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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

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 * 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

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 * accompanied this code).

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package javax.crypto.spec;

import java.security.spec.AlgorithmParameterSpec;

/**

 * This class specifies an <i>initialization vector</i> (IV).

 * Examples which use IVs are ciphers in feedback mode,

 * e.g., DES in CBC mode and RSA ciphers with OAEP encoding

 * operation.

 *

 * @author Jan Luehe

 *

 * @since 1.4

 */

public class IvParameterSpec implements AlgorithmParameterSpec {

    private byte[] iv;

    /**

     * Creates an IvParameterSpec object using the bytes in <code>iv</code>

     * as the IV.

     *

     * @param iv the buffer with the IV. The contents of the

     * buffer are copied to protect against subsequent modification.

     * @throws NullPointerException if <code>iv</code> is <code>null</code>

     */

    public IvParameterSpec(byte[] iv) {

        this(iv, 0, iv.length);

    }

    /**

     * Creates an IvParameterSpec object using the first <code>len</code>

     * bytes in <code>iv</code>, beginning at <code>offset</code>

     * inclusive, as the IV.

     *

     * <p> The bytes that constitute the IV are those between

     * <code>iv[offset]</code> and <code>iv[offset+len-1]</code> inclusive.

     *

     * @param iv the buffer with the IV. The first <code>len</code>

     * bytes of the buffer beginning at <code>offset</code> inclusive

     * are copied to protect against subsequent modification.

     * @param offset the offset in <code>iv</code> where the IV

     * starts.

     * @param len the number of IV bytes.

     * @throws IllegalArgumentException if <code>iv</code> is <code>null</code>

     * or {@code (iv.length - offset < len)}

     * @throws ArrayIndexOutOfBoundsException is thrown if <code>offset</code>

     * or <code>len</code> index bytes outside the <code>iv</code>.

     */

    public IvParameterSpec(byte[] iv, int offset, int len) {

        if (iv == null) {

            throw new IllegalArgumentException("IV missing");

        }

        if (iv.length - offset < len) {

            throw new IllegalArgumentException

                ("IV buffer too short for given offset/length combination");

        }

        if (len < 0) {

            throw new ArrayIndexOutOfBoundsException("len is negative");

        }

        this.iv = new byte[len];

        System.arraycopy(iv, offset, this.iv, 0, len);

    }

    /**

     * Returns the initialization vector (IV).

     *

     * @return the initialization vector (IV). Returns a new array

     * each time this method is called.

     */

    public byte[] getIV() {

        return this.iv.clone();

    }

}