diff --git a/.gitmodules b/.gitmodules
index 2727fc7e54f..e9d24b32c73 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -17,3 +17,11 @@
 	path = external/opentk
 	url = https://github.com/mono/opentk.git
 	branch = master
+[submodule "external/libzip"]
+	path = external/libzip
+	url = https://github.com/nih-at/libzip.git
+	branch = master
+[submodule "external/LibZipSharp"]
+	path = external/LibZipSharp
+	url = https://github.com/grendello/LibZipSharp.git
+	branch = master
diff --git a/Configuration.props b/Configuration.props
index dbcad332af3..4a5e0874391 100644
--- a/Configuration.props
+++ b/Configuration.props
@@ -28,6 +28,8 @@
     <JavaInteropSourceDirectory Condition=" '$(JavaInteropSourceDirectory)' == '' ">$(MSBuildThisFileDirectory)external\Java.Interop</JavaInteropSourceDirectory>
     <MonoSourceDirectory>$(MSBuildThisFileDirectory)external\mono</MonoSourceDirectory>
     <OpenTKSourceDirectory>$(MSBuildThisFileDirectory)external\opentk</OpenTKSourceDirectory>
+    <LibZipSourceDirectory Condition=" '$(LibZipSourceDirectory)' == '' ">$(MSBuildThisFileDirectory)external\libzip</LibZipSourceDirectory>
+    <LibZipSharpSourceDirectory Condition=" '$(LibZipSharpSourceDirectory)' == '' ">$(MSBuildThisFileDirectory)external\LibZipSharp</LibZipSharpSourceDirectory>
     <SqliteSourceDirectory Condition=" '$(SqliteSourceDirectory)' == '' ">$(MSBuildThisFileDirectory)external\sqlite</SqliteSourceDirectory>
     <XamarinAndroidSourcePath>$(MSBuildThisFileDirectory)</XamarinAndroidSourcePath>
     <AllSupported32BitTargetAndroidAbis>armeabi;armeabi-v7a;x86</AllSupported32BitTargetAndroidAbis>
@@ -40,6 +42,8 @@
     <MonoSourceFullPath>$([System.IO.Path]::GetFullPath ('$(MonoSourceDirectory)'))</MonoSourceFullPath>
     <SqliteSourceFullPath>$([System.IO.Path]::GetFullPath ('$(SqliteSourceDirectory)'))</SqliteSourceFullPath>
     <OpenTKSourceFullPath>$([System.IO.Path]::GetFullPath ('$(OpenTKSourceDirectory)'))</OpenTKSourceFullPath>
+    <LibZipSourceFullPath>$([System.IO.Path]::GetFullPath ('$(LibZipSourceDirectory)'))</LibZipSourceFullPath>
+    <LibZipSharpSourceFullPath>$([System.IO.Path]::GetFullPath ('$(LibZipSharpSourceDirectory)'))</LibZipSharpSourceFullPath>
   </PropertyGroup>
   <!--
     "Fixup" $(AndroidSupportedHostJitAbis) so that Condition attributes elsewhere
diff --git a/Xamarin.Android.sln b/Xamarin.Android.sln
index dafaa6d3fbb..5908c3f6641 100644
--- a/Xamarin.Android.sln
+++ b/Xamarin.Android.sln
@@ -9,6 +9,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Xamarin.Android.Tools.Boots
 EndProject
 Project("{9344BDBB-3E7F-41FC-A0DD-8665D75EE146}") = "mono-runtimes", "build-tools\mono-runtimes\mono-runtimes.mdproj", "{C03E6CF1-7460-4CDC-A4AB-292BBC0F61F2}"
 EndProject
+Project("{9344BDBB-3E7F-41FC-A0DD-8665D75EE146}") = "libzip", "build-tools\libzip\libzip.mdproj", "{900A0F71-BAAD-417A-8D1A-8D330297CDD0}"
+EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "jnienv-gen", "build-tools\jnienv-gen\jnienv-gen.csproj", "{AFB8F6D1-6EA9-42C3-950B-98F34C669AD2}"
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "api-merge", "build-tools\api-merge\api-merge.csproj", "{3FC3E78B-F7D4-42EA-BBE8-4535DF42BFF8}"
@@ -79,6 +81,8 @@ Project("{9344BDBB-3E7F-41FC-A0DD-8665D75EE146}") = "sqlite-xamarin", "src\sqlit
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "OpenTK", "src\OpenTK-1.0\OpenTK.csproj", "{5EB9E888-E357-417E-9F39-DDEC195CE47F}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "libZipSharp", "external\LibZipSharp\libZipSharp.csproj", "{E248B2CA-303B-4645-ADDC-9D4459D550FD}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|AnyCPU = Debug|AnyCPU
@@ -358,6 +362,22 @@ Global
 		{5EB9E888-E357-417E-9F39-DDEC195CE47F}.XAIntegrationDebug|AnyCPU.Build.0 = Debug|Any CPU
 		{5EB9E888-E357-417E-9F39-DDEC195CE47F}.XAIntegrationRelease|AnyCPU.ActiveCfg = Debug|Any CPU
 		{5EB9E888-E357-417E-9F39-DDEC195CE47F}.XAIntegrationRelease|AnyCPU.Build.0 = Debug|Any CPU
+		{900A0F71-BAAD-417A-8D1A-8D330297CDD0}.Debug|AnyCPU.ActiveCfg = Debug|Any CPU
+		{900A0F71-BAAD-417A-8D1A-8D330297CDD0}.Debug|AnyCPU.Build.0 = Debug|Any CPU
+		{900A0F71-BAAD-417A-8D1A-8D330297CDD0}.Release|AnyCPU.ActiveCfg = Debug|Any CPU
+		{900A0F71-BAAD-417A-8D1A-8D330297CDD0}.Release|AnyCPU.Build.0 = Debug|Any CPU
+		{900A0F71-BAAD-417A-8D1A-8D330297CDD0}.XAIntegrationDebug|Any CPU.ActiveCfg = Debug|Any CPU
+		{900A0F71-BAAD-417A-8D1A-8D330297CDD0}.XAIntegrationDebug|Any CPU.Build.0 = Debug|Any CPU
+		{900A0F71-BAAD-417A-8D1A-8D330297CDD0}.XAIntegrationRelease|Any CPU.ActiveCfg = Debug|Any CPU
+		{900A0F71-BAAD-417A-8D1A-8D330297CDD0}.XAIntegrationRelease|Any CPU.Build.0 = Debug|Any CPU
+		{E248B2CA-303B-4645-ADDC-9D4459D550FD}.Debug|AnyCPU.ActiveCfg = Debug|Any CPU
+		{E248B2CA-303B-4645-ADDC-9D4459D550FD}.Debug|AnyCPU.Build.0 = Debug|Any CPU
+		{E248B2CA-303B-4645-ADDC-9D4459D550FD}.Release|AnyCPU.ActiveCfg = Release|Any CPU
+		{E248B2CA-303B-4645-ADDC-9D4459D550FD}.Release|AnyCPU.Build.0 = Release|Any CPU
+		{E248B2CA-303B-4645-ADDC-9D4459D550FD}.XAIntegrationDebug|Any CPU.ActiveCfg = Debug|Any CPU
+		{E248B2CA-303B-4645-ADDC-9D4459D550FD}.XAIntegrationDebug|Any CPU.Build.0 = Debug|Any CPU
+		{E248B2CA-303B-4645-ADDC-9D4459D550FD}.XAIntegrationRelease|Any CPU.ActiveCfg = Debug|Any CPU
+		{E248B2CA-303B-4645-ADDC-9D4459D550FD}.XAIntegrationRelease|Any CPU.Build.0 = Debug|Any CPU
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{8FF78EB6-6FC8-46A7-8A15-EBBA9045C5FA} = {E351F97D-EA4F-4E7F-AAA0-8EBB1F2A4A62}
@@ -395,6 +415,8 @@ Global
 		{26781D3A-FF20-4F55-9824-C8A06AA9E484} = {04E3E11E-B47D-4599-8AFC-50515A95E715}
 		{B8F799C5-D7CE-4E09-9CE6-BAA4173E7EC8} = {04E3E11E-B47D-4599-8AFC-50515A95E715}
 		{5EB9E888-E357-417E-9F39-DDEC195CE47F} = {04E3E11E-B47D-4599-8AFC-50515A95E715}
+		{900A0F71-BAAD-417A-8D1A-8D330297CDD0} = {E351F97D-EA4F-4E7F-AAA0-8EBB1F2A4A62}
+		{E248B2CA-303B-4645-ADDC-9D4459D550FD} = {04E3E11E-B47D-4599-8AFC-50515A95E715}
 	EndGlobalSection
 	GlobalSection(MonoDevelopProperties) = preSolution
 		Policies = $0
diff --git a/build-tools/android-toolchain/android-toolchain.targets b/build-tools/android-toolchain/android-toolchain.targets
index 6fe6cfb2ac8..7d2b2316d87 100644
--- a/build-tools/android-toolchain/android-toolchain.targets
+++ b/build-tools/android-toolchain/android-toolchain.targets
@@ -122,9 +122,9 @@
       DependsOnTargets="_SetMxeToolchainMakefileTimeToLastCommitTimestamp"
       Condition="$(AndroidSupportedHostJitAbisForConditionalChecks.Contains (':mxe-Win64:'))"
       Inputs="..\..\external\mxe\Makefile"
-      Outputs="$(AndroidMxeFullPath)\bin\i686-w64-mingw32.static-gcc">
+      Outputs="$(AndroidMxeFullPath)\bin\i686-w64-mingw32.static-gcc;$(AndroidMxeFullPath)\bin\i686-w64-mingw32.static-cmake">
     <Exec
-        Command="make $(MAKEFLAGS) MXE_TARGETS=&quot;i686-w64-mingw32.static&quot; gcc PREFIX=&quot;$(AndroidMxeFullPath)&quot;"
+        Command="make $(MAKEFLAGS) MXE_TARGETS=&quot;i686-w64-mingw32.static&quot; gcc cmake zlib PREFIX=&quot;$(AndroidMxeFullPath)&quot;"
         WorkingDirectory="..\..\external\mxe"
     />
   </Target>
@@ -132,9 +132,9 @@
       DependsOnTargets="_SetMxeToolchainMakefileTimeToLastCommitTimestamp"
       Condition="$(AndroidSupportedHostJitAbisForConditionalChecks.Contains (':mxe-Win64:'))"
       Inputs="..\..\external\mxe\Makefile"
-      Outputs="$(AndroidMxeFullPath)\bin\x86_64-w64-mingw32.static-gcc">
+      Outputs="$(AndroidMxeFullPath)\bin\x86_64-w64-mingw32.static-gcc;$(AndroidMxeFullPath)\bin\x86_64-w64-mingw32.static-cmake">
     <Exec
-        Command="make $(MAKEFLAGS) MXE_TARGETS=&quot;x86_64-w64-mingw32.static&quot; gcc PREFIX=&quot;$(AndroidMxeFullPath)&quot;"
+        Command="make $(MAKEFLAGS) MXE_TARGETS=&quot;x86_64-w64-mingw32.static&quot; gcc cmake zlib PREFIX=&quot;$(AndroidMxeFullPath)&quot;"
         WorkingDirectory="..\..\external\mxe"
     />
   </Target>
diff --git a/build-tools/libzip/libzip.mdproj b/build-tools/libzip/libzip.mdproj
new file mode 100644
index 00000000000..16b60481b04
--- /dev/null
+++ b/build-tools/libzip/libzip.mdproj
@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ItemType>GenericProject</ItemType>
+    <ProjectGuid>{900A0F71-BAAD-417A-8D1A-8D330297CDD0}</ProjectGuid>
+  </PropertyGroup>
+  <Import Project="..\..\Configuration.props" />
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <OutputPath>..\..\bin\$(Configuration)</OutputPath>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <OutputPath>..\..\bin\$(Configuration)</OutputPath>
+  </PropertyGroup>
+  <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
+  <PropertyGroup>
+    <BuildDependsOn>
+      ResolveReferences;
+      _Configure;
+      _Make
+    </BuildDependsOn>
+  </PropertyGroup>
+  <Import Project="libzip.targets" />
+  <ItemGroup>
+    <ProjectReference Include="..\android-toolchain\android-toolchain.mdproj">
+      <Project>{8FF78EB6-6FC8-46A7-8A15-EBBA9045C5FA}</Project>
+      <Name>android-toolchain</Name>
+      <ReferenceOutputAssembly>False</ReferenceOutputAssembly>
+    </ProjectReference>
+  </ItemGroup>
+</Project>
diff --git a/build-tools/libzip/libzip.projitems b/build-tools/libzip/libzip.projitems
new file mode 100644
index 00000000000..95fd729dbd0
--- /dev/null
+++ b/build-tools/libzip/libzip.projitems
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup>
+    <_LibZipTarget Include="host-mxe-Win64" Condition="$(AndroidSupportedHostJitAbisForConditionalChecks.Contains (':mxe-Win64:'))">
+      <CMake>$(AndroidMxeFullPath)\bin\x86_64-w64-mingw32.static-cmake</CMake>
+      <CMakeFlags></CMakeFlags>
+      <OutputLibrary>libzip.dll</OutputLibrary>
+      <OutputLibraryPath>lib/libzip.dll</OutputLibraryPath>
+    </_LibZipTarget>
+    <_LibZipTarget Include="host-Darwin" Condition="$(AndroidSupportedHostJitAbisForConditionalChecks.Contains (':Darwin:'))">
+      <CMake>cmake</CMake>
+      <CMakeFlags>-DCMAKE_OSX_ARCHITECTURES=&quot;i386;x86_64&quot;</CMakeFlags>
+      <OutputLibrary>libzip.3.0.dylib</OutputLibrary>
+      <OutputLibraryPath>lib/libzip.3.0.dylib</OutputLibraryPath>
+    </_LibZipTarget>
+    <_LibZipTarget Include="host-Linux" Condition="$(AndroidSupportedHostJitAbisForConditionalChecks.Contains (':Linux:'))">
+      <CMake>cmake</CMake>
+      <CMakeFlags></CMakeFlags>
+      <OutputLibrary>libzip.so</OutputLibrary>
+      <OutputLibraryPath>libzip.so</OutputLibraryPath>
+    </_LibZipTarget>
+  </ItemGroup>
+</Project>
diff --git a/build-tools/libzip/libzip.props b/build-tools/libzip/libzip.props
new file mode 100644
index 00000000000..69c45c9a48d
--- /dev/null
+++ b/build-tools/libzip/libzip.props
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+  </PropertyGroup>
+</Project>
diff --git a/build-tools/libzip/libzip.targets b/build-tools/libzip/libzip.targets
new file mode 100644
index 00000000000..b8c27d18330
--- /dev/null
+++ b/build-tools/libzip/libzip.targets
@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <_SourceTopDir>..\..</_SourceTopDir>
+  </PropertyGroup>
+  <UsingTask AssemblyFile="$(_SourceTopDir)\bin\Build$(Configuration)\Xamarin.Android.Tools.BootstrapTasks.dll" TaskName="Xamarin.Android.Tools.BootstrapTasks.GetNugetPackageBasePath" />
+  <Import Project="libzip.props" />
+  <Import Project="libzip.projitems" />
+  <Target Name="_SetCMakeListsTxtTimeToLastCommitTimestamp">
+    <Exec
+        Command="touch -m -t `git log -1 --format=%25cd --date=format-local:%25Y%25m%25d%25H%25M.%25S` CMakeLists.txt"
+        WorkingDirectory="$(LibZipSourceFullPath)"
+    />
+  </Target>
+  <Target Name="_Configure"
+        DependsOnTargets="_SetCMakeListsTxtTimeToLastCommitTimestamp"
+        Inputs="$(LibZipSourceFullPath\CMakeLists.txt"
+        Outputs="$(IntermediateOutputPath)\%(_LibZipTarget.Identity)\Makefile">
+    <MakeDir Directories="@(_LibZipTarget->'$(IntermediateOutputPath)\%(Identity)')" /> 
+    <Exec
+        Command="%(_LibZipTarget.CMake) %(_LibZipTarget.CMakeFlags) $(LibZipSourceFullPath)"
+        WorkingDirectory="@(_LibZipTarget->'$(IntermediateOutputPath)\%(Identity)')"
+    />
+  </Target>
+  <Target Name="_Make"
+        Inputs="$(IntermediateOutputPath)\%(_LibZipTarget.Identity)\Makefile"
+        Outputs="$(IntermediateOutputPath)\%(_LibZipTarget.Identity)\%(_LibZipTarget.OutputLibraryPath)">
+    <Exec
+        Command="make"
+        WorkingDirectory="$(IntermediateOutputPath)\%(_LibZipTarget.Identity)"
+     /> 
+    <Copy SourceFiles="@(_LibZipTarget->'$(IntermediateOutputPath)\%(Identity)\%(_LibZipTarget.OutputLibraryPath)')"
+        DestinationFiles="@(_LibZipTarget->'$(OutputPath)\lib\xbuild\Xamarin\Android\%(_LibZipTarget.OutputLibrary)')"/>
+  </Target>
+</Project>
diff --git a/external/LibZipSharp b/external/LibZipSharp
new file mode 160000
index 00000000000..16c468310c2
--- /dev/null
+++ b/external/LibZipSharp
@@ -0,0 +1 @@
+Subproject commit 16c468310c2fefc8d8e2dfb5aff1e00cf024d5d2
diff --git a/external/libzip b/external/libzip
new file mode 160000
index 00000000000..1d8b1ac4d20
--- /dev/null
+++ b/external/libzip
@@ -0,0 +1 @@
+Subproject commit 1d8b1ac4d20b8ef8d3f5d496dabebaa0ff9019ff
diff --git a/src/Xamarin.Android.Build.Tasks/Tasks/BuildApk.cs b/src/Xamarin.Android.Build.Tasks/Tasks/BuildApk.cs
index 825081852c6..9add94bfbec 100644
--- a/src/Xamarin.Android.Build.Tasks/Tasks/BuildApk.cs
+++ b/src/Xamarin.Android.Build.Tasks/Tasks/BuildApk.cs
@@ -8,8 +8,6 @@
 using System.Text;
 using System.Text.RegularExpressions;
 
-using System.IO.Compression;
-
 using Microsoft.Build.Utilities;
 using Microsoft.Build.Framework;
 
@@ -18,6 +16,7 @@
 using ArchiveFileList = System.Collections.Generic.List<System.Tuple<string, string>>;
 using Mono.Cecil;
 using Xamarin.Android.Build.Utilities;
+using Xamarin.Tools.Zip;
 
 namespace Xamarin.Android.Tasks
 {
@@ -111,12 +110,12 @@ void ExecuteWithAbi (string supportedAbis, string apkInputPath, string apkOutput
 			ArchiveFileList files = new ArchiveFileList ();
 			if (apkInputPath != null)
 				File.Copy (apkInputPath, apkOutputPath + "new", overwrite: true);
-			using (var apk = ZipFile.Open (apkOutputPath + "new", apkInputPath != null ? ZipArchiveMode.Update : ZipArchiveMode.Create)) {
+			using (var apk = ZipArchive.Open (apkOutputPath + "new", apkInputPath != null ? FileMode.Open : FileMode.Create )) {
 				apk.AddEntry ("NOTICE",
 						Assembly.GetExecutingAssembly ().GetManifestResourceStream ("NOTICE.txt"));
 
 				// Add classes.dx
-				apk.AddFiles (DalvikClasses, string.Empty);
+				apk.AddFiles (DalvikClasses);
 
 				if (EmbedAssemblies && !BundleAssemblies)
 					AddAssemblies (apk);
@@ -128,7 +127,7 @@ void ExecuteWithAbi (string supportedAbis, string apkInputPath, string apkOutput
 				AddNativeLibrariesFromAssemblies (apk, supportedAbis);
 
 				foreach (ITaskItem typemap in TypeMappings) {
-					apk.AddFile (typemap.ItemSpec, directoryPathInZip: "", compressionLevel: CompressionLevel.NoCompression);
+					apk.AddFile (typemap.ItemSpec, compressionMethod: CompressionMethod.Store);
 				}
 
 				foreach (var file in files) {
@@ -138,7 +137,7 @@ void ExecuteWithAbi (string supportedAbis, string apkInputPath, string apkOutput
 						Log.LogWarning (null, "XA4301", null, file.Item1, 0, 0, 0, 0, "Apk already contains the item {0}; ignoring.", item);
 						continue;
 					}
-					apk.AddFile (file.Item1, file.Item2);
+					apk.AddFile (file.Item1, item);
 				}
 				if (_Debug)
 					AddGdbservers (apk, files, supportedAbis, debugServer);
@@ -156,23 +155,22 @@ void ExecuteWithAbi (string supportedAbis, string apkInputPath, string apkOutput
 				jarFilePaths = MonoAndroidHelper.DistinctFilesByContent (jarFilePaths);
 
 				foreach (var jarFile in jarFilePaths) {
-					using (var jar = new ZipArchive (File.Open (jarFile, FileMode.Open), ZipArchiveMode.Read)) {
-						foreach (var jarItem in jar.Entries.Where (ze => !ze.IsDirectory () && !ze.FullName.StartsWith ("META-INF") && !ze.FullName.EndsWith (".class") && !ze.FullName.EndsWith (".java") && !ze.FullName.EndsWith ("MANIFEST.MF"))) {
-							byte[] data;
-							using (var d = new System.IO.MemoryStream ())
-							using (var i = jarItem.Open ()) {
-								i.CopyTo (d);
+					using (var jar = ZipArchive.Open (File.Open (jarFile, FileMode.Open))) {
+						foreach (var jarItem in jar.Where (ze => !ze.IsDirectory && !ze.FullName.StartsWith ("META-INF") && !ze.FullName.EndsWith (".class") && !ze.FullName.EndsWith (".java") && !ze.FullName.EndsWith ("MANIFEST.MF"))) {
+							byte [] data;
+							using (var d = new System.IO.MemoryStream ()) {
+								jarItem.Extract (d);
 								data = d.ToArray ();
 							}
-							if (apk.Entries.Any (e => e.FullName == jarItem.FullName))
+							if (apk.Any (e => e.FullName == jarItem.FullName))
 								Log.LogMessage ("Warning: failed to add jar entry {0} from {1}: the same file already exists in the apk", jarItem.FullName, Path.GetFileName (jarFile));
 							else
-								apk.AddEntry (jarItem.FullName, data);
+								apk.AddEntry (data, jarItem.FullName);
 						}
 					}
 				}
 				if (StubApplicationDataFile != null && File.Exists (StubApplicationDataFile))
-					AddZipEntry (apk, StubApplicationDataFile, string.Empty);
+					apk.AddFile (StubApplicationDataFile, Path.GetFileName (StubApplicationDataFile));
 			}
 			MonoAndroidHelper.CopyIfZipChanged (apkOutputPath + "new", apkOutputPath);
 			File.Delete (apkOutputPath + "new");
@@ -244,11 +242,6 @@ public override bool Execute ()
 			return !Log.HasLoggedErrors;
 		}
 
-		void AddZipEntry (ZipArchive apk, string file, string path)
-		{
-			apk.AddFile (file, path);
-		}
-
 		private void AddAssemblies (ZipArchive apk)
 		{
 			bool debug = _Debug;
@@ -256,7 +249,7 @@ private void AddAssemblies (ZipArchive apk)
 
 			foreach (ITaskItem assembly in ResolvedUserAssemblies) {
 				// Add assembly
-				apk.AddFile (assembly.ItemSpec, GetTargetDirectory (assembly.ItemSpec), compressionLevel: CompressionLevel.NoCompression);
+				apk.AddFile (assembly.ItemSpec, GetTargetDirectory (assembly.ItemSpec), compressionMethod: CompressionMethod.Store);
 
 				// Try to add config if exists
 				var config = Path.ChangeExtension (assembly.ItemSpec, "dll.config");
@@ -267,7 +260,7 @@ private void AddAssemblies (ZipArchive apk)
 					var symbols = Path.ChangeExtension (assembly.ItemSpec, "dll.mdb");
 
 					if (File.Exists (symbols))
-						apk.AddFile (symbols, "assemblies", compressionLevel: CompressionLevel.NoCompression);
+						apk.AddFile (symbols, "assemblies", compressionMethod: CompressionMethod.Store);
 				}
 			}
 
@@ -276,7 +269,7 @@ private void AddAssemblies (ZipArchive apk)
 
 			// Add framework assemblies
 			foreach (ITaskItem assembly in ResolvedFrameworkAssemblies) {
-				apk.AddFile (assembly.ItemSpec, "assemblies", compressionLevel: CompressionLevel.NoCompression);
+				apk.AddFile (assembly.ItemSpec, "assemblies", compressionMethod: CompressionMethod.Store);
 				var config = Path.ChangeExtension (assembly.ItemSpec, "dll.config");
 				AddAssemblyConfigEntry (apk, config);
 				// Try to add symbols if Debug
@@ -284,7 +277,7 @@ private void AddAssemblies (ZipArchive apk)
 					var symbols = Path.ChangeExtension (assembly.ItemSpec, "dll.mdb");
 
 					if (File.Exists (symbols))
-						apk.AddFile (symbols, "assemblies", compressionLevel: CompressionLevel.NoCompression);
+						apk.AddFile (symbols, "assemblies", compressionMethod: CompressionMethod.Store);
 				}
 			}
 		}
@@ -299,7 +292,7 @@ void AddAssemblyConfigEntry (ZipArchive apk, string configFile)
 				source.CopyTo (dest);
 				dest.WriteByte (0);
 				dest.Position = 0;
-				apk.AddEntry ("assemblies/" + Path.GetFileName (configFile), dest, compressionLevel: CompressionLevel.NoCompression);
+				apk.AddEntry ("assemblies/" + Path.GetFileName (configFile), dest, compressionMethod: CompressionMethod.Store);
 			}
 		}
 
@@ -462,18 +455,19 @@ void AddNativeLibrariesFromAssemblies (ZipArchive apk, string supportedAbis)
 						continue;
 					var data = ressozip.GetResourceData ();
 					using (var ms = new MemoryStream (data)) {
-						using (var zip = new ZipArchive (ms, ZipArchiveMode.Read)) {
-							foreach (var e in zip.Entries.Where (x => abis.Any (a => x.FullName.Contains (a)))) {
-								if (e.IsDirectory ())
+						using (var zip = ZipArchive.Open (ms)) {
+							foreach (var e in zip.Where (x => abis.Any (a => x.FullName.Contains (a)))) {
+								if (e.IsDirectory)
 									continue;
 								var key = e.FullName.Replace ("native_library_imports", "lib");
-								if (apk.ContainsEntry (key)) {
+								if (apk.Any(k => k.FullName  == key)) {
 									Log.LogCodedWarning ("4301", "Apk already contains the item {0}; ignoring.", key);
 									continue;
 								}
 								using (var s = new MemoryStream ()) {
 									e.Extract (s);
-									apk.AddEntry (key, s.ToArray ());
+									s.Position = 0;
+									apk.AddEntry (s.ToArray (),key);
 								}
 							}
 						}
diff --git a/src/Xamarin.Android.Build.Tasks/Tasks/CreateLibraryResourceArchive.cs b/src/Xamarin.Android.Build.Tasks/Tasks/CreateLibraryResourceArchive.cs
index b71e0c17466..820217df8d6 100644
--- a/src/Xamarin.Android.Build.Tasks/Tasks/CreateLibraryResourceArchive.cs
+++ b/src/Xamarin.Android.Build.Tasks/Tasks/CreateLibraryResourceArchive.cs
@@ -8,7 +8,7 @@
 using Microsoft.Build.Utilities;
 using Microsoft.Build.Framework;
 using System.Text.RegularExpressions;
-using System.IO.Compression;
+using Xamarin.Tools.Zip;
 
 using Xamarin.Android.Tools;
 
@@ -79,7 +79,8 @@ public override bool Execute ()
 					string tmpname = Path.Combine (Path.GetTempPath (), "monodroid_import_" + Guid.NewGuid ().ToString ());
 					try {
 						Directory.CreateDirectory (tmpname);
-						ZipFile.ExtractToDirectory (p, tmpname, new System.Text.UTF8Encoding (false));
+						var archive = ZipArchive.Open (p, FileMode.Open);
+						archive.ExtractAll (tmpname);
 
 						if (!CopyLibraryContent (tmpname, p.EndsWith (".aar", StringComparison.OrdinalIgnoreCase)))
 							return false;
@@ -91,7 +92,7 @@ public override bool Execute ()
 
 			// Archive them in a zip.
 			using (var stream = new MemoryStream ()) {
-				using (var zip = new ZipArchive (stream, ZipArchiveMode.Create, true, new System.Text.UTF8Encoding (false))) {
+				using (var zip = ZipArchive.Create (stream)) {
 					zip.AddDirectory (OutputDirectory, outDirInfo.Name);
 				}
 				stream.Position = 0;
diff --git a/src/Xamarin.Android.Build.Tasks/Tasks/CreateManagedLibraryResourceArchive.cs b/src/Xamarin.Android.Build.Tasks/Tasks/CreateManagedLibraryResourceArchive.cs
index 9a648fb00f9..7f306bc4068 100644
--- a/src/Xamarin.Android.Build.Tasks/Tasks/CreateManagedLibraryResourceArchive.cs
+++ b/src/Xamarin.Android.Build.Tasks/Tasks/CreateManagedLibraryResourceArchive.cs
@@ -8,7 +8,7 @@
 using Microsoft.Build.Utilities;
 using Microsoft.Build.Framework;
 using System.Text.RegularExpressions;
-using System.IO.Compression;
+using Xamarin.Tools.Zip;
 
 using Xamarin.Android.Tools;
 
@@ -106,7 +106,8 @@ public override bool Execute ()
 
 			// Archive them in a zip.
 			using (var stream = new MemoryStream ()) {
-				using (var zip = new ZipArchive (stream, ZipArchiveMode.Create, true, new System.Text.UTF8Encoding (false))) {
+				using (var zip = ZipArchive.Create (stream)) {
+					Log.LogDebugMessage ($" {OutputDirectory} {outDirInfo.Name} ");
 					zip.AddDirectory (OutputDirectory, outDirInfo.Name);
 				}
 				stream.Position = 0;
diff --git a/src/Xamarin.Android.Build.Tasks/Tasks/CreateNativeLibraryArchive.cs b/src/Xamarin.Android.Build.Tasks/Tasks/CreateNativeLibraryArchive.cs
index 9e81ec34c50..d3e68ed7f51 100644
--- a/src/Xamarin.Android.Build.Tasks/Tasks/CreateNativeLibraryArchive.cs
+++ b/src/Xamarin.Android.Build.Tasks/Tasks/CreateNativeLibraryArchive.cs
@@ -8,7 +8,7 @@
 using Microsoft.Build.Utilities;
 using Microsoft.Build.Framework;
 using System.Text.RegularExpressions;
-using System.IO.Compression;
+using Xamarin.Tools.Zip;
 
 using Xamarin.Android.Tools;
 
@@ -64,7 +64,7 @@ public override bool Execute ()
 
 			// Archive native libraries in a zip.
 			using (var stream = new MemoryStream ()) {
-				using (var zip = new ZipArchive (stream, ZipArchiveMode.Create, true, new System.Text.UTF8Encoding (false))) {
+				using (var zip = ZipArchive.Create (stream)) {
 					zip.AddDirectory (OutputDirectory, outDirInfo.Name);
 				}
 				stream.Position = 0;
diff --git a/src/Xamarin.Android.Build.Tasks/Tasks/GetAdditionalResourcesFromAssemblies.cs b/src/Xamarin.Android.Build.Tasks/Tasks/GetAdditionalResourcesFromAssemblies.cs
index 78c403c026f..1c4d1620b41 100644
--- a/src/Xamarin.Android.Build.Tasks/Tasks/GetAdditionalResourcesFromAssemblies.cs
+++ b/src/Xamarin.Android.Build.Tasks/Tasks/GetAdditionalResourcesFromAssemblies.cs
@@ -162,7 +162,7 @@ bool ExtractArchive (string url, string file, string contentDir)
 					LogMessage ("Extracting {0} to {1}", file, contentDir);
 					using (var zip = MonoAndroidHelper.ReadZipFile (file)) {
 						int extracted = 0;
-						var o = Math.Max(1, (zip.Entries.Count / 10));
+						var o = Math.Max(1, (zip.EntryCount / 10));
 						Files.ExtractAll (zip, contentDir, (progress, total) => {
 							if ((progress % o) != 0 || extracted == progress || progress == 0)
 								return;
diff --git a/src/Xamarin.Android.Build.Tasks/Tasks/Proguard.cs b/src/Xamarin.Android.Build.Tasks/Tasks/Proguard.cs
index 6b1c8aa47a8..c9a94cc1b9c 100644
--- a/src/Xamarin.Android.Build.Tasks/Tasks/Proguard.cs
+++ b/src/Xamarin.Android.Build.Tasks/Tasks/Proguard.cs
@@ -13,6 +13,7 @@
 using System.Text.RegularExpressions;
 using Xamarin.Android.Build.Utilities;
 using System.IO.Compression;
+using Xamarin.Tools.Zip;
 
 namespace Xamarin.Android.Tasks
 {
@@ -123,7 +124,7 @@ protected override string GenerateCommandLineCommands ()
 
 			if (File.Exists (ProguardJarInput))
 				File.Delete (ProguardJarInput);
-			using (var zip = ZipFile.Open (ProguardJarInput, ZipArchiveMode.Create, new System.Text.UTF8Encoding (false))) {
+			using (var zip = ZipArchive.Open (ProguardJarInput, FileMode.Create)) {
 				foreach (var file in Directory.GetFiles (classesFullPath, "*", SearchOption.AllDirectories))
 					zip.AddFile (file, Path.GetDirectoryName (file.Substring (classesFullPath.Length)));
 			}
diff --git a/src/Xamarin.Android.Build.Tasks/Utilities/Files.cs b/src/Xamarin.Android.Build.Tasks/Utilities/Files.cs
index 2410688a5f4..c9b38431e21 100644
--- a/src/Xamarin.Android.Build.Tasks/Utilities/Files.cs
+++ b/src/Xamarin.Android.Build.Tasks/Utilities/Files.cs
@@ -2,7 +2,7 @@
 using System.IO;
 using System.Security.Cryptography;
 
-using System.IO.Compression;
+using Xamarin.Tools.Zip;
 #if MSBUILD
 using Microsoft.Build.Utilities;
 using Xamarin.Android.Tasks;
@@ -157,9 +157,9 @@ static string HashZip (Stream stream)
 			string hashes = String.Empty;
 
 			try {
-				using (var zip = new ZipArchive (stream, ZipArchiveMode.Read)) {
-					foreach (var item in zip.Entries) {
-						hashes += String.Format ("{0}{1}", item.FullName, item.Hash());
+				using (var zip = ZipArchive.Open (stream)) {
+					foreach (var item in zip) {
+						hashes += String.Format ("{0}{1}", item.FullName, item.CRC);
 					}
 				}
 			} catch {
@@ -178,8 +178,8 @@ static string HashZip (string filename)
 					return File.ReadAllText (filename + ".hash");
 
 				using (var zip = ReadZipFile (filename)) {
-					foreach (var item in zip.Entries) {
-						hashes += String.Format ("{0}{1}", item.FullName, item.Hash());
+					foreach (var item in zip) {
+						hashes += String.Format ("{0}{1}", item.FullName, item.CRC);
 					}
 				}
 			} catch {
@@ -190,26 +190,26 @@ static string HashZip (string filename)
 
 		public static ZipArchive ReadZipFile (string filename)
 		{
-			return ZipFile.Open (filename, ZipArchiveMode.Read, new System.Text.UTF8Encoding (false));
+			return ZipArchive.Open (filename, FileMode.Open);
 		}
 
 		public static void ExtractAll(ZipArchive zip, string destination, Action<int, int> progressCallback = null)
 		{
 			int i = 0;
-			int total = zip.Entries.Count;
-			foreach (var entry in zip.Entries) {
+			int total = (int)zip.EntryCount;
+			foreach (var entry in zip) {
 				if (entry.FullName.Contains ("/__MACOSX/") ||
 						entry.FullName.EndsWith ("/__MACOSX", StringComparison.OrdinalIgnoreCase) ||
 						entry.FullName.EndsWith ("/.DS_Store", StringComparison.OrdinalIgnoreCase))
 					continue;
-				if (entry.IsDirectory ()) {
+				if (entry.IsDirectory) {
 					Directory.CreateDirectory (Path.Combine (destination, entry.FullName));
 					continue;
 				}
 				if (progressCallback != null)
 					progressCallback (i++, total);
 				Directory.CreateDirectory (Path.Combine (destination, Path.GetDirectoryName (entry.FullName)));
-				entry.ExtractToFile (Path.Combine (destination, entry.FullName), overwrite: true);
+				entry.Extract (destination, entry.FullName);
 			}
 		}
 
diff --git a/src/Xamarin.Android.Build.Tasks/Utilities/MonoAndroidHelper.cs b/src/Xamarin.Android.Build.Tasks/Utilities/MonoAndroidHelper.cs
index 71667f439b1..1e83db257da 100644
--- a/src/Xamarin.Android.Build.Tasks/Utilities/MonoAndroidHelper.cs
+++ b/src/Xamarin.Android.Build.Tasks/Utilities/MonoAndroidHelper.cs
@@ -7,8 +7,7 @@
 using System.Security.Cryptography;
 using Mono.Security.Cryptography;
 using Xamarin.Android.Build.Utilities;
-using System.IO.Compression;
-
+using Xamarin.Tools.Zip;
 
 #if MSBUILD
 using Microsoft.Build.Framework;
diff --git a/src/Xamarin.Android.Build.Tasks/Utilities/ZipArchiveExtensions.cs b/src/Xamarin.Android.Build.Tasks/Utilities/ZipArchiveExtensions.cs
deleted file mode 100644
index 6ce8edf160b..00000000000
--- a/src/Xamarin.Android.Build.Tasks/Utilities/ZipArchiveExtensions.cs
+++ /dev/null
@@ -1,116 +0,0 @@
-using System;
-using System.IO;
-using System.IO.Compression;
-using System.Collections.Generic;
-using System.Text;
-using System.Linq;
-using System.Security.Cryptography;
-
-namespace Xamarin.Android.Tasks
-{
-	static class ZipArchiveExtensions 
-	{
-		public static void AddEntry (this ZipArchive archive, string entryName, Stream data,
-			CompressionLevel compressionLevel = CompressionLevel.Optimal )
-		{
-			ZipArchiveEntry entry = archive.CreateEntry(entryName, compressionLevel: compressionLevel);
-			using (StreamWriter writer = new StreamWriter(entry.Open()))
-			{
-				data.CopyTo (writer.BaseStream);
-				writer.Flush ();
-			}
-		}
-
-		public static void AddEntry (this ZipArchive archive, string entryName, byte[] data,
-			CompressionLevel compressionLevel = CompressionLevel.Optimal)
-		{
-			ZipArchiveEntry entry = archive.CreateEntry (entryName, compressionLevel: compressionLevel);
-			using (StreamWriter writer = new StreamWriter (entry.Open ())) {
-				writer.BaseStream.Write (data, 0, data.Length);
-				writer.Flush ();
-			}
-		}
-
-		public static void AddEntry (this ZipArchive archive, string entryName, string s, Encoding encoding,
-			CompressionLevel compressionLevel = CompressionLevel.Optimal)
-		{
-			ZipArchiveEntry entry = archive.CreateEntry (entryName, compressionLevel: compressionLevel);
-			using (StreamWriter writer = new StreamWriter (entry.Open ())) {
-				var data = encoding.GetBytes (s);
-				writer.BaseStream.Write (data, 0, data.Length);
-				writer.Flush ();
-			}
-		}
-
-		internal static string ArchiveNameForFile (string filename, string directoryPathInZip)
-		{
-			string pathName;
-			if (string.IsNullOrEmpty (directoryPathInZip)) {
-				pathName = Path.GetFileName (filename);
-			}
-			else {
-				pathName = Path.Combine (directoryPathInZip, Path.GetFileName (filename));
-			}
-			return pathName.Replace ("\\", "/");
-		}
-
-		public static ZipArchiveEntry AddFile (this ZipArchive archive, string fileName, string directoryPathInZip = null, CompressionLevel compressionLevel = CompressionLevel.Optimal )
-		{
-			ZipArchiveEntry entry = archive.CreateEntry(ArchiveNameForFile(fileName, directoryPathInZip), compressionLevel: compressionLevel);
-			using (StreamWriter writer = new StreamWriter(entry.Open()))
-			{
-				var data = File.ReadAllBytes (fileName);
-				writer.BaseStream.Write (data, 0, data.Length);
-			}
-			return entry;
-		}
-
-		public static void AddFiles (this ZipArchive archive, IEnumerable<string> fileNames, string directoryPathInZip)
-		{
-			foreach (var file in fileNames) {
-				AddFile (archive, file, directoryPathInZip);
-			}
-		}
-
-		public static bool ContainsEntry (this ZipArchive archive, string entryName)
-		{
-			return archive.Entries.Any (x => string.Compare (x.FullName, entryName, StringComparison.OrdinalIgnoreCase) == 0);
-		}
-
-		public static bool IsDirectory (this ZipArchiveEntry entry)
-		{
-			return entry.FullName.EndsWith ("/", StringComparison.OrdinalIgnoreCase);
-		}
-
-		public static void Extract (this ZipArchiveEntry entry, Stream stream)
-		{
-			entry.Open ().CopyTo (stream);
-		}
-
-		public static void Extract (this ZipArchiveEntry entry, string destination)
-		{
-			entry.ExtractToFile (destination, overwrite: true);
-		}
-
-		public static void AddDirectory (this ZipArchive archive, string folder, string folderInArchive)
-		{
-			string root = folderInArchive;
-			foreach(var fileName in Directory.GetFiles (folder)) {
-				archive.AddFile (fileName, root);
-			}
-			foreach (var dir in Directory.GetDirectories (folder)) {
-				var internalDir = dir.Replace ("./", string.Empty).Replace (folder, string.Empty);
-				archive.AddDirectory (dir, folderInArchive + internalDir);
-			}
-		}
-
-		public static string Hash (this ZipArchiveEntry entry)
-		{
-			using (var stream = entry.Open ())
-			using (var sha1 = SHA1.Create ()) {
-				return Convert.ToBase64String (sha1.ComputeHash (stream));
-			}
-		}
-	}
-}
-
diff --git a/src/Xamarin.Android.Build.Tasks/Xamarin.Android.Build.Tasks.csproj b/src/Xamarin.Android.Build.Tasks/Xamarin.Android.Build.Tasks.csproj
index 543c3a3bd88..d77bff6b3da 100644
--- a/src/Xamarin.Android.Build.Tasks/Xamarin.Android.Build.Tasks.csproj
+++ b/src/Xamarin.Android.Build.Tasks/Xamarin.Android.Build.Tasks.csproj
@@ -34,15 +34,13 @@
   </PropertyGroup>
   <PropertyGroup>
     <DefineConstants Condition="'$(__XA_NO_PREVIEW_L_SUPPORT__)' != ''">$(DefineConstants);XA_NO_PREVIEW_L_SUPPORT</DefineConstants>
-    <AndroidGeneratedClassDirectory Condition=" '$(AndroidGeneratedClassDirectory)' == '' "  >..\..\src\Mono.Android\obj\$(Configuration)\android-$(AndroidApiLevel)</AndroidGeneratedClassDirectory>
+    <AndroidGeneratedClassDirectory Condition=" '$(AndroidGeneratedClassDirectory)' == '' ">..\..\src\Mono.Android\obj\$(Configuration)\android-$(AndroidApiLevel)</AndroidGeneratedClassDirectory>
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="Microsoft.Build.Framework" />
     <Reference Include="Microsoft.Build.Utilities.v4.0" />
     <Reference Include="System" />
     <Reference Include="System.Core" />
-    <Reference Include="System.IO.Compression" />
-    <Reference Include="System.IO.Compression.FileSystem" />
     <Reference Include="System.Xml.Linq" />
     <Reference Include="System.Xml" />
     <Reference Include="Mono.Cecil">
@@ -63,8 +61,6 @@
     <Reference Include="FSharp.Compiler.CodeDom">
       <HintPath>..\..\packages\FSharp.Compiler.CodeDom.1.0.0.1\lib\net40\FSharp.Compiler.CodeDom.dll</HintPath>
     </Reference>
-    <Reference Include="System.IO.Compression.FileSystem" />
-    <Reference Include="System.IO.Compression" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="$(IntermediateOutputPath)Profile.g.cs" />
@@ -117,7 +113,6 @@
     <Compile Include="Utilities\JavaResourceParser.cs" />
     <Compile Include="Utilities\ManifestDocumentElement.cs" />
     <Compile Include="Utilities\ManifestDocument.cs" />
-    <Compile Include="Utilities\ZipArchiveExtensions.cs" />    
     <Compile Include="Mono.Android\MetaDataAttribute.Partial.cs" />
     <Compile Include="Utilities\MonoAndroidHelper.cs" />
     <None Include="Linker\MonoDroid.Tuner\PreserveCode.cs" />
@@ -640,6 +635,10 @@
       <Name>class-parse</Name>
       <ReferenceOutputAssembly>False</ReferenceOutputAssembly>
     </ProjectReference>
+    <ProjectReference Include="$(LibZipSharpSourceFullPath)\libZipSharp.csproj">
+      <Project>{E248B2CA-303B-4645-ADDC-9D4459D550FD}</Project>
+      <Name>libZipSharp</Name>
+    </ProjectReference>
   </ItemGroup>
   <ItemGroup>
     <Folder Include="pdb2mdb\" />
diff --git a/src/Xamarin.Android.Build.Utilities/Xamarin.Android.Build.Utilities.csproj b/src/Xamarin.Android.Build.Utilities/Xamarin.Android.Build.Utilities.csproj
index 65858ccfed0..da208f36abe 100644
--- a/src/Xamarin.Android.Build.Utilities/Xamarin.Android.Build.Utilities.csproj
+++ b/src/Xamarin.Android.Build.Utilities/Xamarin.Android.Build.Utilities.csproj
@@ -31,8 +31,6 @@
     <Reference Include="System" />
     <Reference Include="System.Xml" />
     <Reference Include="System.Xml.Linq" />
-    <Reference Include="System.IO.Compression" />
-    <Reference Include="System.IO.Compression.FileSystem" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Properties\AssemblyInfo.cs" />
@@ -58,4 +56,4 @@
   <ItemGroup>
     <Folder Include="Sdks\" />
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>