diff --git a/packages/security/.gitattributes b/packages/security/.gitattributes
new file mode 100644
index 00000000..9447b90c
--- /dev/null
+++ b/packages/security/.gitattributes
@@ -0,0 +1 @@
+libinjection/* linguist-vendored
\ No newline at end of file
diff --git a/packages/security/.gitignore b/packages/security/.gitignore
new file mode 100644
index 00000000..87ea0c20
--- /dev/null
+++ b/packages/security/.gitignore
@@ -0,0 +1,54 @@
+# See https://www.dartlang.org/tools/private-files.html
+
+# Files and directories created by pub
+.buildlog
+.packages
+.project
+.pub/
+build/
+**/packages/
+
+# Files created by dart2js
+# (Most Dart developers will use pub build to compile Dart, use/modify these 
+#  rules if you intend to use dart2js directly
+#  Convention is to use extension '.dart.js' for Dart compiled to Javascript to
+#  differentiate from explicit Javascript files)
+*.dart.js
+*.part.js
+*.js.deps
+*.js.map
+*.info.json
+
+# Directory created by dartdoc
+doc/api/
+
+# Don't commit pubspec lock file 
+# (Library packages only! Remove pattern if developing an application package)
+pubspec.lock
+
+log.txt
+.dart_tool
+
+# Created by https://www.gitignore.io/api/cmake
+# Edit at https://www.gitignore.io/?templates=cmake
+
+### CMake ###
+CMakeLists.txt.user
+CMakeCache.txt
+CMakeFiles
+CMakeScripts
+Testing
+Makefile
+cmake_install.cmake
+install_manifest.txt
+compile_commands.json
+CTestTestfile.cmake
+_deps
+
+### CMake Patch ###
+# External projects
+*-prefix/
+
+# End of https://www.gitignore.io/api/cmake
+build/
+cmake-build-*
\ No newline at end of file
diff --git a/packages/security/.travis.yml b/packages/security/.travis.yml
new file mode 100644
index 00000000..de2210c9
--- /dev/null
+++ b/packages/security/.travis.yml
@@ -0,0 +1 @@
+language: dart
\ No newline at end of file
diff --git a/packages/security/CHANGELOG.md b/packages/security/CHANGELOG.md
new file mode 100644
index 00000000..3aaa1f19
--- /dev/null
+++ b/packages/security/CHANGELOG.md
@@ -0,0 +1,6 @@
+# 2.0.0-alpha.1
+* Make `ServiceRateLimiter` more fail-proof.
+
+# 2.0.0-alpha
+* Angel 2 updates. Remove previous functionality.
+* Add `CookieSigner`, `RateLimiter`/`InMemoryRateLimiter`/`ServiceRateLimiter`.
\ No newline at end of file
diff --git a/packages/security/LICENSE b/packages/security/LICENSE
new file mode 100644
index 00000000..89074fd3
--- /dev/null
+++ b/packages/security/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2017 The Angel Framework
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/packages/security/README.md b/packages/security/README.md
new file mode 100644
index 00000000..53339b5f
--- /dev/null
+++ b/packages/security/README.md
@@ -0,0 +1,8 @@
+# security
+[![Pub](https://img.shields.io/pub/v/angel_security.svg)](https://pub.dartlang.org/packages/angel_security)
+[![build status](https://travis-ci.org/angel-dart/security.svg)](https://travis-ci.org/angel-dart/security)
+
+Angel middleware designed to enhance application security by patching common Web security
+holes.
+
+**This package is currently going through a major overhaul, for version 2.**
\ No newline at end of file
diff --git a/packages/security/analysis_options.yaml b/packages/security/analysis_options.yaml
new file mode 100644
index 00000000..c230cee7
--- /dev/null
+++ b/packages/security/analysis_options.yaml
@@ -0,0 +1,4 @@
+include: package:pedantic/analysis_options.yaml
+analyzer:
+  strong-mode:
+    implicit-casts: false
\ No newline at end of file
diff --git a/packages/security/example/cookie_signer.dart b/packages/security/example/cookie_signer.dart
new file mode 100644
index 00000000..c2db9ff3
--- /dev/null
+++ b/packages/security/example/cookie_signer.dart
@@ -0,0 +1,56 @@
+import 'dart:io';
+import 'dart:math';
+import 'package:angel_framework/angel_framework.dart';
+import 'package:angel_framework/http.dart';
+import 'package:angel_security/angel_security.dart';
+import 'package:logging/logging.dart';
+import 'package:pretty_logging/pretty_logging.dart';
+
+main() async {
+  // Logging boilerplate.
+  Logger.root.onRecord.listen(prettyLog);
+
+  // Create an app, and HTTP driver.
+  var app = Angel(logger: Logger('cookie_signer')), http = AngelHttp(app);
+
+  // Create a cookie signer. Uses an SHA256 Hmac by default.
+  var signer = CookieSigner.fromStringKey(
+      'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789ab');
+
+  // When a user visits /getid, give them a (signed) uniqid cookie.
+  // When they visit /cookies, print their verified cookies.
+  var rnd = Random.secure();
+
+  // Endpoint to give a signed cookie.
+  app.get('/getid', (req, res) {
+    // Write the uniqid cookie.
+    var uniqid = rnd.nextInt(65536);
+    signer.writeCookie(res, Cookie('uniqid', uniqid.toString()));
+
+    // Send a response.
+    res.write('uniqid=$uniqid');
+  });
+
+  // Endpoint to dump all verified cookies.
+  //
+  // The [onInvalidCookie] callback is optional, but
+  // here we will use it to log invalid cookies.
+  app.get('/cookies', (req, res) {
+    var verifiedCookies = signer.readCookies(req, onInvalidCookie: (cookie) {
+      app.logger.warning('Invalid cookie: $cookie');
+    });
+    res.writeln('${verifiedCookies.length} verified cookie(s)');
+    res.writeln('${req.cookies.length} total unverified cookie(s)');
+    for (var cookie in verifiedCookies) {
+      res.writeln('${cookie.name}=${cookie.value}');
+    }
+  });
+
+  // 404 otherwise.
+  app.fallback((req, res) => throw AngelHttpException.notFound(
+      message: 'The only valid endpoints are /getid and /cookies.'));
+
+  // Start the server.
+  await http.startServer('127.0.0.1', 3000);
+  print('Cookie signer example listening at ${http.uri}');
+}
diff --git a/packages/security/example/main.dart b/packages/security/example/main.dart
new file mode 100644
index 00000000..e69de29b
diff --git a/packages/security/example/pubspec.yaml b/packages/security/example/pubspec.yaml
new file mode 100644
index 00000000..25444875
--- /dev/null
+++ b/packages/security/example/pubspec.yaml
@@ -0,0 +1,8 @@
+name: example
+publish_to: none
+dependencies:
+  angel_production: ^1.0.0
+  angel_redis: ^1.0.0
+  angel_security:
+    path: ../
+  pretty_logging: ^1.0.0
\ No newline at end of file
diff --git a/packages/security/example/rate_limit.dart b/packages/security/example/rate_limit.dart
new file mode 100644
index 00000000..baccb01a
--- /dev/null
+++ b/packages/security/example/rate_limit.dart
@@ -0,0 +1,34 @@
+import 'package:angel_framework/angel_framework.dart';
+import 'package:angel_framework/http.dart';
+import 'package:angel_security/angel_security.dart';
+import 'package:logging/logging.dart';
+import 'package:pretty_logging/pretty_logging.dart';
+
+main() async {
+  // Logging boilerplate.
+  Logger.root.onRecord.listen(prettyLog);
+
+  // Create an app, and HTTP driver.
+  var app = Angel(logger: Logger('rate_limit')), http = AngelHttp(app);
+
+  // Create a simple in-memory rate limiter that limits users to 5
+  // queries per 30 seconds.
+  //
+  // In this case, we rate limit users by IP address.
+  var rateLimiter =
+      InMemoryRateLimiter(5, Duration(seconds: 30), (req, res) => req.ip);
+
+  // `RateLimiter.handleRequest` is a middleware, and can be used anywhere
+  // a middleware can be used. In this case, we apply the rate limiter to
+  // *all* incoming requests.
+  app.fallback(rateLimiter.handleRequest);
+
+  // Basic routes.
+  app
+    ..get('/', (req, res) => 'Hello!')
+    ..fallback((req, res) => throw AngelHttpException.notFound());
+
+  // Start the server.
+  await http.startServer('127.0.0.1', 3000);
+  print('Rate limiting example listening at ${http.uri}');
+}
diff --git a/packages/security/example/rate_limit_redis.dart b/packages/security/example/rate_limit_redis.dart
new file mode 100644
index 00000000..40d9c33b
--- /dev/null
+++ b/packages/security/example/rate_limit_redis.dart
@@ -0,0 +1,39 @@
+import 'package:angel_redis/angel_redis.dart';
+import 'package:angel_framework/angel_framework.dart';
+import 'package:angel_production/angel_production.dart';
+import 'package:angel_security/angel_security.dart';
+import 'package:resp_client/resp_client.dart';
+import 'package:resp_client/resp_commands.dart';
+
+// We run this through angel_production, so that we can have
+// multiple instances, all using the same Redis queue.
+main(List<String> args) =>
+    Runner('rate_limit_redis', configureServer).run(args);
+
+configureServer(Angel app) async {
+  // Create a simple rate limiter that limits users to 10
+  // queries per 30 seconds.
+  //
+  // In this case, we rate limit users by IP address.
+  //
+  // Our Redis store will be used to manage windows.
+  var connection = await connectSocket('localhost');
+  var client = RespClient(connection);
+  var service =
+      RedisService(RespCommands(client), prefix: 'rate_limit_redis_example');
+  var rateLimiter = ServiceRateLimiter(
+      10, Duration(seconds: 30), service, (req, res) => req.ip);
+
+  // `RateLimiter.handleRequest` is a middleware, and can be used anywhere
+  // a middleware can be used. In this case, we apply the rate limiter to
+  // *all* incoming requests.
+  app.fallback(rateLimiter.handleRequest);
+
+  // Basic routes.
+  app
+    ..get('/', (req, res) {
+      var instance = req.container.make<InstanceInfo>();
+      res.writeln('This is instance ${instance.id}.');
+    })
+    ..fallback((req, res) => throw AngelHttpException.notFound());
+}
diff --git a/packages/security/lib/angel_security.dart b/packages/security/lib/angel_security.dart
new file mode 100644
index 00000000..98a01dd1
--- /dev/null
+++ b/packages/security/lib/angel_security.dart
@@ -0,0 +1,5 @@
+export 'src/cookie_signer.dart';
+export 'src/in_memory_rate_limiter.dart';
+export 'src/rate_limiter.dart';
+export 'src/rate_limiting_window.dart';
+export 'src/service_rate_limiter.dart';
\ No newline at end of file
diff --git a/packages/security/lib/src/cookie_signer.dart b/packages/security/lib/src/cookie_signer.dart
new file mode 100644
index 00000000..4d9c81de
--- /dev/null
+++ b/packages/security/lib/src/cookie_signer.dart
@@ -0,0 +1,132 @@
+import 'dart:convert';
+import 'dart:io';
+import 'package:angel_framework/angel_framework.dart';
+import 'package:crypto/crypto.dart';
+
+/// A utility that signs, and verifies, cookies using an [Hmac].
+///
+/// It aims to mitigate so-called "cookie poisoning" attacks by
+/// ensuring that clients cannot tamper with the cookies they have been
+/// sent.
+class CookieSigner {
+  /// The [Hmac] used to sign and verify cookies.
+  final Hmac hmac;
+
+  /// Creates an [hmac] from an array of [keyBytes] and a
+  /// [hash] (defaults to [sha256]).
+  CookieSigner(List<int> keyBytes, {Hash hash})
+      : hmac = Hmac(hash ?? sha256, keyBytes);
+
+  CookieSigner.fromHmac(this.hmac);
+
+  /// Creates an [hmac] from a string [key] and a
+  /// [hash] (defaults to [sha256]).
+  factory CookieSigner.fromStringKey(String key, {Hash hash}) {
+    return CookieSigner(utf8.encode(key), hash: hash);
+  }
+
+  /// Returns a set of all the incoming cookies that had a
+  /// valid signature attached. Any cookies without a
+  /// signature, or with a signature that does not match the
+  /// provided data, are not included in the output.
+  ///
+  /// If an [onInvalidCookie] callback is passed, then it will
+  /// be invoked for each unsigned or improperly-signed cookie.
+  List<Cookie> readCookies(RequestContext req,
+      {void Function(Cookie) onInvalidCookie}) {
+    return req.cookies.fold([], (out, cookie) {
+      var data = getCookiePayloadAndSignature(cookie.value);
+      if (data == null || (data[1] != computeCookieSignature(data[0]))) {
+        if (onInvalidCookie != null) {
+          onInvalidCookie(cookie);
+        }
+        return out;
+      } else {
+        return out..add(cookieWithNewValue(cookie, data[0]));
+      }
+    });
+  }
+
+  /// Determines whether a cookie is properly signed,
+  /// if it is signed at all.
+  ///
+  /// If there is no signature, returns `false`.
+  /// If the provided signature does not match the payload
+  /// provided, returns `false`.
+  /// Otherwise, returns true.
+  bool verify(Cookie cookie) {
+    var data = getCookiePayloadAndSignature(cookie.value);
+    return (data != null && (data[1] == computeCookieSignature(data[0])));
+  }
+
+  /// Gets the payload and signature of a given [cookie], WITHOUT
+  /// verifying its integrity.
+  ///
+  /// Returns `null` if no payload can be found.
+  /// Otherwise, returns a list with a length of 2, where
+  /// the item at index `0` is the payload, and the item at
+  /// index `1` is the signature.
+  List<String> getCookiePayloadAndSignature(String cookieValue) {
+    var dot = cookieValue.indexOf('.');
+    if (dot <= 0) {
+      return null;
+    } else if (dot >= cookieValue.length - 1) {
+      return null;
+    } else {
+      var payload = cookieValue.substring(0, dot);
+      var sig = cookieValue.substring(dot + 1);
+      return [payload, sig];
+    }
+  }
+
+  /// Signs a single [cookie], and adds it to an outgoing
+  /// [res]ponse. The input [cookie] is not modified.
+  ///
+  /// See [createSignedCookie].
+  void writeCookie(ResponseContext res, Cookie cookie) {
+    res.cookies.add(createSignedCookie(cookie));
+  }
+
+  /// Signs a set of [cookies], and adds them to an outgoing
+  /// [res]ponse. The input [cookies] are not modified.
+  ///
+  /// See [createSignedCookie].
+  void writeCookies(ResponseContext res, Iterable<Cookie> cookies) {
+    cookies.forEach((c) => writeCookie(res, c));
+  }
+
+  /// Returns a new cookie, replacing the value of an input
+  /// [cookie] with one that is signed with the [hmac].
+  ///
+  /// The new value is:
+  /// `cookie.value + "." + base64Url(sig)`
+  ///
+  /// Where `sig` is the cookie's value, signed with the [hmac].
+  Cookie createSignedCookie(Cookie cookie) {
+    return cookieWithNewValue(
+        cookie, cookie.value + '.' + computeCookieSignature(cookie.value));
+  }
+
+  /// Returns a new [Cookie] that is the same as the input
+  /// [cookie], but with a [newValue].
+  Cookie cookieWithNewValue(Cookie cookie, String newValue) {
+    return Cookie(cookie.name, newValue)
+      ..domain = cookie.domain
+      ..expires = cookie.expires
+      ..httpOnly = cookie.httpOnly
+      ..maxAge = cookie.maxAge
+      ..path = cookie.path
+      ..secure = cookie.secure;
+  }
+
+  /// Computes the *signature* of a [cookieValue], either for
+  /// signing an outgoing cookie, or verifying an incoming cookie.
+  String computeCookieSignature(String cookieValue) {
+    // base64Url(cookie) + "." + base64Url(sig)
+    // var encodedCookie = base64Url.encode(cookieValue.codeUnits);
+    var sigBytes = hmac.convert(cookieValue.codeUnits).bytes;
+    return base64Url.encode(sigBytes);
+    // var sig = base64Url.encode(sigBytes);
+    // return encodedCookie + '.' + sig;
+  }
+}
diff --git a/packages/security/lib/src/csrf_filter.dart b/packages/security/lib/src/csrf_filter.dart
new file mode 100644
index 00000000..df0e8938
--- /dev/null
+++ b/packages/security/lib/src/csrf_filter.dart
@@ -0,0 +1,19 @@
+import 'dart:async';
+import 'package:angel_framework/angel_framework.dart';
+import 'cookie_signer.dart';
+
+class CsrfToken {
+  final String value;
+
+  CsrfToken(this.value);
+}
+
+class CsrfFilter {
+  final CookieSigner cookieSigner;
+
+  CsrfFilter(this.cookieSigner);
+
+  Future<CsrfToken> readCsrfToken(RequestContext req) async {
+    
+  }
+}
diff --git a/packages/security/lib/src/helmet.dart b/packages/security/lib/src/helmet.dart
new file mode 100644
index 00000000..7cababd9
--- /dev/null
+++ b/packages/security/lib/src/helmet.dart
@@ -0,0 +1,5 @@
+import 'package:angel_framework/angel_framework.dart';
+
+class Helmet {
+  
+}
\ No newline at end of file
diff --git a/packages/security/lib/src/in_memory_rate_limiter.dart b/packages/security/lib/src/in_memory_rate_limiter.dart
new file mode 100644
index 00000000..d545b8b6
--- /dev/null
+++ b/packages/security/lib/src/in_memory_rate_limiter.dart
@@ -0,0 +1,30 @@
+import 'dart:async';
+import 'package:angel_framework/angel_framework.dart';
+import 'rate_limiter.dart';
+import 'rate_limiting_window.dart';
+
+/// A simple [RateLimiter] implementation that uses a simple in-memory map
+/// to store rate limiting information.
+class InMemoryRateLimiter<User> extends RateLimiter<User> {
+  /// A callback used to compute the current user.
+  final FutureOr<User> Function(RequestContext, ResponseContext) getUser;
+  final _cache = <User, RateLimitingWindow<User>>{};
+
+  InMemoryRateLimiter(
+      int maxPointsPerWindow, Duration windowDuration, this.getUser,
+      {String errorMessage})
+      : super(maxPointsPerWindow, windowDuration, errorMessage: errorMessage);
+
+  @override
+  FutureOr<RateLimitingWindow<User>> getCurrentWindow(
+      RequestContext req, ResponseContext res, DateTime currentTime) async {
+    var user = await getUser(req, res);
+    return _cache[user] ??= RateLimitingWindow(user, currentTime, 0);
+  }
+
+  @override
+  FutureOr<void> updateCurrentWindow(RequestContext req, ResponseContext res,
+      RateLimitingWindow<User> window, DateTime currentTime) {
+    _cache[window.user] = window;
+  }
+}
diff --git a/packages/security/lib/src/rate_limiter.dart b/packages/security/lib/src/rate_limiter.dart
new file mode 100644
index 00000000..fb8b99cd
--- /dev/null
+++ b/packages/security/lib/src/rate_limiter.dart
@@ -0,0 +1,156 @@
+import 'dart:async';
+import 'package:angel_framework/angel_framework.dart';
+import 'package:angel_security/angel_security.dart';
+import 'rate_limiting_window.dart';
+
+/// A base class that facilitates rate limiting API's or endpoints,
+/// typically to prevent spam and abuse.
+///
+/// The rate limiter operates under the assumption that a [User] object
+/// can be computed from each request, as well as information about
+/// the current rate-limiting window.
+abstract class RateLimiter<User> {
+  /// The maximum number of points that may be consumed
+  /// within the given [windowDuration].
+  final int maxPointsPerWindow;
+
+  /// The amount of time, during which, a user is not allowed to consume
+  /// more than [maxPointsPerWindow].
+  final Duration windowDuration;
+
+  /// The error message to send to a [User] who has exceeded the
+  /// rate limit during the current window.
+  ///
+  /// This only applies to the default implementation of
+  /// [rejectRequest].
+  final String errorMessage;
+
+  RateLimiter(this.maxPointsPerWindow, this.windowDuration,
+      {String errorMessage})
+      : this.errorMessage = errorMessage ?? 'Rate limit exceeded.';
+
+  /// Computes the current window in which the user is acting.
+  ///
+  /// For example, if your API was limited to 1000 requests/hour,
+  /// then you would return a window containing the current hour,
+  /// and the number of requests the user has sent in the past hour.
+  FutureOr<RateLimitingWindow<User>> getCurrentWindow(
+      RequestContext req, ResponseContext res, DateTime currentTime);
+
+  /// Updates the underlying store with information about the new
+  /// [window] that the user is operating in.
+  FutureOr<void> updateCurrentWindow(RequestContext req, ResponseContext res,
+      RateLimitingWindow<User> window, DateTime currentTime);
+
+  /// Computes the amount of points that a given request will cost. This amount
+  /// is then added to the amount of points that the user has already consumed
+  /// in the current [window].
+  ///
+  /// The default behavior is to return `1`, which signifies that all requests
+  /// carry the same weight.
+  FutureOr<int> getEndpointCost(RequestContext req, ResponseContext res,
+      RateLimitingWindow<User> window) {
+    return Future<int>.value(1);
+  }
+
+  /// Alerts the user of information pertinent to the current [window].
+  ///
+  /// The default implementation is to send the following headers, akin to
+  /// Github's v4 Graph API:
+  /// * `X-RateLimit-Limit`: The maximum number of points consumed per window.
+  /// * `X-RateLimit-Remaining`: The remaining number of points that may be consumed
+  /// before the rate limit is reached for the current window.
+  /// * `X-RateLimit-Reset`: The Unix timestamp, at which the window will
+  /// reset.
+  FutureOr<void> sendWindowInformation(RequestContext req, ResponseContext res,
+      RateLimitingWindow<User> window) {
+    res.headers.addAll({
+      'x-ratelimit-limit': window.pointLimit.toString(),
+      'x-ratelimit-remaining': window.remainingPoints.toString(),
+      'x-ratelimit-reset':
+          (window.resetTime.millisecondsSinceEpoch ~/ 1000).toString(),
+    });
+  }
+
+  /// Signals to a user that they have exceeded the rate limit for the
+  /// current window, and terminates execution of the current [RequestContext].
+  ///
+  /// The default implementation is throw an [AngelHttpException] with
+  /// status code `429` and the given `errorMessage`, as well as sending
+  /// a [`Retry-After`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/429)
+  /// header, and then returning `false`.
+  ///
+  /// Whatever is returned here will be returned in [handleRequest].
+  FutureOr<Object> rejectRequest(RequestContext req, ResponseContext res,
+      RateLimitingWindow<User> window, DateTime currentTime) {
+    var retryAfter = window.resetTime.difference(currentTime);
+    res.headers['retry-after'] = retryAfter.inSeconds.toString();
+    throw AngelHttpException(null, message: errorMessage, statusCode: 429);
+  }
+
+  /// A request middleware that returns `true` if the user has not yet
+  /// exceeded the [maxPointsPerWindow].
+  ///
+  /// Because this handler is typically called *before* business logic is
+  /// executed, it technically checks whether the *previous* call raised the
+  /// number of consumed points to greater than, or equal to, the
+  /// [maxPointsPerWindow].
+  Future handleRequest(RequestContext req, ResponseContext res) async {
+    // Obtain information about the current window.
+    var now = DateTime.now().toUtc();
+    var currentWindow = await getCurrentWindow(req, res, now);
+    // Check if the rate limit has been exceeded. If so, reject the request.
+    // To perform this check, we must first determine whether a new window
+    // has begun since the previous request.
+    var currentWindowEnd = currentWindow.startTime.toUtc().add(windowDuration);
+    // We must also compute the missing information about the current window,
+    // so that we can relay that information to the client.
+    var remainingPoints = maxPointsPerWindow - currentWindow.pointsConsumed;
+    currentWindow
+      ..pointLimit = maxPointsPerWindow
+      ..remainingPoints = remainingPoints < 0 ? 0 : remainingPoints
+      ..resetTime = currentWindow.startTime.add(windowDuration);
+
+    // If the previous window ended in the past, begin a new window.
+    if (now.compareTo(currentWindowEnd) >= 0) {
+      // Create a new window.
+      var cost = await getEndpointCost(req, res, currentWindow);
+      var remainingPoints = maxPointsPerWindow - cost;
+      var newWindow = RateLimitingWindow(currentWindow.user, now, cost)
+        ..pointLimit = maxPointsPerWindow
+        ..remainingPoints = remainingPoints < 0 ? 0 : remainingPoints
+        ..resetTime = now.add(windowDuration);
+      await updateCurrentWindow(req, res, newWindow, now);
+      await sendWindowInformation(req, res, newWindow);
+    }
+
+    // If we are still within the previous window, check if the user has
+    // exceeded the rate limit.
+    //
+    // Otherwise, update the current window.
+    //
+    // At this point in the computation,
+    // we are still only considering whether the *previous* request took the
+    // user over the rate limit.
+    else if (currentWindow.pointsConsumed >= maxPointsPerWindow) {
+      await sendWindowInformation(req, res, currentWindow);
+      var result = await rejectRequest(req, res, currentWindow, now);
+      if (result != null) return result;
+      return false;
+    } else {
+      // Add the cost of the current endpoint, and update the window.
+      var cost = await getEndpointCost(req, res, currentWindow);
+      currentWindow
+        ..pointsConsumed += cost
+        ..remainingPoints -= cost;
+      if (currentWindow.remainingPoints < 0) {
+        currentWindow.remainingPoints = 0;
+      }
+      await updateCurrentWindow(req, res, currentWindow, now);
+      await sendWindowInformation(req, res, currentWindow);
+    }
+
+    // Pass through, so other handlers can be executed.
+    return true;
+  }
+}
diff --git a/packages/security/lib/src/rate_limiting_window.dart b/packages/security/lib/src/rate_limiting_window.dart
new file mode 100644
index 00000000..07fff1b1
--- /dev/null
+++ b/packages/security/lib/src/rate_limiting_window.dart
@@ -0,0 +1,50 @@
+/// A representation of the abstract "rate-limiting window" in which
+/// a [user] is accessing some API or endpoint.
+class RateLimitingWindow<User> {
+  /// The user who is accessing the endpoint.
+  User user;
+
+  /// The time at which the user's current window began.
+  DateTime startTime;
+
+  /// The number of points the user has already consumed within
+  /// the current window.
+  int pointsConsumed;
+
+  /// The maximum amount of points allowed within a single window.
+  ///
+  /// This field is typically only set by the [RateLimiter] middleware,
+  /// and is therefore optional in the constructor.
+  int pointLimit;
+
+  /// The amount of points the user can consume before hitting the
+  /// rate limit for the current window.
+  ///
+  /// This field is typically only set by the [RateLimiter] middleware,
+  /// and is therefore optional in the constructor.
+  int remainingPoints;
+
+  /// The time at which the window will reset.
+  ///
+  /// This field is typically only set by the [RateLimiter] middleware,
+  /// and is therefore optional in the constructor.
+  DateTime resetTime;
+
+  RateLimitingWindow(this.user, this.startTime, this.pointsConsumed,
+      {this.pointLimit, this.remainingPoints, this.resetTime});
+
+  factory RateLimitingWindow.fromJson(Map<String, dynamic> map) {
+    return RateLimitingWindow(
+        map['user'] as User,
+        DateTime.parse(map['start_time'] as String),
+        int.parse(map['points_consumed'] as String));
+  }
+
+  Map<String, dynamic> toJson() {
+    return {
+      'user': user,
+      'start_time': startTime.toIso8601String(),
+      'points_consumed': pointsConsumed.toString(),
+    };
+  }
+}
diff --git a/packages/security/lib/src/service_rate_limiter.dart b/packages/security/lib/src/service_rate_limiter.dart
new file mode 100644
index 00000000..f3bb1e4f
--- /dev/null
+++ b/packages/security/lib/src/service_rate_limiter.dart
@@ -0,0 +1,50 @@
+import 'dart:async';
+import 'package:angel_framework/angel_framework.dart';
+import 'rate_limiter.dart';
+import 'rate_limiting_window.dart';
+
+/// A RateLimiter] implementation that uses a [Service]
+/// to store rate limiting information.
+class ServiceRateLimiter<Id> extends RateLimiter<Id> {
+  /// The underlying [Service] used to store data.
+  final Service<Id, Map<String, dynamic>> service;
+
+  /// A callback used to compute the current user ID.
+  final FutureOr<Id> Function(RequestContext, ResponseContext) getId;
+
+  ServiceRateLimiter(
+      int maxPointsPerWindow, Duration windowDuration, this.service, this.getId,
+      {String errorMessage})
+      : super(maxPointsPerWindow, windowDuration, errorMessage: errorMessage);
+
+  @override
+  FutureOr<RateLimitingWindow<Id>> getCurrentWindow(
+      RequestContext req, ResponseContext res, DateTime currentTime) async {
+    var id = await getId(req, res);
+    try {
+      var data = await service.read(id);
+      if (data != null) {
+        return RateLimitingWindow.fromJson(data);
+      }
+    } catch (e) {
+      if (e is AngelHttpException) {
+        if (e.statusCode == 404) {
+        } else {
+          rethrow;
+        }
+      } else {
+        rethrow;
+      }
+    }
+
+    var window = RateLimitingWindow(id, currentTime, 0);
+    await updateCurrentWindow(req, res, window, currentTime);
+    return window;
+  }
+
+  @override
+  FutureOr<void> updateCurrentWindow(RequestContext req, ResponseContext res,
+      RateLimitingWindow<Id> window, DateTime currentTime) async {
+    await service.update(window.user, window.toJson());
+  }
+}
diff --git a/packages/security/pubspec.yaml b/packages/security/pubspec.yaml
new file mode 100644
index 00000000..5211f6aa
--- /dev/null
+++ b/packages/security/pubspec.yaml
@@ -0,0 +1,19 @@
+name: angel_security
+version: 2.0.0-alpha.1
+description: Angel infrastructure for improving security, rate limiting, and more.
+author: Tobe O <thosakwe@gmail.com>
+homepage: https://github.com/angel-dart/security
+environment: 
+  sdk: ">=2.0.0-dev <3.0.0"
+dependencies: 
+  angel_framework: ^2.0.0
+  crypto: ^2.0.0
+dev_dependencies: 
+  angel_auth: ^2.0.0
+  angel_production: ^1.0.0
+  angel_redis: ^1.0.0
+  angel_test: ^2.0.0
+  angel_validate: ^2.0.0
+  pedantic: ^1.0.0
+  pretty_logging: ^1.0.0
+  test: ^1.0.0
diff --git a/packages/security/test/all_test.dart b/packages/security/test/all_test.dart
new file mode 100644
index 00000000..54b7b267
--- /dev/null
+++ b/packages/security/test/all_test.dart
@@ -0,0 +1,3 @@
+import 'package:test/test.dart';
+
+void main() {}