--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/com/sun/crypto/provider/PKCS5Padding.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,128 @@
+/*
+ * Copyright 1997-2007 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package com.sun.crypto.provider;
+
+import javax.crypto.ShortBufferException;
+
+/**
+ * This class implements padding as specified in the PKCS#5 standard.
+ *
+ * @author Gigi Ankeny
+ *
+ *
+ * @see Padding
+ */
+final class PKCS5Padding implements Padding {
+
+    private int blockSize;
+
+    PKCS5Padding(int blockSize) {
+        this.blockSize = blockSize;
+    }
+
+    /**
+     * Adds the given number of padding bytes to the data input.
+     * The value of the padding bytes is determined
+     * by the specific padding mechanism that implements this
+     * interface.
+     *
+     * @param in the input buffer with the data to pad
+     * @param off the offset in <code>in</code> where the padding bytes
+     * are appended
+     * @param len the number of padding bytes to add
+     *
+     * @exception ShortBufferException if <code>in</code> is too small to hold
+     * the padding bytes
+     */
+    public void padWithLen(byte[] in, int off, int len)
+        throws ShortBufferException
+    {
+        if (in == null)
+            return;
+
+        if ((off + len) > in.length) {
+            throw new ShortBufferException("Buffer too small to hold padding");
+        }
+
+        byte paddingOctet = (byte) (len & 0xff);
+        for (int i = 0; i < len; i++) {
+            in[i + off] = paddingOctet;
+        }
+        return;
+    }
+
+    /**
+     * Returns the index where the padding starts.
+     *
+     * <p>Given a buffer with padded data, this method returns the
+     * index where the padding starts.
+     *
+     * @param in the buffer with the padded data
+     * @param off the offset in <code>in</code> where the padded data starts
+     * @param len the length of the padded data
+     *
+     * @return the index where the padding starts, or -1 if the input is
+     * not properly padded
+     */
+    public int unpad(byte[] in, int off, int len) {
+        if ((in == null) ||
+            (len == 0)) { // this can happen if input is really a padded buffer
+            return 0;
+        }
+
+        byte lastByte = in[off + len - 1];
+        int padValue = (int)lastByte & 0x0ff;
+        if ((padValue < 0x01)
+            || (padValue > blockSize)) {
+            return -1;
+        }
+
+        int start = off + len - ((int)lastByte & 0x0ff);
+        if (start < off) {
+            return -1;
+        }
+
+        for (int i = 0; i < ((int)lastByte & 0x0ff); i++) {
+            if (in[start+i] != lastByte) {
+                return -1;
+            }
+        }
+
+        return start;
+    }
+
+    /**
+     * Determines how long the padding will be for a given input length.
+     *
+     * @param len the length of the data to pad
+     *
+     * @return the length of the padding
+     */
+    public int padLength(int len) {
+        int paddingOctet = blockSize - (len % blockSize);
+        return paddingOctet;
+    }
+}