7146728: Inconsistent length for the generated secret using DH key agreement...

7146728: Inconsistent length for the generated secret using DH key agreement impl from SunJCE and PKCS11
Summary: Always return the secret in the same length as the modulus.
Reviewed-by: wetmore

src/share/classes/com/sun/crypto/provider/DHKeyAgreement.java

 /*
- * Copyright (c) 1997, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2012, 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
@@ -33,6 +33,7 @@ import java.security.InvalidKeyException;
 import java.security.Key;
 import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
+import java.security.ProviderException;
 import java.security.spec.AlgorithmParameterSpec;
 import java.security.spec.InvalidKeySpecException;
 import javax.crypto.KeyAgreementSpi;
@@ -234,31 +235,14 @@ extends KeyAgreementSpi {
     protected byte[] engineGenerateSecret()
         throws IllegalStateException
     {
-        if (generateSecret == false) {
-            throw new IllegalStateException
-                ("Key agreement has not been completed yet");
-        }
-
-        // Reset the key agreement here (in case anything goes wrong)
-        generateSecret = false;
-
-        // get the modulus
-        BigInteger modulus = init_p;
-
-        BigInteger tmpResult = y.modPow(x, modulus);
-        byte[] secret = tmpResult.toByteArray();
-
-        /*
-         * BigInteger.toByteArray will sometimes put a sign byte up front, but
-         * we NEVER want one.
-         */
-        if ((tmpResult.bitLength() % 8) == 0) {
-            byte retval[] = new byte[secret.length - 1];
-            System.arraycopy(secret, 1, retval, 0, retval.length);
-            return retval;
-        } else {
-            return secret;
+        int expectedLen = (init_p.bitLength() + 7) >>> 3;
+        byte[] result = new byte[expectedLen];
+        try {
+            engineGenerateSecret(result, 0);
+        } catch (ShortBufferException sbe) {
+            // should never happen since length are identical
         }
+        return result;
     }
 
     /**
@@ -301,39 +285,51 @@ extends KeyAgreementSpi {
         }
 
         BigInteger modulus = init_p;
-        byte[] secret = this.y.modPow(this.x, modulus).toByteArray();
-
-        // BigInteger.toByteArray will sometimes put a sign byte up front,
-        // but we NEVER want one.
-        if ((secret.length << 3) != modulus.bitLength()) {
-            if ((sharedSecret.length - offset) < (secret.length - 1)) {
-                throw new ShortBufferException
+        int expectedLen = (modulus.bitLength() + 7) >>> 3;
+        if ((sharedSecret.length - offset) < expectedLen) {
+            throw new ShortBufferException
                     ("Buffer too short for shared secret");
-            }
-            System.arraycopy(secret, 1, sharedSecret, offset,
-                             secret.length - 1);
-
-            // Reset the key agreement here (not earlier!), so that people
-            // can recover from ShortBufferException above without losing
-            // internal state
-            generateSecret = false;
+        }
 
-            return secret.length - 1;
+        // Reset the key agreement after checking for ShortBufferException
+        // above, so user can recover w/o losing internal state
+        generateSecret = false;
 
+        /*
+         * NOTE: BigInteger.toByteArray() returns a byte array containing
+         * the two's-complement representation of this BigInteger with
+         * the most significant byte is in the zeroth element. This
+         * contains the minimum number of bytes required to represent
+         * this BigInteger, including at least one sign bit whose value
+         * is always 0.
+         *
+         * Keys are always positive, and the above sign bit isn't
+         * actually used when representing keys.  (i.e. key = new
+         * BigInteger(1, byteArray))  To obtain an array containing
+         * exactly expectedLen bytes of magnitude, we strip any extra
+         * leading 0's, or pad with 0's in case of a "short" secret.
+         */
+        byte[] secret = this.y.modPow(this.x, modulus).toByteArray();
+        if (secret.length == expectedLen) {
+            System.arraycopy(secret, 0, sharedSecret, offset,
+                             secret.length);
         } else {
-            if ((sharedSecret.length - offset) < secret.length) {
-                throw new ShortBufferException
-                    ("Buffer too short to hold shared secret");
+            // Array too short, pad it w/ leading 0s
+            if (secret.length < expectedLen) {
+                System.arraycopy(secret, 0, sharedSecret,
+                    offset + (expectedLen - secret.length),
+                    secret.length);
+            } else {
+                // Array too long, check and trim off the excess
+                if ((secret.length == (expectedLen+1)) && secret[0] == 0) {
+                    // ignore the leading sign byte
+                    System.arraycopy(secret, 1, sharedSecret, offset, expectedLen);
+                } else {
+                    throw new ProviderException("Generated secret is out-of-range");
+                }
             }
-            System.arraycopy(secret, 0, sharedSecret, offset, secret.length);
-
-            // Reset the key agreement here (not earlier!), so that people
-            // can recover from ShortBufferException above without losing
-            // internal state
-            generateSecret = false;
-
-            return secret.length;
         }
+        return expectedLen;
     }
 
     /**

src/share/classes/sun/security/pkcs11/P11KeyAgreement.java

 /*
- * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2012, 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
@@ -198,8 +198,22 @@ final class P11KeyAgreement extends KeyAgreementSpi {
             token.p11.C_GetAttributeValue(session.id(), keyID, attributes);
             byte[] secret = attributes[0].getByteArray();
             token.p11.C_DestroyObject(session.id(), keyID);
-            // trim leading 0x00 bytes per JCE convention
-            return P11Util.trimZeroes(secret);
+            // Some vendors, e.g. NSS, trim off the leading 0x00 byte(s) from
+            // the generated secret. Thus, we need to check the secret length
+            // and trim/pad it so the returned value has the same length as
+            // the modulus size
+            if (secret.length == secretLen) {
+                return secret;
+            } else {
+                if (secret.length > secretLen) {
+                    // Shouldn't happen; but check just in case
+                    throw new ProviderException("generated secret is out-of-range");
+                }
+                byte[] newSecret = new byte[secretLen];
+                System.arraycopy(secret, 0, newSecret, secretLen - secret.length,
+                    secret.length);
+                return newSecret;
+            }
         } catch (PKCS11Exception e) {
             throw new ProviderException("Could not derive key", e);
         } finally {

test/com/sun/crypto/provider/KeyAgreement/DHKeyAgreement2.java

 /*
- * Copyright (c) 1997, 2007, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2012, 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 0000000
+ * @bug 7146728
  * @summary DHKeyAgreement2
  * @author Jan Luehe
  */
@@ -52,15 +52,12 @@ import sun.misc.HexDumpEncoder;
 
 public class DHKeyAgreement2 {
 
+    private static final String SUNJCE = "SunJCE";
     private DHKeyAgreement2() {}
 
     public static void main(String argv[]) throws Exception {
             String mode = "USE_SKIP_DH_PARAMS";
 
-            // Add JCE to the list of providers
-            SunJCE jce = new SunJCE();
-            Security.addProvider(jce);
-
             DHKeyAgreement2 keyAgree = new DHKeyAgreement2();
 
             if (argv.length > 1) {
@@ -86,7 +83,7 @@ public class DHKeyAgreement2 {
             // Some central authority creates new DH parameters
             System.err.println("Creating Diffie-Hellman parameters ...");
             AlgorithmParameterGenerator paramGen
-                = AlgorithmParameterGenerator.getInstance("DH");
+                = AlgorithmParameterGenerator.getInstance("DH", SUNJCE);
             paramGen.init(512);
             AlgorithmParameters params = paramGen.generateParameters();
             dhSkipParamSpec = (DHParameterSpec)params.getParameterSpec
@@ -103,7 +100,7 @@ public class DHKeyAgreement2 {
          * above
          */
         System.err.println("ALICE: Generate DH keypair ...");
-        KeyPairGenerator aliceKpairGen = KeyPairGenerator.getInstance("DH");
+        KeyPairGenerator aliceKpairGen = KeyPairGenerator.getInstance("DH", SUNJCE);
         aliceKpairGen.initialize(dhSkipParamSpec);
         KeyPair aliceKpair = aliceKpairGen.generateKeyPair();
         System.out.println("Alice DH public key:\n" +
@@ -112,14 +109,14 @@ public class DHKeyAgreement2 {
                            aliceKpair.getPrivate().toString());
         DHParameterSpec dhParamSpec =
             ((DHPublicKey)aliceKpair.getPublic()).getParams();
-        AlgorithmParameters algParams = AlgorithmParameters.getInstance("DH");
+        AlgorithmParameters algParams = AlgorithmParameters.getInstance("DH", SUNJCE);
         algParams.init(dhParamSpec);
         System.out.println("Alice DH parameters:\n"
                            + algParams.toString());
 
         // Alice executes Phase1 of her version of the DH protocol
         System.err.println("ALICE: Execute PHASE1 ...");
-        KeyAgreement aliceKeyAgree = KeyAgreement.getInstance("DH");
+        KeyAgreement aliceKeyAgree = KeyAgreement.getInstance("DH", SUNJCE);
         aliceKeyAgree.init(aliceKpair.getPrivate());
 
         // Alice encodes her public key, and sends it over to Bob.
@@ -130,7 +127,7 @@ public class DHKeyAgreement2 {
          * in encoded format.
          * He instantiates a DH public key from the encoded key material.
          */
-        KeyFactory bobKeyFac = KeyFactory.getInstance("DH");
+        KeyFactory bobKeyFac = KeyFactory.getInstance("DH", SUNJCE);
         X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec
             (alicePubKeyEnc);
         PublicKey alicePubKey = bobKeyFac.generatePublic(x509KeySpec);
@@ -144,7 +141,7 @@ public class DHKeyAgreement2 {
 
         // Bob creates his own DH key pair
         System.err.println("BOB: Generate DH keypair ...");
-        KeyPairGenerator bobKpairGen = KeyPairGenerator.getInstance("DH");
+        KeyPairGenerator bobKpairGen = KeyPairGenerator.getInstance("DH", SUNJCE);
         bobKpairGen.initialize(dhParamSpec);
         KeyPair bobKpair = bobKpairGen.generateKeyPair();
         System.out.println("Bob DH public key:\n" +
@@ -154,7 +151,7 @@ public class DHKeyAgreement2 {
 
         // Bob executes Phase1 of his version of the DH protocol
         System.err.println("BOB: Execute PHASE1 ...");
-        KeyAgreement bobKeyAgree = KeyAgreement.getInstance("DH");
+        KeyAgreement bobKeyAgree = KeyAgreement.getInstance("DH", SUNJCE);
         bobKeyAgree.init(bobKpair.getPrivate());
 
         // Bob encodes his public key, and sends it over to Alice.
@@ -166,7 +163,7 @@ public class DHKeyAgreement2 {
          * Before she can do so, she has to instanticate a DH public key
          * from Bob's encoded key material.
          */
-        KeyFactory aliceKeyFac = KeyFactory.getInstance("DH");
+        KeyFactory aliceKeyFac = KeyFactory.getInstance("DH", SUNJCE);
         x509KeySpec = new X509EncodedKeySpec(bobPubKeyEnc);
         PublicKey bobPubKey = aliceKeyFac.generatePublic(x509KeySpec);
         System.err.println("ALICE: Execute PHASE2 ...");
@@ -187,50 +184,33 @@ public class DHKeyAgreement2 {
         byte[] aliceSharedSecret = aliceKeyAgree.generateSecret();
         int aliceLen = aliceSharedSecret.length;
 
+        // check if alice's key agreement has been reset afterwards
+        try {
+            aliceKeyAgree.generateSecret();
+            throw new Exception("Error: alice's KeyAgreement not reset");
+        } catch (IllegalStateException e) {
+            System.out.println("EXPECTED:  " + e.getMessage());
+        }
+
         byte[] bobSharedSecret = new byte[aliceLen];
         int bobLen;
         try {
             // provide output buffer that is too short
             bobLen = bobKeyAgree.generateSecret(bobSharedSecret, 1);
-
-            /*
-             * Gatekeeper's note:
-             * We should not be getting here, but every so often, we
-             * get a failure, either a "ShortBufferException" or
-             * "Key agreement has not been completed yet" in the
-             * generateSecret(bobSharedSecret, 0) below.
-             *
-             * This will help to figure out why we're dropping through
-             * and not failing.
-             */
-            System.out.println("NIGHTLY:  Should *NOT* be here!!!\n" +
-                "aliceLen = " + aliceLen + "\n" +
-                "Alice's shared secret");
-
-            try {
-                HexDumpEncoder hd = new HexDumpEncoder();
-
-                hd.encodeBuffer(
-                    new ByteArrayInputStream(aliceSharedSecret), System.out);
-            } catch (IOException e) { }
-
-            System.out.println("bobLen = " + bobLen);
-
-            try {
-                HexDumpEncoder hd = new HexDumpEncoder();
-
-                hd.encodeBuffer(
-                    new ByteArrayInputStream(bobSharedSecret), System.out);
-            } catch (IOException e) { }
-
-            throw new Exception("Shouldn't be succeeding.");
         } catch (ShortBufferException e) {
             System.out.println("EXPECTED:  " + e.getMessage());
         }
-
-        // provide output buffer of required size
+        // retry w/ output buffer of required size
         bobLen = bobKeyAgree.generateSecret(bobSharedSecret, 0);
 
+        // check if bob's key agreement has been reset afterwards
+        try {
+            bobKeyAgree.generateSecret(bobSharedSecret, 0);
+            throw new Exception("Error: bob's KeyAgreement not reset");
+        } catch (IllegalStateException e) {
+            System.out.println("EXPECTED:  " + e.getMessage());
+        }
+
         System.out.println("Alice secret: " + toHexString(aliceSharedSecret));
         System.out.println("Bob secret: " + toHexString(bobSharedSecret));
 

test/sun/security/pkcs11/KeyAgreement/TestInterop.java

+/*
+ * Copyright (c) 2012, 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 7146728
+ * @summary Interop test for DH with secret that has a leading 0x00 byte
+ * @library ..
+ */
+import java.math.BigInteger;
+import java.util.*;
+
+import java.security.*;
+
+import javax.crypto.*;
+import javax.crypto.spec.*;
+
+public class TestInterop extends PKCS11Test {
+
+    private final static BigInteger p = new BigInteger
+    ("171718397966129586011229151993178480901904202533705695869569760169920539"
+    + "80807543778874708672297590042574075430109846864794139516459381007417046"
+    + "27996080624930219892858374168155487210358743785481212360509485282294161"
+    + "39585571568998066586304075565145536350296006867635076744949977849997684"
+    + "222020336013226588207303");
+
+    private final static BigInteger g = new BigInteger("2");
+
+    private final static BigInteger ya = new BigInteger
+    ("687709211571508809414670982463565909269384277848448625781941269577397703"
+    + "73675199968849153119146758339814638228795348558483510369322822476757204"
+    + "22158455966026517829008713407587339322132253724742557954802911059639161"
+    + "24827916158465757962384625410294483756242900146397201260757102085985457"
+    + "09397033481077351036224");
+
+    private final static BigInteger xa = new BigInteger
+    ("104917367119952955556289227181599819745346393858545449202252025137706135"
+    + "98100778613457655440586438263591136003106529323555991109623536177695714"
+    + "66884181531401472902830508361532232717792847436112280721439936797741371"
+    + "245140912614191507");
+
+    private final static BigInteger yb  = new BigInteger
+    ("163887874871842952463100699681506173424091615364591742415764095471629919"
+    + "08421025296419917755446931473037086355546823601999684501737493240373415"
+    + "65608293667837249198973539289354492348897732633852665609611113031379864"
+    + "58514616034107537409230452318065341748503347627733368519091332060477528"
+    + "173423377887175351037810");
+
+    private final static BigInteger xb = new BigInteger
+    ("127757517533485947079959908591028646859165238853082197617179368337276371"
+    + "51601819447716934542027725311863797141734616730248519214531856941516613"
+    + "30313414180008978013330410484011186019824874948204261839391153650949864"
+    + "429505597086564709");
+
+    public void main(Provider prov) throws Exception {
+        if (prov.getService("KeyAgreement", "DH") == null) {
+            System.out.println("DH not supported, skipping");
+            return;
+        }
+        try {
+            System.out.println("testing generateSecret()");
+
+            DHPublicKeySpec publicSpec;
+            DHPrivateKeySpec privateSpec;
+            KeyFactory kf = KeyFactory.getInstance("DH");
+            KeyAgreement ka = KeyAgreement.getInstance("DH", prov);
+            KeyAgreement kbSunJCE = KeyAgreement.getInstance("DH", "SunJCE");
+            DHPrivateKeySpec privSpecA = new DHPrivateKeySpec(xa, p, g);
+            DHPublicKeySpec pubSpecA = new DHPublicKeySpec(ya, p, g);
+            PrivateKey privA = kf.generatePrivate(privSpecA);
+            PublicKey pubA = kf.generatePublic(pubSpecA);
+
+            DHPrivateKeySpec privSpecB = new DHPrivateKeySpec(xb, p, g);
+            DHPublicKeySpec pubSpecB = new DHPublicKeySpec(yb, p, g);
+            PrivateKey privB = kf.generatePrivate(privSpecB);
+            PublicKey pubB = kf.generatePublic(pubSpecB);
+
+            ka.init(privA);
+            ka.doPhase(pubB, true);
+            byte[] n1 = ka.generateSecret();
+
+            kbSunJCE.init(privB);
+            kbSunJCE.doPhase(pubA, true);
+            byte[] n2 = kbSunJCE.generateSecret();
+
+            if (Arrays.equals(n1, n2) == false) {
+                throw new Exception("values mismatch!");
+            } else {
+                System.out.println("values: same");
+            }
+
+            System.out.println("testing generateSecret(byte[], int)");
+            byte[] n3 = new byte[n1.length];
+            ka.init(privB);
+            ka.doPhase(pubA, true);
+            int n3Len = ka.generateSecret(n3, 0);
+            if (n3Len != n3.length) {
+                throw new Exception("PKCS11 Length mismatch!");
+            } else System.out.println("PKCS11 Length: ok");
+            byte[] n4 = new byte[n2.length];
+            kbSunJCE.init(privA);
+            kbSunJCE.doPhase(pubB, true);
+            int n4Len = kbSunJCE.generateSecret(n4, 0);
+            if (n4Len != n4.length) {
+                throw new Exception("SunJCE Length mismatch!");
+            } else System.out.println("SunJCE Length: ok");
+
+            if (Arrays.equals(n3, n4) == false) {
+                throw new Exception("values mismatch! ");
+            } else {
+                System.out.println("values: same");
+            }
+        } catch (Exception ex) {
+            System.out.println("Unexpected ex: " + ex);
+            ex.printStackTrace();
+            throw ex;
+        }
+    }
+
+    public static void main(String[] args) throws Exception {
+        main(new TestInterop());
+    }
+}

test/sun/security/pkcs11/KeyAgreement/TestShort.java

 /*
- * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2012, 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 4942494
+ * @bug 4942494 7146728
  * @summary KAT test for DH (normal and with secret that has leading a 0x00 byte)
  * @author Andreas Sterbenz
  * @library ..
@@ -66,7 +66,7 @@ public class TestShort extends PKCS11Test {
     ("433011588852527167500079509018272713204454720683");
 
     private final static byte[] s2 = parse
-    ("19:c7:f1:bb:2e:3d:93:fa:02:d2:e9:9f:75:32:b9:e6:7a:a0:4a:10:45:81:d4:2b:"
+    ("00:19:c7:f1:bb:2e:3d:93:fa:02:d2:e9:9f:75:32:b9:e6:7a:a0:4a:10:45:81:d4:2b:"
     + "e2:77:4c:70:41:39:7c:19:fa:65:64:47:49:8a:ad:0a:fa:9d:e9:62:68:97:c5:52"
     + ":b1:37:03:d9:cd:aa:e1:bd:7e:71:0c:fc:15:a1:95");
 
@@ -88,31 +88,36 @@ public class TestShort extends PKCS11Test {
             System.out.println("DH not supported, skipping");
             return;
         }
-        DHPublicKeySpec publicSpec;
-        DHPrivateKeySpec privateSpec;
-        KeyFactory kf = KeyFactory.getInstance("DH", provider);
-        KeyAgreement ka = KeyAgreement.getInstance("DH", provider);
-//      KeyAgreement ka = KeyAgreement.getInstance("DH");
-
-        PrivateKey pr1 = kf.generatePrivate(new DHPrivateKeySpec(x1, p, g));
-        PublicKey pu2 = kf.generatePublic(new DHPublicKeySpec(y2, p, g));
-        PublicKey pu3 = kf.generatePublic(new DHPublicKeySpec(y3, p, g));
-
-        ka.init(pr1);
-        ka.doPhase(pu2, true);
-        byte[] n2 = ka.generateSecret();
-        if (Arrays.equals(s2, n2) == false) {
-            throw new Exception("mismatch 2");
-        }
-        System.out.println("short ok");
+        try {
+            DHPublicKeySpec publicSpec;
+            DHPrivateKeySpec privateSpec;
+            KeyFactory kf = KeyFactory.getInstance("DH", provider);
+            KeyAgreement ka = KeyAgreement.getInstance("DH", provider);
+
+            PrivateKey pr1 = kf.generatePrivate(new DHPrivateKeySpec(x1, p, g));
+            PublicKey pu2 = kf.generatePublic(new DHPublicKeySpec(y2, p, g));
+            PublicKey pu3 = kf.generatePublic(new DHPublicKeySpec(y3, p, g));
+
+            ka.init(pr1);
+            ka.doPhase(pu2, true);
+            byte[] n2 = ka.generateSecret();
+            if (Arrays.equals(s2, n2) == false) {
+                throw new Exception("mismatch 2");
+            }
+            System.out.println("short ok");
 
-        ka.init(pr1);
-        ka.doPhase(pu3, true);
-        byte[] n3 = ka.generateSecret();
-        if (Arrays.equals(s3, n3) == false) {
-            throw new Exception("mismatch 3");
+            ka.init(pr1);
+            ka.doPhase(pu3, true);
+            byte[] n3 = ka.generateSecret();
+            if (Arrays.equals(s3, n3) == false) {
+                throw new Exception("mismatch 3");
+            }
+            System.out.println("normal ok");
+        } catch (Exception ex) {
+            System.out.println("Unexpected Exception: " + ex);
+            ex.printStackTrace();
+            throw ex;
         }
-        System.out.println("normal ok");
 
 /*
         KeyPairGenerator kpg = KeyPairGenerator.getInstance("DH", provider);