--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/sun/security/rsa/RSAUtil.java	Fri May 11 15:53:12 2018 -0700
@@ -0,0 +1,155 @@
+/*
+ * 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.rsa;
+
+import java.io.IOException;
+import java.security.*;
+import java.security.spec.*;
+import sun.security.util.ObjectIdentifier;
+import sun.security.x509.AlgorithmId;
+
+/**
+ * Utility class for SunRsaSign provider.
+ * Currently used by RSAKeyPairGenerator and RSAKeyFactory.
+ *
+ * @since   11
+ */
+public class RSAUtil {
+
+    public enum KeyType {
+        RSA ("RSA"),
+        PSS ("RSASSA-PSS"),
+        ;
+
+        private final String algo;
+
+        KeyType(String keyAlgo) {
+            this.algo = keyAlgo;
+        }
+        public String keyAlgo() {
+            return algo;
+        }
+        public static KeyType lookup(String name) {
+            for (KeyType kt : KeyType.values()) {
+                if (kt.keyAlgo().equalsIgnoreCase(name)) {
+                    return kt;
+                }
+            }
+            // no match
+            throw new ProviderException("Unsupported algorithm " + name);
+        }
+    }
+
+    public static void checkParamsAgainstType(KeyType type,
+            AlgorithmParameterSpec paramSpec) throws ProviderException {
+        switch (type) {
+            case RSA:
+                if (paramSpec != null) {
+                    throw new ProviderException("null params expected for " +
+                        type.keyAlgo());
+                }
+                break;
+            case PSS:
+                if ((paramSpec != null) &&
+                    !(paramSpec instanceof PSSParameterSpec)) {
+                    throw new ProviderException
+                        ("PSSParmeterSpec expected for " + type.keyAlgo());
+                }
+                break;
+            default:
+                throw new ProviderException
+                    ("Unsupported RSA algorithm " + type);
+        }
+    }
+
+    public static AlgorithmId createAlgorithmId(KeyType type,
+            AlgorithmParameterSpec paramSpec) throws ProviderException {
+
+        checkParamsAgainstType(type, paramSpec);
+
+        ObjectIdentifier oid = null;
+        AlgorithmParameters params = null;
+        try {
+            switch (type) {
+                case RSA:
+                    oid = AlgorithmId.RSAEncryption_oid;
+                    break;
+                case PSS:
+                    if (paramSpec != null) {
+                        params = AlgorithmParameters.getInstance(type.keyAlgo());
+                        params.init(paramSpec);
+                    }
+                    oid = AlgorithmId.RSASSA_PSS_oid;
+                    break;
+                default:
+                    throw new ProviderException
+                        ("Unsupported RSA algorithm "  + type);
+            }
+            AlgorithmId result;
+            if (params == null) {
+                result = new AlgorithmId(oid);
+            } else {
+                result = new AlgorithmId(oid, params);
+            }
+            return result;
+        } catch (NoSuchAlgorithmException | InvalidParameterSpecException e) {
+            // should not happen
+            throw new ProviderException(e);
+        }
+    }
+
+    public static AlgorithmParameterSpec getParamSpec(AlgorithmId algid)
+            throws ProviderException {
+        if (algid == null) {
+            throw new ProviderException("AlgorithmId should not be null");
+        }
+        return getParamSpec(algid.getParameters());
+    }
+
+    public static AlgorithmParameterSpec getParamSpec(AlgorithmParameters params)
+            throws ProviderException {
+        if (params == null) return null;
+
+        String algName = params.getAlgorithm();
+        KeyType type = KeyType.lookup(algName);
+        Class<? extends AlgorithmParameterSpec> specCls;
+        switch (type) {
+            case RSA:
+                throw new ProviderException("No params accepted for " +
+                    type.keyAlgo());
+            case PSS:
+                specCls = PSSParameterSpec.class;
+                break;
+            default:
+                throw new ProviderException("Unsupported RSA algorithm: " + algName);
+        }
+        try {
+            return params.getParameterSpec(specCls);
+        } catch (Exception e) {
+            throw new ProviderException(e);
+        }
+    }
+}