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    1   /*
    2    * Copyright (c) 2001, 2006, Oracle and/or its affiliates. All rights reserved.
    3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
    4    *
    5    * This code is free software; you can redistribute it and/or modify it
    6    * under the terms of the GNU General Public License version 2 only, as
    7    * published by the Free Software Foundation.  Oracle designates this
    8    * particular file as subject to the "Classpath" exception as provided
    9    * by Oracle in the LICENSE file that accompanied this code.
   10    *
   11    * This code is distributed in the hope that it will be useful, but WITHOUT
   12    * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   13    * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   14    * version 2 for more details (a copy is included in the LICENSE file that
   15    * accompanied this code).
   16    *
   17    * You should have received a copy of the GNU General Public License version
   18    * 2 along with this work; if not, write to the Free Software Foundation,
   19    * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   20    *
   21    * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   22    * or visit www.oracle.com if you need additional information or have any
   23    * questions.
   24    */
   25   
   26   package java.security.spec;
   27   
   28   import java.math.BigInteger;
   29   import java.security.spec.MGF1ParameterSpec;
   30   
   31   /**
   32    * This class specifies a parameter spec for RSA-PSS signature scheme,
   33    * as defined in the
   34    * <a href="http://www.ietf.org/rfc/rfc3447.txt">PKCS#1 v2.1</a>
   35    * standard.
   36    *
   37    * <p>Its ASN.1 definition in PKCS#1 standard is described below:
   38    * <pre>
   39    * RSASSA-PSS-params ::= SEQUENCE {
   40    *   hashAlgorithm      [0] OAEP-PSSDigestAlgorithms  DEFAULT sha1,
   41    *   maskGenAlgorithm   [1] PKCS1MGFAlgorithms  DEFAULT mgf1SHA1,
   42    *   saltLength         [2] INTEGER  DEFAULT 20,
   43    *   trailerField       [3] INTEGER  DEFAULT 1
   44    * }
   45    * </pre>
   46    * where
   47    * <pre>
   48    * OAEP-PSSDigestAlgorithms    ALGORITHM-IDENTIFIER ::= {
   49    *   { OID id-sha1 PARAMETERS NULL   }|
   50    *   { OID id-sha256 PARAMETERS NULL }|
   51    *   { OID id-sha384 PARAMETERS NULL }|
   52    *   { OID id-sha512 PARAMETERS NULL },
   53    *   ...  -- Allows for future expansion --
   54    * }
   55    *
   56    * PKCS1MGFAlgorithms    ALGORITHM-IDENTIFIER ::= {
   57    *   { OID id-mgf1 PARAMETERS OAEP-PSSDigestAlgorithms },
   58    *   ...  -- Allows for future expansion --
   59    * }
   60    * </pre>
   61    * <p>Note: the PSSParameterSpec.DEFAULT uses the following:
   62    *     message digest  -- "SHA-1"
   63    *     mask generation function (mgf) -- "MGF1"
   64    *     parameters for mgf -- MGF1ParameterSpec.SHA1
   65    *     SaltLength   -- 20
   66    *     TrailerField -- 1
   67    *
   68    * @see MGF1ParameterSpec
   69    * @see AlgorithmParameterSpec
   70    * @see java.security.Signature
   71    *
   72    * @author Valerie Peng
   73    *
   74    *
   75    * @since 1.4
   76    */
   77   
   78   public class PSSParameterSpec implements AlgorithmParameterSpec {
   79   
   80       private String mdName = "SHA-1";
   81       private String mgfName = "MGF1";
   82       private AlgorithmParameterSpec mgfSpec = MGF1ParameterSpec.SHA1;
   83       private int saltLen = 20;
   84       private int trailerField = 1;
   85   
   86       /**
   87        * The PSS parameter set with all default values.
   88        * @since 1.5
   89        */
   90       public static final PSSParameterSpec DEFAULT = new PSSParameterSpec();
   91   
   92       /**
   93        * Constructs a new <code>PSSParameterSpec</code> as defined in
   94        * the PKCS #1 standard using the default values.
   95        */
   96       private PSSParameterSpec() {
   97       }
   98   
   99       /**
  100        * Creates a new <code>PSSParameterSpec</code> as defined in
  101        * the PKCS #1 standard using the specified message digest,
  102        * mask generation function, parameters for mask generation
  103        * function, salt length, and trailer field values.
  104        *
  105        * @param mdName the algorithm name of the hash function.
  106        * @param mgfName the algorithm name of the mask generation
  107        * function.
  108        * @param mgfSpec the parameters for the mask generation
  109        * function. If null is specified, null will be returned by
  110        * getMGFParameters().
  111        * @param saltLen the length of salt.
  112        * @param trailerField the value of the trailer field.
  113        * @exception NullPointerException if <code>mdName</code>,
  114        * or <code>mgfName</code> is null.
  115        * @exception IllegalArgumentException if <code>saltLen</code>
  116        * or <code>trailerField</code> is less than 0.
  117        * @since 1.5
  118        */
  119       public PSSParameterSpec(String mdName, String mgfName,
  120                               AlgorithmParameterSpec mgfSpec,
  121                               int saltLen, int trailerField) {
  122           if (mdName == null) {
  123               throw new NullPointerException("digest algorithm is null");
  124           }
  125           if (mgfName == null) {
  126               throw new NullPointerException("mask generation function " +
  127                                              "algorithm is null");
  128           }
  129           if (saltLen < 0) {
  130               throw new IllegalArgumentException("negative saltLen value: " +
  131                                                  saltLen);
  132           }
  133           if (trailerField < 0) {
  134               throw new IllegalArgumentException("negative trailerField: " +
  135                                                  trailerField);
  136           }
  137           this.mdName = mdName;
  138           this.mgfName = mgfName;
  139           this.mgfSpec = mgfSpec;
  140           this.saltLen = saltLen;
  141           this.trailerField = trailerField;
  142       }
  143   
  144       /**
  145        * Creates a new <code>PSSParameterSpec</code>
  146        * using the specified salt length and other default values as
  147        * defined in PKCS#1.
  148        *
  149        * @param saltLen the length of salt in bits to be used in PKCS#1
  150        * PSS encoding.
  151        * @exception IllegalArgumentException if <code>saltLen</code> is
  152        * less than 0.
  153        */
  154       public PSSParameterSpec(int saltLen) {
  155           if (saltLen < 0) {
  156               throw new IllegalArgumentException("negative saltLen value: " +
  157                                                  saltLen);
  158           }
  159           this.saltLen = saltLen;
  160       }
  161   
  162       /**
  163        * Returns the message digest algorithm name.
  164        *
  165        * @return the message digest algorithm name.
  166        * @since 1.5
  167        */
  168       public String getDigestAlgorithm() {
  169           return mdName;
  170       }
  171   
  172       /**
  173        * Returns the mask generation function algorithm name.
  174        *
  175        * @return the mask generation function algorithm name.
  176        *
  177        * @since 1.5
  178        */
  179       public String getMGFAlgorithm() {
  180           return mgfName;
  181       }
  182   
  183       /**
  184        * Returns the parameters for the mask generation function.
  185        *
  186        * @return the parameters for the mask generation function.
  187        * @since 1.5
  188        */
  189       public AlgorithmParameterSpec getMGFParameters() {
  190           return mgfSpec;
  191       }
  192   
  193       /**
  194        * Returns the salt length in bits.
  195        *
  196        * @return the salt length.
  197        */
  198       public int getSaltLength() {
  199           return saltLen;
  200       }
  201   
  202       /**
  203        * Returns the value for the trailer field, i.e. bc in PKCS#1 v2.1.
  204        *
  205        * @return the value for the trailer field, i.e. bc in PKCS#1 v2.1.
  206        * @since 1.5
  207        */
  208       public int getTrailerField() {
  209           return trailerField;
  210       }
  211   }

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