diff --git a/README.md b/README.md
index b577e5c..63a6412 100644
--- a/README.md
+++ b/README.md
@@ -13,13 +13,24 @@ npm i oauth2orize-facebook -S
 
 ## Usage
 
+Before using this package, you should enable the 'Require App Secret' option in the advanced settings of your Facebook app.
+You also must provide the app secret by exporting it
+
+```sh
+export FB_APP_SECRET={your Facebook app secret}
+```
+
+or by adding FB_APP_SECRET={your Facebook app secret} to your .env file.
+
+Then, you can have fun
+
 ```js
 var oauth2orize = require('oauth2orize');
 var oauth2orizeFacebook = require('oauth2orize-facebook');
 
 var server = oauth2orize.createServer();
 
-server.exchange(oauth2orizeFacebook(function (client, profile, scope, cb) {
+server.exchange(oauth2orizeFacebook(['email', 'first_name', 'last_name'], function (client, profile, scope, cb) {
   // Get access token from client and Facebook profile information.
   var accessToken = 'access token';
 
diff --git a/lib/index.js b/lib/index.js
index 132117e..872b7dd 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -5,10 +5,22 @@ var objectAssign = require('object-assign');
 
 var getFacebookProfile = require('./util').getFacebookProfile;
 
-module.exports = function (opts, issue) {
+module.exports = function (opts, fields, issue) {
+  if (Array.isArray(opts)) {
+    issue = fields;
+    fields = opts;
+    opts = null;
+  }
+
   if (typeof opts === 'function') {
     issue = opts;
     opts = null;
+    fields = null;
+  }
+
+  if (fields != null && !Array.isArray(fields)) {
+    throw new Error('You must specify the Facebook profile fields as an array.' +
+      'Also, make sure you have permission to access these fields');
   }
 
   if (typeof issue !== 'function') {
@@ -28,7 +40,7 @@ module.exports = function (opts, issue) {
   return function facebook(req, res, next) {
     if (!req.body) {
       return next(new Error('Request body not parsed. ' +
-        'Use bodyParser middleware.'));
+          'Use bodyParser middleware.'));
     }
 
     // The `user` property of `req` holds the authenticated user. In the case
@@ -40,65 +52,66 @@ module.exports = function (opts, issue) {
 
     if (!token) {
       return next(new AuthorizationError(
-        'Missing Facebook access token!', 'invalid_request'));
+          'Missing Facebook access token!', 'invalid_request'));
     }
 
-    getFacebookProfile(token, function (err, profile) {
-      if (err) {
-        return next(new AuthorizationError(
-          'Could not get Facebook profile using provided access token.',
-          'invalid_request'
-        ));
-      }
-
-      if (scope) {
-        for (var i = 0, len = separators.length; i < len; i++) {
-          // Only separates on the first matching separator.
-          // This allows for a sort of separator "priority"
-          // (ie, favors spaces then fallback to commas).
-          var separated = scope.split(separators[i]);
-
-          if (separated.length > 1) {
-            scope = separated;
-            break;
-          }
+    getFacebookProfile(fields, token, function (err, profile) {
+        if (err) {
+          console.log(err);
+          return next(new AuthorizationError(
+              'Could not get Facebook profile using provided access token.',
+              'invalid_request'
+          ));
         }
 
-        if (!Array.isArray(scope)) {
-          scope = [ scope ];
-        }
-      }
+        if (scope) {
+          for (var i = 0, len = separators.length; i < len; i++) {
+            // Only separates on the first matching separator.
+            // This allows for a sort of separator "priority"
+            // (ie, favors spaces then fallback to commas).
+            var separated = scope.split(separators[i]);
+
+            if (separated.length > 1) {
+              scope = separated;
+              break;
+            }
+          }
 
-      var issued = function (err, accessToken, refreshToken, params) {
-        if (err) {
-          return next(err);
+          if (!Array.isArray(scope)) {
+            scope = [ scope ];
+          }
         }
 
-        if (!accessToken) {
-          return next(new AuthorizationError(
-            'Permissions was not granted.', 'invalid_grant'));
-        }
+        var issued = function (err, accessToken, refreshToken, params) {
+          if (err) {
+            return next(err);
+          }
+
+          if (!accessToken) {
+            return next(new AuthorizationError(
+                'Permissions was not granted.', 'invalid_grant'));
+          }
 
-        var json = { 'access_token': accessToken };
+          var json = { 'access_token': accessToken };
 
-        if (refreshToken) {
-          json['refresh_token'] = refreshToken;
-        }
+          if (refreshToken) {
+            json['refresh_token'] = refreshToken;
+          }
 
-        if (params) {
-          objectAssign(json, params);
-        }
+          if (params) {
+            objectAssign(json, params);
+          }
 
-        json['token_type'] = json['token_type'] || 'bearer';
-        json = JSON.stringify(json);
+          json['token_type'] = json['token_type'] || 'bearer';
+          json = JSON.stringify(json);
 
-        res.setHeader('Content-Type', 'application/json');
-        res.setHeader('Cache-Control', 'no-store');
-        res.setHeader('Pragma', 'no-cache');
-        res.end(json);
-      };
+          res.setHeader('Content-Type', 'application/json');
+          res.setHeader('Cache-Control', 'no-store');
+          res.setHeader('Pragma', 'no-cache');
+          res.end(json);
+        };
 
-      issue(client, profile, scope, issued);
+        issue(client, profile, scope, issued);
     });
   };
 };
diff --git a/lib/util.js b/lib/util.js
index d63956a..c70c667 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -1,10 +1,14 @@
 'use strict';
-
+require('dotenv');
 var request = require('request');
+var crypto = require('crypto');
+
+exports.getFacebookProfile = function (fields, accessToken, cb) {
+  var appSecretProof = crypto.createHmac('sha256', process.env.FB_APP_SECRET).update(accessToken).digest('hex');
+  var fieldsString = fields.join();
 
-exports.getFacebookProfile = function (accessToken, cb) {
   request({
-    url: 'https://graph.facebook.com/me?access_token=' + accessToken,
+    url: 'https://graph.facebook.com/me?fields=' + fieldsString + '&access_token=' + accessToken + '&appsecret_proof=' + appSecretProof,
     json: true
   },
   function (err, res, body) {
diff --git a/package.json b/package.json
index a22a51e..37cbcd6 100644
--- a/package.json
+++ b/package.json
@@ -17,6 +17,7 @@
     "test": "eslint lib/"
   },
   "dependencies": {
+    "dotenv": "^4.0.0",
     "object-assign": "^2.0.0",
     "request": "^2.53.0"
   },