/* |
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* Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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package sun.security.x509; |
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import java.io.IOException; |
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import java.math.BigInteger; |
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import java.security.*; |
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import java.security.interfaces.DSAParams; |
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import sun.security.util.*; |
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/** |
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* This class identifies DSS/DSA Algorithm variants, which are distinguished |
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* by using different algorithm parameters <em>P, Q, G</em>. It uses the |
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* NIST/IETF standard DER encoding. These are used to implement the Digital |
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* Signature Standard (DSS), FIPS 186. |
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* |
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* <P><em><b>NOTE:</b> DSS/DSA Algorithm IDs may be created without these |
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* parameters. Use of DSS/DSA in modes where parameters are |
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* either implicit (e.g. a default applicable to a site or a larger scope), |
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* or are derived from some Certificate Authority's DSS certificate, is |
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* not supported directly. The application is responsible for creating a key |
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* containing the required parameters prior to using the key in cryptographic |
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* operations. The follwoing is an example of how this may be done assuming |
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* that we have a certificate called <code>currentCert</code> which doesn't |
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* contain DSS/DSA parameters and we need to derive DSS/DSA parameters |
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* from a CA's certificate called <code>caCert</code>. |
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* <p> |
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* <code><pre> |
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* // key containing parameters to use |
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* DSAPublicKey cAKey = (DSAPublicKey)(caCert.getPublicKey()); |
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* // key without parameters |
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* DSAPublicKey nullParamsKey = (DSAPublicKey)(currentCert.getPublicKey()); |
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* |
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* DSAParams cAKeyParams = cAKey.getParams(); |
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* KeyFactory kf = KeyFactory.getInstance("DSA"); |
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* DSAPublicKeySpec ks = new DSAPublicKeySpec(nullParamsKey.getY(), |
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* cAKeyParams.getP(), |
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* cAKeyParams.getQ(), |
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* cAKeyParams.getG()); |
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* DSAPublicKey usableKey = kf.generatePublic(ks); |
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* </pre></code> |
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* |
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* @see java.security.interfaces.DSAParams |
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* @see java.security.interfaces.DSAPublicKey |
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* @see java.security.KeyFactory |
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* @see java.security.spec.DSAPublicKeySpec |
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* |
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* @author David Brownell |
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*/ |
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public final |
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class AlgIdDSA extends AlgorithmId implements DSAParams |
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{ |
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private static final long serialVersionUID = 3437177836797504046L; |
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/* |
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* The three unsigned integer parameters. |
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*/ |
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private BigInteger p , q, g; |
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/** Returns the DSS/DSA parameter "P" */ |
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public BigInteger getP () { return p; } |
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/** Returns the DSS/DSA parameter "Q" */ |
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public BigInteger getQ () { return q; } |
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/** Returns the DSS/DSA parameter "G" */ |
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public BigInteger getG () { return g; } |
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/** |
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* Default constructor. The OID and parameters must be |
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* deserialized before this algorithm ID is used. |
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*/ |
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@Deprecated |
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public AlgIdDSA () {} |
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AlgIdDSA (DerValue val) throws IOException |
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{ super(val.getOID()); } |
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/** |
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* Construct an AlgIdDSA from an X.509 encoded byte array. |
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*/ |
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public AlgIdDSA (byte[] encodedAlg) throws IOException |
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{ super (new DerValue(encodedAlg).getOID()); } |
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/** |
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* Constructs a DSS/DSA Algorithm ID from unsigned integers that |
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* define the algorithm parameters. Those integers are encoded |
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* as big-endian byte arrays. |
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* |
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* @param p the DSS/DSA parameter "P" |
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* @param q the DSS/DSA parameter "Q" |
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* @param g the DSS/DSA parameter "G" |
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*/ |
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public AlgIdDSA (byte p [], byte q [], byte g []) |
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throws IOException |
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{ |
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this (new BigInteger (1, p), |
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new BigInteger (1, q), |
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new BigInteger (1, g)); |
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} |
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/** |
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* Constructs a DSS/DSA Algorithm ID from numeric parameters. |
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* If all three are null, then the parameters portion of the algorithm id |
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* is set to null. See note in header regarding use. |
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* |
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* @param p the DSS/DSA parameter "P" |
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* @param q the DSS/DSA parameter "Q" |
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* @param g the DSS/DSA parameter "G" |
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*/ |
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public AlgIdDSA (BigInteger p, BigInteger q, BigInteger g) |
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{ |
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super (DSA_oid); |
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if (p != null || q != null || g != null) { |
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if (p == null || q == null || g == null) |
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throw new ProviderException("Invalid parameters for DSS/DSA" + |
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" Algorithm ID"); |
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try { |
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this.p = p; |
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this.q = q; |
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this.g = g; |
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initializeParams (); |
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} catch (IOException e) { |
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/* this should not happen */ |
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throw new ProviderException ("Construct DSS/DSA Algorithm ID"); |
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} |
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} |
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} |
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/** |
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* Returns "DSA", indicating the Digital Signature Algorithm (DSA) as |
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* defined by the Digital Signature Standard (DSS), FIPS 186. |
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*/ |
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public String getName () |
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{ return "DSA"; } |
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/* |
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* For algorithm IDs which haven't been created from a DER encoded |
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* value, "params" must be created. |
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*/ |
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private void initializeParams () |
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throws IOException |
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{ |
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DerOutputStream out = new DerOutputStream (); |
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out.putInteger(p); |
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out.putInteger(q); |
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out.putInteger(g); |
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params = new DerValue (DerValue.tag_Sequence,out.toByteArray ()); |
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} |
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/** |
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* Parses algorithm parameters P, Q, and G. They're found |
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* in the "params" member, which never needs to be changed. |
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*/ |
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protected void decodeParams () |
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throws IOException |
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{ |
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if (params == null) |
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throw new IOException("DSA alg params are null"); |
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if (params.tag != DerValue.tag_Sequence) |
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throw new IOException("DSA alg parsing error"); |
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params.data.reset (); |
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this.p = params.data.getBigInteger(); |
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this.q = params.data.getBigInteger(); |
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this.g = params.data.getBigInteger(); |
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if (params.data.available () != 0) |
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throw new IOException ("AlgIdDSA params, extra="+ |
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params.data.available ()); |
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} |
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/* |
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* Returns a formatted string describing the parameters. |
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*/ |
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public String toString () |
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{ return paramsToString (); } |
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/* |
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* Returns a string describing the parameters. |
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*/ |
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protected String paramsToString () |
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{ |
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if (params == null) |
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return " null\n"; |
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else |
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return |
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"\n p:\n" + Debug.toHexString(p) + |
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"\n q:\n" + Debug.toHexString(q) + |
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"\n g:\n" + Debug.toHexString(g) + |
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"\n"; |
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} |
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} |