diff --git a/actionpack/lib/action_controller.rb b/actionpack/lib/action_controller.rb
index 8c1f548e47..e76dc954d9 100644
--- a/actionpack/lib/action_controller.rb
+++ b/actionpack/lib/action_controller.rb
@@ -34,6 +34,7 @@ module ActionController
     autoload :Rescue
     autoload :Responder
     autoload :Streaming
+    autoload :StrongParameters
     autoload :Testing
     autoload :UrlFor
   end
diff --git a/actionpack/lib/action_controller/base.rb b/actionpack/lib/action_controller/base.rb
index f829f5e8a2..d799107a14 100644
--- a/actionpack/lib/action_controller/base.rb
+++ b/actionpack/lib/action_controller/base.rb
@@ -196,6 +196,7 @@ module ActionController
       Caching,
       MimeResponds,
       ImplicitRender,
+      StrongParameters,
 
       Cookies,
       Flash,
diff --git a/actionpack/lib/action_controller/metal/strong_parameters.rb b/actionpack/lib/action_controller/metal/strong_parameters.rb
new file mode 100644
index 0000000000..b027901f28
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/strong_parameters.rb
@@ -0,0 +1,120 @@
+require 'active_support/concern'
+require 'active_support/core_ext/hash/indifferent_access'
+require 'active_support/rescuable'
+
+module ActionController
+  class ParameterMissing < IndexError
+    attr_reader :param
+
+    def initialize(param)
+      @param = param
+      super("key not found: #{param}")
+    end
+  end
+
+  class Parameters < ActiveSupport::HashWithIndifferentAccess
+    attr_accessor :permitted
+    alias :permitted? :permitted
+
+    def initialize(attributes = nil)
+      super(attributes)
+      @permitted = false
+    end
+
+    def permit!
+      @permitted = true
+      self
+    end
+
+    def require(key)
+      self[key].presence || raise(ParameterMissing.new(key))
+    end
+
+    alias :required :require
+
+    def permit(*filters)
+      params = self.class.new
+
+      filters.each do |filter|
+        case filter
+        when Symbol, String then
+          params[filter] = self[filter] if has_key?(filter)
+        when Hash then
+          self.slice(*filter.keys).each do |key, value|
+            return unless value
+
+            key = key.to_sym
+
+            params[key] = each_element(value) do |value|
+              # filters are a Hash, so we expect value to be a Hash too
+              next if filter.is_a?(Hash) && !value.is_a?(Hash)
+
+              value = self.class.new(value) if !value.respond_to?(:permit)
+
+              value.permit(*Array.wrap(filter[key]))
+            end
+          end
+        end
+      end
+
+      params.permit!
+    end
+
+    def [](key)
+      convert_hashes_to_parameters(key, super)
+    end
+
+    def fetch(key, *args)
+      convert_hashes_to_parameters(key, super)
+    rescue KeyError
+      raise ActionController::ParameterMissing.new(key)
+    end
+
+    def slice(*keys)
+      self.class.new(super)
+    end
+
+    def dup
+      super.tap do |duplicate|
+        duplicate.instance_variable_set :@permitted, @permitted
+      end
+    end
+
+    private
+      def convert_hashes_to_parameters(key, value)
+        if value.is_a?(Parameters) || !value.is_a?(Hash)
+          value
+        else
+          # Convert to Parameters on first access
+          self[key] = self.class.new(value)
+        end
+      end
+
+      def each_element(object)
+        if object.is_a?(Array)
+          object.map { |el| yield el }.compact
+        else
+          yield object
+        end
+      end
+  end
+
+  module StrongParameters
+    extend ActiveSupport::Concern
+    include ActiveSupport::Rescuable
+
+    included do
+      rescue_from(ActionController::ParameterMissing) do |parameter_missing_exception|
+        render text: "Required parameter missing: #{parameter_missing_exception.param}", status: :bad_request
+      end
+    end
+
+    def params
+      @_params ||= Parameters.new(request.parameters)
+    end
+
+    def params=(val)
+      @_params = val.is_a?(Hash) ? Parameters.new(val) : val
+    end
+  end
+end
diff --git a/actionpack/test/controller/parameters/nested_parameters_test.rb b/actionpack/test/controller/parameters/nested_parameters_test.rb
new file mode 100644
index 0000000000..00a682a273
--- /dev/null
+++ b/actionpack/test/controller/parameters/nested_parameters_test.rb
@@ -0,0 +1,94 @@
+require 'action_controller/metal/strong_parameters'
+
+class NestedParametersTest < ActiveSupport::TestCase
+  test "permitted nested parameters" do
+    params = ActionController::Parameters.new({
+      book: {
+        title: "Romeo and Juliet",
+        authors: [{
+          name: "William Shakespeare",
+          born: "1564-04-26"
+        }, {
+          name: "Christopher Marlowe"
+        }],
+        details: {
+          pages: 200,
+          genre: "Tragedy"
+        }
+      },
+      magazine: "Mjallo!"
+    })
+
+    permitted = params.permit book: [ :title, { authors: [ :name ] }, { details: :pages } ]
+
+    assert permitted.permitted?
+    assert_equal "Romeo and Juliet", permitted[:book][:title]
+    assert_equal "William Shakespeare", permitted[:book][:authors][0][:name]
+    assert_equal "Christopher Marlowe", permitted[:book][:authors][1][:name]
+    assert_equal 200, permitted[:book][:details][:pages]
+    assert_nil permitted[:book][:details][:genre]
+    assert_nil permitted[:book][:authors][1][:born]
+    assert_nil permitted[:magazine]
+  end
+
+  test "nested arrays with strings" do
+    params = ActionController::Parameters.new({
+      :book => {
+        :genres => ["Tragedy"]
+      }
+    })
+
+    permitted = params.permit :book => :genres
+    assert_equal ["Tragedy"], permitted[:book][:genres]
+  end
+
+  test "permit may specify symbols or strings" do
+    params = ActionController::Parameters.new({
+      :book => {
+        :title => "Romeo and Juliet",
+        :author => "William Shakespeare"
+      },
+      :magazine => "Shakespeare Today"
+    })
+
+    permitted = params.permit({:book => ["title", :author]}, "magazine")
+    assert_equal "Romeo and Juliet", permitted[:book][:title]
+    assert_equal "William Shakespeare", permitted[:book][:author]
+    assert_equal "Shakespeare Today", permitted[:magazine]
+  end
+
+  test "nested array with strings that should be hashes" do
+    params = ActionController::Parameters.new({
+      book: {
+        genres: ["Tragedy"]
+      }
+    })
+
+    permitted = params.permit book: { genres: :type }
+    assert_empty permitted[:book][:genres]
+  end
+
+  test "nested array with strings that should be hashes and additional values" do
+    params = ActionController::Parameters.new({
+      book: {
+        title: "Romeo and Juliet",
+        genres: ["Tragedy"]
+      }
+    })
+
+    permitted = params.permit book: [ :title, { genres: :type } ]
+    assert_equal "Romeo and Juliet", permitted[:book][:title]
+    assert_empty permitted[:book][:genres]
+  end
+
+  test "nested string that should be a hash" do
+    params = ActionController::Parameters.new({
+      book: {
+        genre: "Tragedy"
+      }
+    })
+
+    permitted = params.permit book: { genre: :type }
+    assert_nil permitted[:book][:genre]
+  end
+end
diff --git a/actionpack/test/controller/parameters/parameters_require_test.rb b/actionpack/test/controller/parameters/parameters_require_test.rb
new file mode 100644
index 0000000000..5545f60d49
--- /dev/null
+++ b/actionpack/test/controller/parameters/parameters_require_test.rb
@@ -0,0 +1,9 @@
+require 'action_controller/metal/strong_parameters'
+
+class ParametersRequireTest < ActiveSupport::TestCase
+  test "required parameters must be present not merely not nil" do
+    assert_raises(ActionController::ParameterMissing) do
+      ActionController::Parameters.new(person: {}).require(:person)
+    end
+  end
+end
diff --git a/actionpack/test/controller/parameters/parameters_taint_test.rb b/actionpack/test/controller/parameters/parameters_taint_test.rb
new file mode 100644
index 0000000000..45fc368683
--- /dev/null
+++ b/actionpack/test/controller/parameters/parameters_taint_test.rb
@@ -0,0 +1,60 @@
+require 'action_controller/metal/strong_parameters'
+
+class ParametersTaintTest < ActiveSupport::TestCase
+  setup do
+    @params = ActionController::Parameters.new({ person: { 
+      age: "32", name: { first: "David", last: "Heinemeier Hansson" }
+    }})
+  end
+
+  test "fetch raises ParameterMissing exception" do
+    e = assert_raises(ActionController::ParameterMissing) do
+      @params.fetch :foo
+    end
+    assert_equal :foo, e.param
+  end
+
+  test "fetch doesnt raise ParameterMissing exception if there is a default" do
+    assert_nothing_raised do
+      assert_equal "monkey", @params.fetch(:foo, "monkey")
+      assert_equal "monkey", @params.fetch(:foo) { "monkey" }
+    end
+  end
+
+  test "permitted is sticky on accessors" do
+    assert !@params.slice(:person).permitted?
+    assert !@params[:person][:name].permitted?
+
+    @params.each { |key, value| assert(value.permitted?) if key == :person }
+
+    assert !@params.fetch(:person).permitted?
+
+    assert !@params.values_at(:person).first.permitted?
+  end
+
+  test "permitted is sticky on mutators" do
+    assert !@params.delete_if { |k| k == :person }.permitted?
+    assert !@params.keep_if { |k,v| k == :person }.permitted?
+  end
+
+  test "permitted is sticky beyond merges" do
+    assert !@params.merge(a: "b").permitted?
+  end
+
+  test "modifying the parameters" do
+    @params[:person][:hometown] = "Chicago"
+    @params[:person][:family] = { brother: "Jonas" }
+
+    assert_equal "Chicago", @params[:person][:hometown]
+    assert_equal "Jonas", @params[:person][:family][:brother]
+  end
+
+  test "permitting parameters that are not there should not include the keys" do
+    assert !@params.permit(:person, :funky).has_key?(:funky)
+  end
+
+  test "permit state is kept on a dup" do
+    @params.permit!
+    assert_equal @params.permitted?, @params.dup.permitted?
+  end
+end
diff --git a/actionpack/test/controller/required_params_test.rb b/actionpack/test/controller/required_params_test.rb
new file mode 100644
index 0000000000..661bcb3945
--- /dev/null
+++ b/actionpack/test/controller/required_params_test.rb
@@ -0,0 +1,30 @@
+require 'abstract_unit'
+
+class BooksController < ActionController::Base
+  def create
+    params.require(:book).require(:name)
+    head :ok
+  end
+end
+
+class ActionControllerRequiredParamsTest < ActionController::TestCase
+  tests BooksController
+
+  test "missing required parameters will raise exception" do
+    post :create, { magazine: { name: "Mjallo!" } }
+    assert_response :bad_request
+
+    post :create, { book: { title: "Mjallo!" } }
+    assert_response :bad_request
+  end
+
+  test "required parameters that are present will not raise" do
+    post :create, { book: { name: "Mjallo!" } }
+    assert_response :ok
+  end
+
+  test "missing parameters will be mentioned in the return" do
+    post :create, { magazine: { name: "Mjallo!" } }
+    assert_equal "Required parameter missing: book", response.body
+  end
+end
diff --git a/actionpack/test/controller/tainted_params_test.rb b/actionpack/test/controller/tainted_params_test.rb
new file mode 100644
index 0000000000..881b9d40fa
--- /dev/null
+++ b/actionpack/test/controller/tainted_params_test.rb
@@ -0,0 +1,25 @@
+require 'abstract_unit'
+
+class PeopleController < ActionController::Base
+  def create
+    render text: params[:person].permitted? ? "untainted" : "tainted"
+  end
+
+  def create_with_permit
+    render text: params[:person].permit(:name).permitted? ? "untainted" : "tainted"
+  end
+end
+
+class ActionControllerTaintedParamsTest < ActionController::TestCase
+  tests PeopleController
+
+  test "parameters are tainted" do
+    post :create, { person: { name: "Mjallo!" } }
+    assert_equal "tainted", response.body
+  end
+
+  test "parameters can be permitted and are then not tainted" do
+    post :create_with_permit, { person: { name: "Mjallo!" } }
+    assert_equal "untainted", response.body
+  end
+end