/*
*
*
* Copyright 1990-2007 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program 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.
*
* This program 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 at /legal/license.txt).
*
* 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 or visit www.sun.com if you need additional
* information or have any questions.
*/
package com.sun.midp.crypto;
/**
* This class implements RSA encryption/decryption
*/
public final class RSA extends Cipher {
/** Local certificate key. */
private RSAKey ckey = null;
/** Current cipher mode. */
private int mode;
/** Local random number for seed. */
private static SecureRandom rnd = null;
/** Signature pad offset. */
private final static int PAD_OFFSET = 2;
/** Message to sign. */
private byte[] messageToSign;
/** Number of bytes in the message to sign. */
private int bytesInMessage;
/**
* A native method for performing modular exponentiation.
*
* @param data contains the data on which exponentiation is to
* be performed
* @param exponent contains the exponent, e.g. 65537 (decimal) is
* written as a three-byte array containing
* 0x01, 0x00, 0x01
* @param modulus contains the modulus
* @param result the result of the modular exponentiation is
* returned in this array
* @return length of the result in bytes
* @exception IllegalArgumentException if a argument is too long for
* the native code to handle. (currently (32K - 8) bits max)
*/
private static native int modExp(byte[] data, byte[] exponent,
byte[] modulus, byte[] result)
throws IllegalArgumentException;
/**
* Performs an RSA operation on specified data. If the data length
* is not the same as the modulus length (as may happen for an
* encryption request), PKCS#1 block type 2 padding is added.
* <P />
* @param data byte array to be encrypted/decrypted
* @return a byte array containing the result
* @exception IllegalStateException
* if the encryption/decryption key is missing a modulus or
* exponent
*/
private byte[] doIt(byte[] data) {
int modLen = ckey.getModulusLen();
byte[] buf = new byte[modLen];
byte[] mod = new byte[modLen];
int bufLen;
// Note: Both RSAPublicKey and RSAPrivateKey provide the same
// interface
short val = ckey.getModulus(mod, (short) 0);
byte[] tmp = new byte[modLen];
val = ckey.getExponent(tmp, (short) 0);
byte[] exp = new byte [val];
System.arraycopy(tmp, 0, exp, 0, val);
bufLen = modExp(data, exp, mod, buf);
if (bufLen == modLen) {
return buf;
} else if (bufLen < modLen) {
// Reuse tmp which already points to a byte array of modLen size
for (int i = 0; i < modLen; i++) tmp[i] = 0;
if (buf[0] == (byte) 0x01) {
tmp[0] = (byte) 0x00;
tmp[1] = (byte) 0x01;
for (int i = 2; i < modLen - bufLen + 1; i++) {
tmp[i] = (byte) 0xff;
}
System.arraycopy(buf, 1, tmp,
modLen - bufLen + 1, (bufLen - 1));
} else {
System.arraycopy(buf, 0, tmp, (modLen - bufLen), bufLen);
}
return tmp;
} else { // bufLen > modLen, key may be too long
throw new IllegalArgumentException("Key too long");
}
}
/**
* Constructor for RSA.
*
* @exception RuntimeException if the random number generator can't be
* created
*/
public RSA() {
mode = Cipher.MODE_UNINITIALIZED;
try {
rnd = SecureRandom.getInstance(SecureRandom.ALG_SECURE_RANDOM);
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("Random number generator missing");
}
}
/**
* Called by the factory method to set the mode and padding parameters.
* Need because Class.newInstance does not take args.
*
* @param mode the mode parsed from the transformation parameter of
* getInstance and upper cased
* @param padding the padding parsed from the transformation parameter of
* getInstance and upper cased
*
* @exception NoSuchPaddingException if <code>transformation</code>
* contains a padding scheme that is not available.
* @exception IllegalArgumentException if mode is incorrect
*/
protected void setChainingModeAndPadding(String mode, String padding)
throws NoSuchPaddingException {
if (!(mode.equals("") || mode.equals("NONE"))) {
throw new IllegalArgumentException("illegal chaining mode");
}
// NOPADDING is not an option.
if (!(padding.equals("") || padding.equals("PKCS1PADDING"))) {
throw new NoSuchPaddingException();
}
}
/**
* Initializes this cipher with a key and a set of algorithm
* parameters.
*
* @param opMode the operation mode of this cipher
* @param key the encryption key
* @param params the algorithm parameters
*
* @exception java.security.InvalidKeyException if the given key
* is inappropriate for initializing this cipher
* @exception java.security.InvalidAlgorithmParameterException
* if the given algorithm parameters are inappropriate for this cipher
* @exception IllegalArgumentException if opMode is incorrect
*/
public void init(int opMode, Key key, CryptoParameter params)
throws InvalidKeyException, InvalidAlgorithmParameterException {
if (!(key instanceof RSAKey)) {
throw new InvalidKeyException();
}
if (opMode != DECRYPT_MODE && opMode != ENCRYPT_MODE) {
throw new IllegalArgumentException("Wrong operation mode");
}
mode = opMode;
ckey = (RSAKey)key;
if (ckey.getModulusLen() == 0) {
throw new InvalidKeyException();
}
messageToSign = new byte[ckey.getModulusLen()];
bytesInMessage = 0;
}
/**
* Fills the internal buffer to be encrypted or decrypted
* (depending on how this cipher was initialized).
* For the RSA public key cipher there is no output until doFinal.
*
* @param inBuf the input buffer
* @param inOff the offset in <code>input</code> where the input
* starts
* @param inLen the input length
* @param outBuf the buffer for the result
* @param outOff the offset in <code>output</code> where the result
* is stored
*
* @return the number of bytes stored in <code>output</code>
*
* @exception IllegalStateException if this cipher is in a wrong state
* (e.g., has not been initialized)
* @exception ShortBufferException if the given output buffer is too small
* to hold the result
* @exception IllegalArgumentException if a length or offset is incorrect
*/
public int update(byte inBuf[], int inOff, int inLen,
byte outBuf[], int outOff)
throws IllegalStateException, ShortBufferException {
addToMessage(inBuf, inOff, inLen);
return 0;
}
/**
* Fills the internal message buffer to be encrypted or decrypted
* (depending on how this cipher was initialized).
* For the RSA public key cipher there is no output until doFinal.
*
* @param inBuf the input buffer
* @param inOff the offset in <code>input</code> where the input
* starts
* @param inLen the input length
*
* @exception IllegalStateException if this cipher is in a wrong state
* (e.g., has not been initialized)
* @exception IllegalArgumentException if a length or offset is incorrect
*/
private void addToMessage(byte inBuf[], int inOff, int inLen)
throws IllegalStateException {
int bytesToCopy;
if (mode == Cipher.MODE_UNINITIALIZED) {
throw new IllegalStateException();
}
if (inLen == 0) {
return;
}
if (inBuf == null || inOff < 0 || inLen < 0 ||
inOff + inLen > inBuf.length) {
throw new IllegalArgumentException("input out of bounds");
}
bytesToCopy = messageToSign.length - bytesInMessage;
if (inLen < bytesToCopy) {
bytesToCopy = inLen;
}
System.arraycopy(inBuf, inOff, messageToSign, bytesInMessage,
bytesToCopy);
bytesInMessage += bytesToCopy;
}
/**
* Performs the crypto process the buffer.
*
* @param inBuf the input buffer
* @param inOff the offset in <code>input</code> where the input
* starts
* @param inLen the input length
* @param outBuf the buffer for the result
* @param outOff the offset in <code>output</code> where the result
* is stored
*
* @return the number of bytes stored in <code>output</code>
*
* @exception IllegalStateException if this cipher is in a wrong state
* (e.g., has not been initialized)
* @exception IllegalBlockSizeException if this cipher is a block cipher,
* no padding has been requested (only in encryption mode), and the total
* input length of the data processed by this cipher is not a multiple of
* block size
* @exception ShortBufferException if the given output buffer is too small
* to hold the result
* @exception BadPaddingException if this cipher is in decryption mode,
* and (un)padding has been requested, but the decrypted data is not
* bounded by the appropriate padding bytes
* @exception IllegalArgumentException if input is greater than the
* cipher with the given key can handle
*/
private int performRsa(byte inBuf[], int inOff, int inLen,
byte outBuf[], int outOff)
throws IllegalStateException, ShortBufferException,
IllegalBlockSizeException, BadPaddingException {
int modLen;
int outLen;
byte[] tmp;
byte[] res;
int padLen;
int endOfPad;
modLen = ckey.getModulusLen();
switch (mode) {
case Cipher.ENCRYPT_MODE:
if (inLen > modLen - 11) {
throw new IllegalArgumentException("Too much input");
}
/*
* Add PKCS#1 (ver 1.5) padding
* 0x00 | 0x02 | <random, non-zero pad bytes> | 0x00 | <data>
*/
tmp = new byte[modLen];
tmp[0] = (byte) 0x00;
padLen = modLen - inLen - 3;
endOfPad = padLen + PAD_OFFSET;
if (ckey instanceof RSAPublicKey) {
tmp[1] = (byte) 0x02; // for block type 02
// Use random padding (replacing 0x00s)
rnd.nextBytes(tmp, PAD_OFFSET, padLen);
for (int i = PAD_OFFSET; i < endOfPad; i++) {
if (tmp[i] == (byte) 0x00) {
// padding byte must be non-zero
tmp[i] = (byte) 0xff;
}
}
} else {
// NOTE: RFC2313 suggests 0x01 for private key signatures
tmp[1] = (byte) 0x01;
for (int i = PAD_OFFSET; i < endOfPad; i++) {
tmp[i] = (byte) 0xff;
}
}
if (inLen > modLen) {
throw new IllegalArgumentException("inlen > modlen");
}
tmp[modLen - inLen - 1] = (byte) 0x00;
System.arraycopy(inBuf, inOff, tmp, modLen - inLen, inLen);
res = doIt(tmp);
if (outOff + res.length > outBuf.length) {
throw new ShortBufferException();
}
System.arraycopy(res, 0, outBuf, outOff, res.length);
outLen = res.length;
break;
case Cipher.DECRYPT_MODE:
// This is specified in RFC2313
if (inLen != modLen) {
throw new IllegalArgumentException("inlen != modlen");
}
if (inOff != 0) {
tmp = new byte[modLen];
System.arraycopy(inBuf, inOff, tmp, 0, modLen);
res = doIt(tmp);
} else {
res = doIt(inBuf);
}
// Count number of padding bytes (these must be non-zero)
padLen = 0;
for (int i = 2; (i < res.length) && (res[i] != (byte) 0x00); i++) {
padLen++;
}
/*
* Note that whatever our decryption key type is,
* the other side used an opposite key type when encrypting
* so if our key type is TYPE_RSA_PUBLIC, the sender used
* TYPE_RSA_PRIVATE and the expected block type after
* decryption (before encryption) is 0x00 or 0x01
*/
if ((padLen < modLen - 3) && (res.length > 1) &&
(res[0] == (byte) 0x00) &&
(((ckey instanceof RSAPublicKey) &&
((res[1] == (byte) 0x01) || (res[1] == (byte) 0x00))) ||
((ckey instanceof RSAPrivateKey) &&
(res[1] == (byte) 0x02)))) {
outLen = modLen - padLen - 3;
if (outOff + outLen > outBuf.length) {
throw new ShortBufferException();
}
System.arraycopy(res, padLen + 3, outBuf, outOff, outLen);
} else {
throw new BadPaddingException();
}
break;
default:
throw new IllegalStateException();
}
return outLen;
}
/**
* Process the final data record.
*
* @param inBuf input buffer of data
* @param inOff offset in the provided input buffer
* @param inLen length of data to be processed
* @param outBuf output buffer of data
* @param outOff offset in the provided output buffer
* @return number of bytes copied to output buffer
*
* @exception IllegalStateException if this cipher is in a wrong state
* (e.g., has not been initialized)
* @exception IllegalBlockSizeException if this cipher is a block cipher,
* no padding has been requested (only in encryption mode), and the total
* input length of the data processed by this cipher is not a multiple of
* block size
* @exception ShortBufferException if the given output buffer is too small
* to hold the result
* @exception BadPaddingException if this cipher is in decryption mode,
* and (un)padding has been requested, but the decrypted data is not
* bounded by the appropriate padding bytes
* @exception IllegalArgumentException if input is greater than the
* cipher with the given key can handle, or the output
* parameters are invalid
*/
public int doFinal(byte[] inBuf, int inOff, int inLen,
byte[] outBuf, int outOff)
throws IllegalStateException, ShortBufferException,
IllegalBlockSizeException, BadPaddingException {
addToMessage(inBuf, inOff, inLen);
if (outBuf == null || outOff < 0) {
throw new IllegalArgumentException("output out of bounds");
}
int val = performRsa(messageToSign, 0, bytesInMessage, outBuf, outOff);
try {
init(mode, ckey);
} catch (InvalidKeyException ike) {
// Ignore, nothing to do
}
return val;
}
}
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