--- a/src/jdk.crypto.mscapi/windows/classes/sun/security/mscapi/PRNG.java	Mon Dec 03 14:16:39 2018 +0100
+++ b/src/jdk.crypto.mscapi/windows/classes/sun/security/mscapi/PRNG.java	Mon Dec 03 23:58:15 2018 +0800
@@ -25,6 +25,7 @@
 
 package sun.security.mscapi;
 
+import java.lang.ref.Cleaner;
 import java.security.ProviderException;
 import java.security.SecureRandomSpi;
 
@@ -43,12 +44,31 @@
      * The CryptGenRandom function fills a buffer with cryptographically random
      * bytes.
      */
-    private static native byte[] generateSeed(int length, byte[] seed);
+    private static native byte[] generateSeed(long ctxt, int length, byte[] seed);
+    private static native long getContext();
+    private static native void releaseContext(long ctxt);
+    private static final Cleaner CLEANER = Cleaner.create();
+
+    private transient long ctxt;
+
+    private static class State implements Runnable {
+        private final long ctxt;
 
+        State(long ctxt) {
+            this.ctxt = ctxt;
+        }
+
+        @Override
+        public void run() {
+            releaseContext(ctxt);
+        }
+    }
     /**
      * Creates a random number generator.
      */
     public PRNG() {
+        ctxt = getContext();
+        CLEANER.register(this, new State(ctxt));
     }
 
     /**
@@ -59,9 +79,9 @@
      * @param seed the seed.
      */
     @Override
-    protected void engineSetSeed(byte[] seed) {
+    protected synchronized void engineSetSeed(byte[] seed) {
         if (seed != null) {
-            generateSeed(-1, seed);
+            generateSeed(ctxt, -1, seed);
         }
     }
 
@@ -71,9 +91,9 @@
      * @param bytes the array to be filled in with random bytes.
      */
     @Override
-    protected void engineNextBytes(byte[] bytes) {
+    protected synchronized void engineNextBytes(byte[] bytes) {
         if (bytes != null) {
-            if (generateSeed(0, bytes) == null) {
+            if (generateSeed(ctxt, 0, bytes) == null) {
                 throw new ProviderException("Error generating random bytes");
             }
         }
@@ -88,12 +108,20 @@
      * @return the seed bytes.
      */
     @Override
-    protected byte[] engineGenerateSeed(int numBytes) {
-        byte[] seed = generateSeed(numBytes, null);
+    protected synchronized byte[] engineGenerateSeed(int numBytes) {
+        byte[] seed = generateSeed(ctxt, numBytes, null);
 
         if (seed == null) {
             throw new ProviderException("Error generating seed bytes");
         }
         return seed;
     }
+
+    private void readObject(java.io.ObjectInputStream s)
+            throws java.io.IOException, ClassNotFoundException
+    {
+        s.defaultReadObject();
+        ctxt = getContext();
+        CLEANER.register(this, new State(ctxt));
+    }
 }

--- a/src/jdk.crypto.mscapi/windows/native/libsunmscapi/security.cpp	Mon Dec 03 14:16:39 2018 +0100
+++ b/src/jdk.crypto.mscapi/windows/native/libsunmscapi/security.cpp	Mon Dec 03 23:58:15 2018 +0800
@@ -242,32 +242,54 @@
 
 /*
  * Class:     sun_security_mscapi_PRNG
+ * Method:    getContext
+ * Signature: ()J
+ */
+JNIEXPORT jlong JNICALL Java_sun_security_mscapi_PRNG_getContext
+        (JNIEnv *env, jclass clazz) {
+    HCRYPTPROV hCryptProv = NULL;
+    if(::CryptAcquireContext(
+       &hCryptProv,
+       NULL,
+       NULL,
+       PROV_RSA_FULL,
+       CRYPT_VERIFYCONTEXT) == FALSE)
+    {
+        ThrowException(env, PROVIDER_EXCEPTION, GetLastError());
+    }
+    return hCryptProv;
+}
+
+
+/*
+ * Class:     sun_security_mscapi_PRNG
+ * Method:    releaseContext
+ * Signature: (J)V
+ */
+JNIEXPORT void JNICALL Java_sun_security_mscapi_PRNG_releaseContext
+        (JNIEnv *env, jclass clazz, jlong ctxt) {
+    if (ctxt) {
+        ::CryptReleaseContext((HCRYPTPROV)ctxt, 0);
+    }
+}
+
+
+/*
+ * Class:     sun_security_mscapi_PRNG
  * Method:    generateSeed
- * Signature: (I[B)[B
+ * Signature: (JI[B)[B
  */
 JNIEXPORT jbyteArray JNICALL Java_sun_security_mscapi_PRNG_generateSeed
-  (JNIEnv *env, jclass clazz, jint length, jbyteArray seed)
+  (JNIEnv *env, jclass clazz, jlong ctxt, jint length, jbyteArray seed)
 {
 
-    HCRYPTPROV hCryptProv = NULL;
+    HCRYPTPROV hCryptProv = (HCRYPTPROV)ctxt;
     jbyte*     reseedBytes = NULL;
     jbyte*     seedBytes = NULL;
     jbyteArray result = NULL;
 
     __try
     {
-        //  Acquire a CSP context.
-        if(::CryptAcquireContext(
-           &hCryptProv,
-           NULL,
-           NULL,
-           PROV_RSA_FULL,
-           CRYPT_VERIFYCONTEXT) == FALSE)
-        {
-            ThrowException(env, PROVIDER_EXCEPTION, GetLastError());
-            __leave;
-        }
-
         /*
          * If length is negative then use the supplied seed to re-seed the
          * generator and return null.
@@ -330,9 +352,6 @@
 
         if (seedBytes)
             env->ReleaseByteArrayElements(seed, seedBytes, 0); // update orig
-
-        if (hCryptProv)
-            ::CryptReleaseContext(hCryptProv, 0);
     }
 
     return result;

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/sun/security/mscapi/PrngSerialize.java	Mon Dec 03 23:58:15 2018 +0800
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8210476
+ * @requires os.family == "windows"
+ * @summary MSCAPI's PRNG should support serialization
+ * @library /test/lib
+ * @run main PrngSerialize
+ */
+
+import jdk.test.lib.util.SerializationUtils;
+
+import java.security.SecureRandom;
+
+public class PrngSerialize {
+
+    public static void main(String[] args) throws Exception {
+        SecureRandom sr = SecureRandom.getInstance("Windows-PRNG", "SunMSCAPI");
+        sr = (SecureRandom) SerializationUtils.deserialize(SerializationUtils.serialize(sr));
+
+        // This line is likely to release the context in the original sr.
+        System.gc();
+
+        // Make sure the new object is still useable.
+        sr.nextInt();
+    }
+}

--- a/test/jdk/sun/security/mscapi/PrngSlow.java	Mon Dec 03 14:16:39 2018 +0100
+++ b/test/jdk/sun/security/mscapi/PrngSlow.java	Mon Dec 03 23:58:15 2018 +0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2006, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -23,7 +23,7 @@
 
 /**
  * @test
- * @bug 6449335
+ * @bug 6449335 8210476
  * @requires os.family == "windows"
  * @summary MSCAPI's PRNG is too slow
  * @key randomness
@@ -44,7 +44,7 @@
         };
         t = (System.nanoTime() - start) / 1000000000.0;
         System.err.println("\nSpend " + t + " seconds");
-        if (t > 5)
+        if (t > 0.5)
             throw new RuntimeException("Still too slow");
     }
 }