diff --git a/build.py b/build.py
index ae9270a68..858dbb826 100755
--- a/build.py
+++ b/build.py
@@ -361,7 +361,7 @@ def zip_uninstaller(args):
 	header('Output: ' + output)
 
 def sign_adjust_zip(unsigned, output):
-	signer_name = 'zipsigner-2.1.jar'
+	signer_name = 'zipsigner-2.2.jar'
 	jarsigner = os.path.join('utils', 'build', 'libs', signer_name)
 
 	if not os.path.exists(jarsigner):
diff --git a/utils/build.gradle b/utils/build.gradle
index bc18545a3..a59b5ef49 100644
--- a/utils/build.gradle
+++ b/utils/build.gradle
@@ -15,7 +15,7 @@ jar {
 shadowJar {
     baseName = 'zipsigner'
     classifier = null
-    version = 2.1
+    version = 2.2
 }
 
 buildscript {
@@ -23,7 +23,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.github.jengelman.gradle.plugins:shadow:2.0.2'
+        classpath 'com.github.jengelman.gradle.plugins:shadow:2.0.4'
     }
 }
 
@@ -33,6 +33,6 @@ repositories {
 
 dependencies {
     implementation fileTree(include: ['*.jar'], dir: 'libs')
-    implementation 'org.bouncycastle:bcprov-jdk15on:1.58'
-    implementation 'org.bouncycastle:bcpkix-jdk15on:1.58'
+    implementation 'org.bouncycastle:bcprov-jdk15on:1.59'
+    implementation 'org.bouncycastle:bcpkix-jdk15on:1.59'
 }
diff --git a/utils/src/main/java/com/topjohnwu/utils/ReusableInputStream.java b/utils/src/main/java/com/topjohnwu/utils/ReusableInputStream.java
new file mode 100644
index 000000000..d4627d24f
--- /dev/null
+++ b/utils/src/main/java/com/topjohnwu/utils/ReusableInputStream.java
@@ -0,0 +1,28 @@
+package com.topjohnwu.utils;
+
+import java.io.BufferedInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+public class ReusableInputStream extends BufferedInputStream {
+
+    public ReusableInputStream(InputStream in) {
+        super(in);
+        mark(Integer.MAX_VALUE);
+    }
+
+    public ReusableInputStream(InputStream in, int size) {
+        super(in, size);
+        mark(Integer.MAX_VALUE);
+    }
+
+    @Override
+    public void close() throws IOException {
+        /* Reset at close so we can reuse it */
+        reset();
+    }
+
+    public void destroy() throws IOException {
+        super.close();
+    }
+}
diff --git a/utils/src/main/java/com/topjohnwu/utils/SignAPK.java b/utils/src/main/java/com/topjohnwu/utils/SignAPK.java
index 084421bb2..709efbcbf 100644
--- a/utils/src/main/java/com/topjohnwu/utils/SignAPK.java
+++ b/utils/src/main/java/com/topjohnwu/utils/SignAPK.java
@@ -18,6 +18,7 @@ import org.bouncycastle.operator.jcajce.JcaContentSignerBuilder;
 import org.bouncycastle.operator.jcajce.JcaDigestCalculatorProviderBuilder;
 import org.bouncycastle.util.encoders.Base64;
 
+import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
@@ -73,19 +74,31 @@ public class SignAPK {
                                JarMap input, OutputStream output) throws Exception {
         File temp1 = File.createTempFile("signAPK", null);
         File temp2 = File.createTempFile("signAPK", null);
+        if (cert == null) {
+            cert = SignAPK.class.getResourceAsStream("/keys/testkey.x509.pem");
+        }
+        if (key == null) {
+            key = SignAPK.class.getResourceAsStream("/keys/testkey.pk8");
+        }
+
+        ReusableInputStream c = new ReusableInputStream(cert);
+        ReusableInputStream k = new ReusableInputStream(key);
+
         try {
             try (OutputStream out = new BufferedOutputStream(new FileOutputStream(temp1))) {
-                signZip(cert, key, input, out, false);
+                signZip(c, k, input, out, false);
             }
 
             ZipAdjust.adjust(temp1, temp2);
 
             try (JarMap map = new JarMap(temp2, false)) {
-                signZip(cert, key, map, output, true);
+                signZip(c, k, map, output, true);
             }
         } finally {
             temp1.delete();
             temp2.delete();
+            c.destroy();
+            k.destroy();
         }
     }
 
diff --git a/utils/src/main/java/com/topjohnwu/utils/ZipSigner.java b/utils/src/main/java/com/topjohnwu/utils/ZipSigner.java
index b51afd9cc..869745d37 100644
--- a/utils/src/main/java/com/topjohnwu/utils/ZipSigner.java
+++ b/utils/src/main/java/com/topjohnwu/utils/ZipSigner.java
@@ -28,8 +28,8 @@ public class ZipSigner {
         InputStream key = null;
 
         if (args.length - argStart == 4) {
-            cert = new BufferedInputStream(new FileInputStream(new File(args[argStart])));
-            key = new BufferedInputStream(new FileInputStream(new File(args[argStart + 1])));
+            cert = new FileInputStream(new File(args[argStart]));
+            key = new FileInputStream(new File(args[argStart + 1]));
             argStart += 2;
         }