--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/sun/security/util/SignatureUtil.java	Fri May 11 15:53:12 2018 -0700
@@ -0,0 +1,115 @@
+/*
+ * 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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.
+ */
+
+package sun.security.util;
+
+import java.io.IOException;
+import java.security.*;
+import java.security.spec.*;
+import sun.security.util.ObjectIdentifier;
+import sun.security.x509.AlgorithmId;
+import sun.security.rsa.RSAUtil;
+
+/**
+ * Utility class for Signature related operations. Currently used by various
+ * internal PKI classes such as sun.security.x509.X509CertImpl,
+ * sun.security.pkcs.SignerInfo, for setting signature parameters.
+ *
+ * @since   11
+ */
+public class SignatureUtil {
+
+    // Utility method of creating an AlgorithmParameters object with
+    // the specified algorithm name and encoding
+    private static AlgorithmParameters createAlgorithmParameters(String algName,
+            byte[] paramBytes) throws ProviderException {
+
+        try {
+            AlgorithmParameters result =
+                AlgorithmParameters.getInstance(algName);
+            result.init(paramBytes);
+            return result;
+        } catch (NoSuchAlgorithmException | IOException e) {
+            throw new ProviderException(e);
+        }
+    }
+
+    private static AlgorithmParameterSpec getParamSpec(String sigName,
+            AlgorithmParameters params)
+            throws InvalidAlgorithmParameterException, ProviderException {
+
+        if (params == null) return null;
+
+        if (sigName.toUpperCase().indexOf("RSA") == -1) {
+            throw new ProviderException
+                 ("Unrecognized algorithm for signature parameters " +
+                  sigName);
+        }
+        // AlgorithmParameters.getAlgorithm() may returns oid if it's
+        // created during DER decoding. Convert to use the standard name
+        // before passing it to RSAUtil
+        String alg = params.getAlgorithm();
+        if (alg.equalsIgnoreCase(sigName) || alg.indexOf(".") != -1) {
+            try {
+                params = createAlgorithmParameters(sigName,
+                    params.getEncoded());
+            } catch (IOException e) {
+                throw new ProviderException(e);
+            }
+        }
+        return RSAUtil.getParamSpec(params);
+    }
+
+    // Special method for setting the specified parameter bytes into the
+    // specified Signature object as signature parameters.
+    public static void specialSetParameter(Signature sig, byte[] paramBytes)
+            throws InvalidAlgorithmParameterException, ProviderException {
+
+        AlgorithmParameters params = null;
+        if (paramBytes != null) {
+            String sigName = sig.getAlgorithm();
+            params = createAlgorithmParameters(sigName, paramBytes);
+        }
+        specialSetParameter(sig, params);
+    }
+
+    // Special method for setting the specified AlgorithmParameter object
+    // into the specified Signature object as signature parameters.
+    public static void specialSetParameter(Signature sig,
+            AlgorithmParameters params)
+            throws InvalidAlgorithmParameterException, ProviderException {
+
+        String sigName = sig.getAlgorithm();
+        if (params != null) {
+            sig.setParameter(getParamSpec(sigName, params));
+        } else {
+            try { 
+                sig.setParameter(null);
+            } catch (UnsupportedOperationException e) {
+                // ignore for maintaining backward compatibility
+            }
+        }
+    }
+}