cipher.java

jpeg2000编解码

    /**
     * Encrypts or decrypts the specified subarray of data, which is not the
     * final data in this stream, and places the result in the specified
     * output buffer (starting at offset 0). For block ciphers, if the last
     * block so far is incomplete, it will be buffered and processed in
     * subsequent calls to <code>update</code> or <code>crypt</code>.
     * <p>
     * Whether the data is encrypted or decrypted depends on the cipher's
     * initialization state. <code>out.length</code> must be at least
     * <code>outBufferSize(inLen)</code>, otherwise an
     * ArrayIndexOutOfBoundsException will be thrown (in this case it is
     * not specified how much, if any, of the output will have been written).
     * <p>
     * <strong><a href="../guide/ijce/JCEDifferences.html">This method
     * is not supported in JavaSoft's version of JCE.</a></strong> However,
     * an equivalent method is declared in the JCE 1.2 preview documentation
     * for <samp>javax.crypto.Cipher</samp>.
     *
     * @param  in           the input data.
     * @param  inOffset     the offset indicating where the subarray starts in
     *                      the <i>in</i> array.
     * @param  inLen        the length of the subarray.
     * @param  out          the output buffer.
     * @return the number of bytes written.
     * @exception NullPointerException if in == null || out == null
     * @exception IllegalArgumentException if inLen < 0
     * @exception ArrayIndexOutOfBoundsException if inOffset < 0 ||
     *                      outOffset < 0 || (long) inOffset + inLen > in.length ||
     *                      outBufferSize(inLen) > out.length
     */
    public final int
    update (byte[] in, int inOffset, int inLen, byte[] out) {
        return updateInternal(in, inOffset, inLen, out, 0, false);
    }

    /**
     * Encrypts or decrypts the specified subarray of data, which is not the
     * final data in this stream, and places the result in the specified
     * output buffer. For block ciphers, if the last block so far is
     * incomplete, it will be buffered and processed in subsequent calls to
     * <code>update</code> or <code>crypt</code>.
     * <p>
     * Whether the data is encrypted or decrypted depends on the cipher's
     * initialization state. <code>out.length</code> must be at least
     * <code>(long) outOffset + outBufferSize(inLen)</code>, otherwise an
     * ArrayIndexOutOfBoundsException will be thrown (in this case it is
     * not specified how much, if any, of the output will have been written).
     * <p>
     * <strong><a href="../guide/ijce/JCEDifferences.html">This method
     * is not supported in JavaSoft's version of JCE.</a></strong> However,
     * an equivalent method is declared in the JCE 1.2 preview documentation
     * for <samp>javax.crypto.Cipher</samp>.
     *
     * @param  in           the input data.
     * @param  inOffset     the offset indicating where the subarray starts in
     *                      the <i>in</i> array.
     * @param  inLen        the length of the subarray.
     * @param  out          the output buffer.
     * @param  outOffset    the offset indicating where to start writing the
     *                      result into the output buffer.
     * @return the number of bytes written.
     * @exception NullPointerException if in == null || out == null
     * @exception IllegalArgumentException if inLen < 0
     * @exception ArrayIndexOutOfBoundsException if inOffset < 0 ||
     *                      outOffset < 0 || (long) inOffset + inLen > in.length ||
     *                      (long) outOffset + outBufferSize(inLen) > out.length
     */
    public final int
    update (byte[] in, int inOffset, int inLen, byte[] out, int outOffset) {
        return updateInternal(in, inOffset, inLen, out, outOffset, false);
    }

    /**
     * Encrypts or decrypts the specified array of data, which will be
     * automatically padded/unpadded as necessary.
     * <p>
     * Whether the data is encrypted or decrypted depends on the cipher's
     * initialization state. This method will automatically allocate
     * an output buffer of the right size.
     * <p>
     * If the final block is incomplete, the cipher must have a padding scheme
     * other than "NONE", and it must be in the ENCRYPT state. If this is not
     * the case, an IllegalBlockSizeException will be thrown.
     * <p>
     * If the cipher is in the DECRYPT state and padding is being used,
     * at least one full ciphertext block should be passed to <code>crypt</code>.
     * This is necessary because the last block contains information needed to
     * determine the length of the original plaintext.
     *
     * @param  in   the input data.
     * @return the encryption or decryption result.
     * @exception NullPointerException if in == null
     * @exception IllegalBlockSizeException if the final block cannot be
     *              padded or unpadded.
     */
    public final byte[] crypt(byte[] in)
    throws IllegalBlockSizeException {
        return crypt(in, 0, in.length);
    }

    /**
     * Encrypts or decrypts the specified array of data, which will be
     * automatically padded/unpadded as necessary.
     * <p>
     * Whether the data is encrypted or decrypted depends on the cipher's
     * initialization state. This method will automatically allocate 
     * an output buffer of the right size.
     * <p>
     * If the final block is incomplete, the cipher must have a padding scheme
     * other than "NONE", and it must be in the ENCRYPT state. If this is not
     * the case, an IllegalBlockSizeException will be thrown.
     * <p>
     * If the cipher is in the DECRYPT state and padding is being used,
     * at least one full ciphertext block should be passed to <code>crypt</code>.
     * This is necessary because the last block contains information needed to
     * determine the length of the original plaintext.
     *
     * @param  in      the input data.
     * @param  offset  the offset indicating where the subarray starts in the
     *                 <i>in</i> array.
     * @param  length  the length of the subarray.
     * @return the encryption or decryption result.
     * @exception NullPointerException if in == null
     * @exception IllegalArgumentException if length < 0
     * @exception ArrayIndexOutOfBoundsException if offset < 0 ||
     *                 (long) offset + length > in.length
     * @exception IllegalBlockSizeException if the final block cannot be padded
     *                 or unpadded.
     */
    public final byte[] crypt(byte[] in, int offset, int length)
    throws IllegalBlockSizeException {
        byte[] out = new byte[outBufferSizeInternal(length, true)];
        int outlen = updateInternal(in, offset, length, out, 0, true);
        if (outlen != out.length) {
            byte[] newout = new byte[outlen];
            System.arraycopy(out, 0, newout, 0, outlen);
            return newout;
        } else
            return out;
    }

    /**
     * Encrypts or decrypts the specified subarray of data, pads or unpads
     * it as necessary, and places the result in the specified output buffer.
     * <p>
     * Whether the data is encrypted or decrypted depends on the cipher's
     * initialization state.
     * <p>
     * If the final block is incomplete, the cipher must have a padding scheme
     * other than "NONE", and it must be in the ENCRYPT state. If this is not
     * the case, an IllegalBlockSizeException will be thrown.
     * <p>
     * If the cipher is in the DECRYPT state and padding is being used,
     * at least one full ciphertext block should be passed to <code>crypt</code>.
     * This is necessary because the last block contains information needed to
     * determine the length of the original plaintext.
     *
     * @param  in           the input data.
     * @param  inOffset     the offset indicating where the subarray starts in
     *                      the <i>in</i> array.
     * @param  inLen        the length of the subarray.
     * @param  out          the output buffer.
     * @param  outOffset    the offset indicating where to start writing the
     *                      result into the output buffer.
     * @return the number of bytes written.
     * @exception NullPointerException if in == null || out == null
     * @exception IllegalArgumentException if inLen < 0
     * @exception ArrayIndexOutOfBoundsException if inOffset < 0 ||
     *                      outOffset < 0 || (long) inOffset + inLen > in.length ||
     *                      (long) outOffset + outBufferSize(inLen) > out.length
     */
    public final int
    crypt(byte[] in, int inOffset, int inLen, byte[] out, int outOffset)
    throws IllegalBlockSizeException {
        return updateInternal(in, inOffset, inLen, out, outOffset, true);
    }

    /**
     * Equivalent to <code>crypt(in)</code>.
     * <p>
     * <strong><a href="../guide/ijce/JCEDifferences.html">This method
     * is not supported in JavaSoft's version of JCE.</a></strong> However,
     * an equivalent method is declared in the JCE 1.2 preview documentation
     * for <samp>javax.crypto.Cipher</samp>.
     */
    public final byte[] doFinal(byte[] in)
    throws IllegalBlockSizeException {
        return crypt(in, 0, in.length);
    }

    /**
     * Equivalent to <code>crypt(in, offset, length)</code>.
     * <p>
     * <strong><a href="../guide/ijce/JCEDifferences.html">This method
     * is not supported in JavaSoft's version of JCE.</a></strong> However,
     * an equivalent method is declared in the JCE 1.2 preview documentation
     * for <samp>javax.crypto.Cipher</samp>.
     */
    public final byte[] doFinal(byte[] in, int offset, int length)
    throws IllegalBlockSizeException {
        return crypt(in, offset, length);
    }

    /**
     * Equivalent to <code>crypt(in, inOffset, inLen, out, 0)</code>.
     * <p>
     * <strong><a href="../guide/ijce/JCEDifferences.html">This method
     * is not supported in JavaSoft's version of JCE.</a></strong> However,
     * an equivalent method is declared in the JCE 1.2 preview documentation
     * for <samp>javax.crypto.Cipher</samp>.
     */
    public final int
    doFinal(byte[] in, int inOffset, int inLen, byte[] out)
    throws IllegalBlockSizeException {
        return crypt(in, inOffset, inLen, out, 0);
    }

    /**
     * Equivalent to <code>crypt(in, inOffset, inLen, out, outOffset)</code>.
     * <p>
     * <strong><a href="../guide/ijce/JCEDifferences.html">This method
     * is not supported in JavaSoft's version of JCE.</a></strong> However,
     * an equivalent method is declared in the JCE 1.2 preview documentation
     * for <samp>javax.crypto.Cipher</samp>.
     */
    public final int
    doFinal(byte[] in, int inOffset, int inLen, byte[] out, int outOffset)
    throws IllegalBlockSizeException {
        return crypt(in, inOffset, inLen, out, outOffset);
    }

    /**
     * Internal method to take into account padding and buffering before
     * calling engineOutBufferSize. (engineOutBufferSize should not be
     * called other than via this method).
     *
     * @param inLen     the number of bytes of input
     * @param isFinal   whether the last block is to be padded
     * @return the length in bytes of the output block
     * @exception IllegalArgumentException if inLen < 0
     */
    private int outBufferSizeInternal(int inLen, boolean isFinal) {
        if (inLen < 0) throw new IllegalArgumentException("inLen < 0");
        if (!implBuffering) {
            inLen += buffered;
            int remainder = inLen % inputSize;
            inLen -= remainder;
            if (isFinal && state == ENCRYPT &&
                (padding != null || remainder > 0))
                inLen += inputSize;
        }
        if (inLen < 0) IJCE.reportBug("inLen < 0");
        if (tracing) traceMethod("engineOutBufferSize(" + inLen + ", " + isFinal + ")");
        int result = engineOutBufferSize(inLen, isFinal);
        if (tracing) traceResult(result);
        return result;
    }

    /**
     * Internal method to take into account padding and buffering before
     * calling engineInBufferSize. (engineInBufferSize should not be
     * called other than via this method).
     *
     * @param outLen    the number of bytes of output
     * @param isFinal   whether the last block is to be padded
     * @return the minimum number of bytes of input
     * @exception IllegalArgumentException if outLen < 0
     */
    private int inBufferSizeInternal(int outLen, boolean isFinal) {
        if (!implBuffering) {
            int remainder = outLen % outputSize;
            if (remainder > 0) outLen += outputSize - remainder;
        }
        if (tracing) traceMethod("engineInBufferSize(" + outLen + ", " + isFinal + ")");
        int result = engineInBufferSize(outLen, isFinal);
        if (tracing) traceResult(result);
        if (!implBuffering) {
            if (isFinal && state == ENCRYPT && padding != null)
                result -= inputSize;
            result -= buffered;
        }
        if (result < 0) result = 0;
        return result;
    }

    /**
     * This method handles buffering, padding, and calling the cipher's
     * engineUpdate and engineCrypt methods.
     */
    private int updateInternal(byte[] in, int inOffset, int inLen, byte[] out,
                               int outOffset, boolean isFinal) {
if (DEBUG && debuglevel >= 5 && tracing) traceMethod("updateInternal(<" + dump(in) + ">, " + inOffset + ", " + inLen + ", <" + dump(out) + ">, " + outOffset + ", " + isFinal + ")");
boolean exception = false;
int outStart = outOffset;
try {

        if (state == UNINITIALIZED) throw new IllegalStateException("cipher uninitialized");
        if (inLen < 0) throw new IllegalArgumentException("inLen < 0");
        if (inOffset < 0 || outOffset < 0 || (long)inOffset+inLen > in.length) {
if (DEBUG && debuglevel >= 1) debug("inOffset = " + inOffset + ", inLen = " + inLen + ", outOffset = " + outOffset + ", in.length = " + in.length);
            throw new ArrayIndexOutOfBoundsException(
                "inOffset < 0  || outOffset < 0 || (long)inOffset+inLen > in.length");
        }
        // if (in == null) exception has already been thrown.