            }
+            thumbnailPromise.then(function(thumbnailBlob) {
+                DecryptFile.decryptFile(
+                    content.file
+                ).then(function(contentBlob) {
+                    if (self._unmounted) {
+                        return;
+                    }
+                    var contentUrl = window.URL.createObjectURL(contentBlob);
+                    var thumbUrl = null;
+                    if (thumbnailBlob) {
+                        thumbUrl = window.URL.createObjectURL(thumbnailBlob);
+                    }
+                    self.setState({
+                        decryptedUrl: contentUrl,
+                        decryptedThumbnailUrl: thumbUrl,
+                    });
+                });
+            }).catch(function (err) {
+                console.warn("Unable to decrypt attachment: ", err)
+                // Set a placeholder image when we can't decrypt the image.
+                self.refs.image.src = "img/warning.svg";
+            });
+        }
+    },
+
+    componentWillUnmount: function() {
+        this._unmounted = true;
+        if (this.state.decryptedUrl) {
+            window.URL.revokeObjectURL(this.state.decryptedUrl);
+        }
+        if (this.state.decryptedThumbnailUrl) {
+            window.URL.revokeObjectURL(this.state.decryptedThumbnailUrl);
+        }
+    },
+
+
     render: function() {
         var content = this.props.mxEvent.getContent();
-        var cli = MatrixClientPeg.get();
+
+        if (content.file !== undefined && this.state.decryptedUrl === null) {
+            // Need to decrypt the attachment
+            // The attachment is decrypted in componentDidMount.
+            // For now add an img tag with a spinner.
+            return (
+                <span className="mx_MImageBody" ref="body">
+                <img className="mx_MImageBody_thumbnail" src="img/spinner.gif" ref="image"
+                    alt={content.body} />
+                </span>
+            );
+        }
+
+        var contentUrl = this._getContentUrl();
+        var thumbUrl = this._getThumbUrl();
 
         var height = null;
         var width = null;
@@ -63,8 +151,8 @@ module.exports = React.createClass({
                 height = Math.floor(content.info.h * scale);
             }
 
-            if (content.info.thumbnail_url) {
-                poster = cli.mxcUrlToHttp(content.info.thumbnail_url);
+            if (thumbUrl) {
+                poster = thumbUrl;
                 preload = "none";
             }
         }
@@ -73,7 +161,7 @@ module.exports = React.createClass({
         if (this.props.tileShape === "file_grid") {
             download = (
                 <div className="mx_MImageBody_download">
-                    <a className="mx_MImageBody_downloadLink" href={cli.mxcUrlToHttp(content.url)} target="_blank" rel="noopener">
+                    <a className="mx_MImageBody_downloadLink" href={contentUrl} target="_blank" rel="noopener">
                         {content.body}
                     </a>
                     <div className="mx_MImageBody_size">
@@ -86,7 +174,7 @@ module.exports = React.createClass({
             var TintableSvg = sdk.getComponent("elements.TintableSvg");
             download = (
                 <div className="mx_MImageBody_download">
-                    <a href={cli.mxcUrlToHttp(content.url)} target="_blank" rel="noopener">
+                    <a href={contentUrl} target="_blank" rel="noopener">
                         <TintableSvg src="img/download.svg" width="12" height="14"/>
                         Download {content.body} ({ content.info && content.info.size ? filesize(content.info.size) : "Unknown size" })
                     </a>
@@ -96,7 +184,7 @@ module.exports = React.createClass({
 
         return (
             <span className="mx_MVideoBody">
-                <video className="mx_MVideoBody" src={cli.mxcUrlToHttp(content.url)} alt={content.body}
+                <video className="mx_MVideoBody" src={contentUrl} alt={content.body}
                     controls preload={preload} autoPlay={false}
                     height={height} width={width} poster={poster}>
                 </video>