diff --git a/lib/zip/crypto/null_encryption.rb b/lib/zip/crypto/null_encryption.rb
index 37e03ede..38dafa8f 100644
--- a/lib/zip/crypto/null_encryption.rb
+++ b/lib/zip/crypto/null_encryption.rb
@@ -12,7 +12,7 @@ def gp_flags
   class NullEncrypter < Encrypter
     include NullEncryption
 
-    def header(crc32)
+    def header(mtime)
       ''
     end
 
@@ -20,6 +20,10 @@ def encrypt(data)
       data
     end
 
+    def data_descriptor(crc32, compressed_size, uncomprssed_size)
+      ''
+    end
+
     def reset!
     end
   end
diff --git a/lib/zip/crypto/traditional_encryption.rb b/lib/zip/crypto/traditional_encryption.rb
index 163bf5b6..b57541a9 100644
--- a/lib/zip/crypto/traditional_encryption.rb
+++ b/lib/zip/crypto/traditional_encryption.rb
@@ -10,7 +10,7 @@ def header_bytesize
     end
 
     def gp_flags
-      1
+      0x0001 | 0x0008
     end
 
     protected
@@ -39,12 +39,13 @@ def decrypt_byte
   class TraditionalEncrypter < Encrypter
     include TraditionalEncryption
 
-    def header(crc32)
+    def header(mtime)
       [].tap do |header|
-        (header_bytesize - 1).times do
+        (header_bytesize - 2).times do
           header << Random.rand(0..255)
         end
-        header << (crc32 >> 24)
+        header << (mtime.to_binary_dos_time & 0xff)
+        header << (mtime.to_binary_dos_time >> 8)
       end.map{|x| encode x}.pack("C*")
     end
 
@@ -52,6 +53,10 @@ def encrypt(data)
       data.unpack("C*").map{|x| encode x}.pack("C*")
     end
 
+    def data_descriptor(crc32, compressed_size, uncomprssed_size)
+      [0x08074b50, crc32, compressed_size, uncomprssed_size].pack("VVVV")
+    end
+
     def reset!
       reset_keys!
     end
diff --git a/lib/zip/deflater.rb b/lib/zip/deflater.rb
index d4340589..ffcebb64 100755
--- a/lib/zip/deflater.rb
+++ b/lib/zip/deflater.rb
@@ -5,7 +5,7 @@ def initialize(output_stream, level = Zip.default_compression, encrypter = NullE
       super()
       @output_stream = output_stream
       @zlib_deflater = ::Zlib::Deflate.new(level, -::Zlib::MAX_WBITS)
-      @size          = encrypter.header_bytesize
+      @size          = 0
       @crc           = ::Zlib.crc32
       @encrypter     = encrypter
       @buffer_stream = ::StringIO.new('')
@@ -19,7 +19,6 @@ def << (data)
     end
 
     def finish
-      @output_stream << @encrypter.header(@crc)
       @output_stream << @encrypter.encrypt(@buffer_stream.string)
       @output_stream << @encrypter.encrypt(@zlib_deflater.finish) until @zlib_deflater.finished?
     end
diff --git a/lib/zip/entry.rb b/lib/zip/entry.rb
index 281bd8fa..05ca23b4 100755
--- a/lib/zip/entry.rb
+++ b/lib/zip/entry.rb
@@ -143,7 +143,7 @@ def cdir_header_size #:nodoc:all
     end
 
     def next_header_offset #:nodoc:all
-      local_entry_offset + self.compressed_size
+      local_entry_offset + self.compressed_size + data_descriptor_size
     end
 
     # Extracts entry to file dest_path (defaults to @name).
@@ -648,6 +648,10 @@ def parse_zip64_extra(for_local_header) #:nodoc:all
       end
     end
 
+    def data_descriptor_size
+      (@gp_flags & 0x0008) > 0 ? 16 : 0
+    end
+
     # create a zip64 extra information field if we need one
     def prep_zip64_extra(for_local_header) #:nodoc:all
       return unless ::Zip.write_zip64_support
diff --git a/lib/zip/output_stream.rb b/lib/zip/output_stream.rb
index f28e5759..e9c54731 100755
--- a/lib/zip/output_stream.rb
+++ b/lib/zip/output_stream.rb
@@ -123,10 +123,12 @@ def copy_raw_entry(entry)
 
     def finalize_current_entry
       return unless @current_entry
+      @output_stream << @encrypter.header(@current_entry.mtime)
       finish
       @current_entry.compressed_size = @output_stream.tell - @current_entry.local_header_offset - @current_entry.calculate_local_header_size
       @current_entry.size = @compressor.size
       @current_entry.crc = @compressor.crc
+      @output_stream << @encrypter.data_descriptor(@current_entry.crc, @current_entry.compressed_size, @current_entry.size)
       @current_entry.gp_flags |= @encrypter.gp_flags
       @current_entry = nil
       @compressor = ::Zip::NullCompressor.instance
diff --git a/test/crypto/null_encryption_test.rb b/test/crypto/null_encryption_test.rb
index fa54b025..b9452a03 100644
--- a/test/crypto/null_encryption_test.rb
+++ b/test/crypto/null_encryption_test.rb
@@ -14,9 +14,7 @@ def test_gp_flags
   end
 
   def test_header
-    [nil, '', 'a' * 10, 0xffffffff].each do |arg|
-      assert_empty @encrypter.header(arg)
-    end
+    assert_empty @encrypter.header(nil)
   end
 
   def test_encrypt
diff --git a/test/crypto/traditional_encryption_test.rb b/test/crypto/traditional_encryption_test.rb
index fb1e4ff1..3e743946 100644
--- a/test/crypto/traditional_encryption_test.rb
+++ b/test/crypto/traditional_encryption_test.rb
@@ -2,6 +2,7 @@
 
 class TraditionalEncrypterTest < MiniTest::Test
   def setup
+    @mtime = ::Zip::DOSTime.new(2014, 12, 17, 15, 56, 24)
     @encrypter = ::Zip::TraditionalEncrypter.new('password')
   end
 
@@ -10,36 +11,36 @@ def test_header_bytesize
   end
 
   def test_gp_flags
-    assert_equal 1, @encrypter.gp_flags
+    assert_equal 9, @encrypter.gp_flags
   end
 
   def test_header
     @encrypter.reset!
-    exepected = [239, 57, 234, 154, 246, 80, 83, 221, 74, 200, 116, 154].pack("C*")
+    exepected = [239, 57, 234, 154, 246, 80, 83, 221, 74, 200, 121, 91].pack("C*")
     Random.stub(:rand, 1) do
-      assert_equal exepected, @encrypter.header(0xffffffff)
+      assert_equal exepected, @encrypter.header(@mtime)
     end
   end
 
   def test_encrypt
     @encrypter.reset!
-    Random.stub(:rand, 1) { @encrypter.header(0xffffffff) }
+    Random.stub(:rand, 1) { @encrypter.header(@mtime) }
     assert_raises(NoMethodError) { @encrypter.encrypt(nil) }
     assert_raises(NoMethodError) { @encrypter.encrypt(1) }
     assert_equal '', @encrypter.encrypt('')
-    assert_equal [2, 25, 13, 222, 17, 190, 250, 133, 133, 166].pack("C*"), @encrypter.encrypt('a' * 10)
+    assert_equal [100, 218, 7, 114, 226, 82, 62, 93, 224, 62].pack("C*"), @encrypter.encrypt('a' * 10)
   end
 
   def test_reset!
     @encrypter.reset!
-    Random.stub(:rand, 1) { @encrypter.header(0xffffffff) }
-    [2, 25, 13, 222, 17, 190, 250, 133, 133, 166].map(&:chr).each do |c|
+    Random.stub(:rand, 1) { @encrypter.header(@mtime) }
+    [100, 218, 7, 114, 226, 82, 62, 93, 224, 62].map(&:chr).each do |c|
       assert_equal c, @encrypter.encrypt('a')
     end
-    assert_equal 134.chr, @encrypter.encrypt('a')
+    assert_equal 56.chr, @encrypter.encrypt('a')
     @encrypter.reset!
-    Random.stub(:rand, 1) { @encrypter.header(0xffffffff) }
-    [2, 25, 13, 222, 17, 190, 250, 133, 133, 166].map(&:chr).each do |c|
+    Random.stub(:rand, 1) { @encrypter.header(@mtime) }
+    [100, 218, 7, 114, 226, 82, 62, 93, 224, 62].map(&:chr).each do |c|
       assert_equal c, @encrypter.encrypt('a')
     end
   end
@@ -55,24 +56,24 @@ def test_header_bytesize
   end
 
   def test_gp_flags
-    assert_equal 1, @decrypter.gp_flags
+    assert_equal 9, @decrypter.gp_flags
   end
 
   def test_decrypt
-    @decrypter.reset!([239, 57, 234, 154, 246, 80, 83, 221, 74, 200, 116, 154].pack("C*"))
-    [2, 25, 13, 222, 17, 190, 250, 133, 133, 166].map(&:chr).each do |c|
+    @decrypter.reset!([239, 57, 234, 154, 246, 80, 83, 221, 74, 200, 121, 91].pack("C*"))
+    [100, 218, 7, 114, 226, 82, 62, 93, 224, 62].map(&:chr).each do |c|
       assert_equal 'a', @decrypter.decrypt(c)
     end
   end
 
   def test_reset!
-    @decrypter.reset!([239, 57, 234, 154, 246, 80, 83, 221, 74, 200, 116, 154].pack("C*"))
-    [2, 25, 13, 222, 17, 190, 250, 133, 133, 166].map(&:chr).each do |c|
+    @decrypter.reset!([239, 57, 234, 154, 246, 80, 83, 221, 74, 200, 121, 91].pack("C*"))
+    [100, 218, 7, 114, 226, 82, 62, 93, 224, 62].map(&:chr).each do |c|
       assert_equal 'a', @decrypter.decrypt(c)
     end
-    assert_equal 229.chr, @decrypter.decrypt(2.chr)
-    @decrypter.reset!([239, 57, 234, 154, 246, 80, 83, 221, 74, 200, 116, 154].pack("C*"))
-    [2, 25, 13, 222, 17, 190, 250, 133, 133, 166].map(&:chr).each do |c|
+    assert_equal 91.chr, @decrypter.decrypt(2.chr)
+    @decrypter.reset!([239, 57, 234, 154, 246, 80, 83, 221, 74, 200, 121, 91].pack("C*"))
+    [100, 218, 7, 114, 226, 82, 62, 93, 224, 62].map(&:chr).each do |c|
       assert_equal 'a', @decrypter.decrypt(c)
     end
   end
diff --git a/test/data/zipWithEncryption.zip b/test/data/zipWithEncryption.zip
new file mode 100644
index 00000000..e102b875
Binary files /dev/null and b/test/data/zipWithEncryption.zip differ
diff --git a/test/encryption_test.rb b/test/encryption_test.rb
new file mode 100644
index 00000000..32b367cd
--- /dev/null
+++ b/test/encryption_test.rb
@@ -0,0 +1,33 @@
+require 'test_helper'
+
+class EncryptionTest < MiniTest::Test
+  ENCRYPT_ZIP_TEST_FILE = 'test/data/zipWithEncryption.zip'
+  INPUT_FILE1 = 'test/data/file1.txt'
+
+  def test_encrypt
+    test_file = open(ENCRYPT_ZIP_TEST_FILE, 'rb').read
+
+    @rand = [250, 143, 107, 13, 143, 22, 155, 75, 228, 150, 12]
+    @output = ::Zip::DOSTime.stub(:now, ::Zip::DOSTime.new(2014, 12, 17, 15, 56, 24)) do
+      Random.stub(:rand, lambda { |range| @rand.shift }) do
+        Zip::OutputStream.write_buffer(::StringIO.new(''), Zip::TraditionalEncrypter.new('password')) do |zos|
+          zos.put_next_entry('file1.txt')
+          zos.write open(INPUT_FILE1).read
+        end.string
+      end
+    end
+
+    @output.unpack("C*").each_with_index do |c, i|
+      assert_equal test_file[i].ord, c
+    end
+  end
+
+  def test_decrypt
+    Zip::InputStream.open(ENCRYPT_ZIP_TEST_FILE, 0, Zip::TraditionalDecrypter.new('password')) do |zis|
+      entry = zis.get_next_entry
+      assert_equal 'file1.txt', entry.name
+      assert_equal 1327, entry.size
+      assert_equal open(INPUT_FILE1, 'r').read, zis.read
+    end
+  end
+end