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    1   /*
    2    * Copyright (c) 1997, 2007, 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 javax.crypto.spec;
   27   
   28   import java.security.spec.AlgorithmParameterSpec;
   29   
   30   /**
   31    * This class specifies an <i>initialization vector</i> (IV).
   32    * Examples which use IVs are ciphers in feedback mode,
   33    * e.g., DES in CBC mode and RSA ciphers with OAEP encoding
   34    * operation.
   35    *
   36    * @author Jan Luehe
   37    *
   38    * @since 1.4
   39    */
   40   public class IvParameterSpec implements AlgorithmParameterSpec {
   41   
   42       private byte[] iv;
   43   
   44       /**
   45        * Creates an IvParameterSpec object using the bytes in <code>iv</code>
   46        * as the IV.
   47        *
   48        * @param iv the buffer with the IV. The contents of the
   49        * buffer are copied to protect against subsequent modification.
   50        * @throws NullPointerException if <code>iv</code> is <code>null</code>
   51        */
   52       public IvParameterSpec(byte[] iv) {
   53           this(iv, 0, iv.length);
   54       }
   55   
   56       /**
   57        * Creates an IvParameterSpec object using the first <code>len</code>
   58        * bytes in <code>iv</code>, beginning at <code>offset</code>
   59        * inclusive, as the IV.
   60        *
   61        * <p> The bytes that constitute the IV are those between
   62        * <code>iv[offset]</code> and <code>iv[offset+len-1]</code> inclusive.
   63        *
   64        * @param iv the buffer with the IV. The first <code>len</code>
   65        * bytes of the buffer beginning at <code>offset</code> inclusive
   66        * are copied to protect against subsequent modification.
   67        * @param offset the offset in <code>iv</code> where the IV
   68        * starts.
   69        * @param len the number of IV bytes.
   70        * @throws IllegalArgumentException if <code>iv</code> is <code>null</code>
   71        * or <code>(iv.length - offset < len)</code>
   72        * @throws ArrayIndexOutOfBoundsException is thrown if <code>offset</code>
   73        * or <code>len</code> index bytes outside the <code>iv</code>.
   74        */
   75       public IvParameterSpec(byte[] iv, int offset, int len) {
   76           if (iv == null) {
   77               throw new IllegalArgumentException("IV missing");
   78           }
   79           if (iv.length - offset < len) {
   80               throw new IllegalArgumentException
   81                   ("IV buffer too short for given offset/length combination");
   82           }
   83           if (len < 0) {
   84               throw new ArrayIndexOutOfBoundsException("len is negative");
   85           }
   86           this.iv = new byte[len];
   87           System.arraycopy(iv, offset, this.iv, 0, len);
   88       }
   89   
   90       /**
   91        * Returns the initialization vector (IV).
   92        *
   93        * @return the initialization vector (IV). Returns a new array
   94        * each time this method is called.
   95        */
   96       public byte[] getIV() {
   97           return (byte[])this.iv.clone();
   98       }
   99   }

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