diff options
Diffstat (limited to 'libjava/classpath/gnu/javax/crypto/RSACipherImpl.java')
| -rw-r--r-- | libjava/classpath/gnu/javax/crypto/RSACipherImpl.java | 311 |
1 files changed, 311 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/javax/crypto/RSACipherImpl.java b/libjava/classpath/gnu/javax/crypto/RSACipherImpl.java new file mode 100644 index 00000000000..0a4c29db6f1 --- /dev/null +++ b/libjava/classpath/gnu/javax/crypto/RSACipherImpl.java @@ -0,0 +1,311 @@ +/* DiffieHellmanImpl.java -- implementation of the Diffie-Hellman key agreement. + Copyright (C) 2005 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package gnu.javax.crypto; + +import gnu.classpath.ByteArray; +import gnu.classpath.debug.Component; +import gnu.classpath.debug.SystemLogger; + +import java.math.BigInteger; + +import java.security.AlgorithmParameters; +import java.security.InvalidAlgorithmParameterException; +import java.security.InvalidKeyException; +import java.security.Key; +import java.security.NoSuchAlgorithmException; +import java.security.SecureRandom; + +import java.security.interfaces.RSAKey; +import java.security.interfaces.RSAPrivateKey; +import java.security.interfaces.RSAPrivateCrtKey; +import java.security.interfaces.RSAPublicKey; + +import java.security.spec.AlgorithmParameterSpec; + +import java.util.logging.Logger; + +import javax.crypto.BadPaddingException; +import javax.crypto.Cipher; +import javax.crypto.CipherSpi; +import javax.crypto.IllegalBlockSizeException; +import javax.crypto.NoSuchPaddingException; +import javax.crypto.ShortBufferException; + +public class RSACipherImpl extends CipherSpi +{ + private static final Logger logger = SystemLogger.SYSTEM; + + private static final byte[] EMPTY = new byte[0]; + private int opmode = -1; + private RSAPrivateKey decipherKey = null; + private RSAPublicKey blindingKey = null; + private RSAPublicKey encipherKey = null; + private SecureRandom random = null; + private byte[] dataBuffer = null; + private int pos = 0; + + protected void engineSetMode (String mode) throws NoSuchAlgorithmException + { + throw new NoSuchAlgorithmException ("only one mode available"); + } + + protected void engineSetPadding (String pad) throws NoSuchPaddingException + { + throw new NoSuchPaddingException ("only one padding available"); + } + + protected int engineGetBlockSize () + { + return 1; + } + + protected int engineGetOutputSize (int inputLen) + { + int outputLen = 0; + if (decipherKey != null) + { + outputLen = (decipherKey.getModulus ().bitLength () + 7) / 8; + } + else if (encipherKey != null) + { + outputLen = (encipherKey.getModulus ().bitLength () + 7) / 8; + } + else + throw new IllegalStateException ("not initialized"); + if (inputLen > outputLen) + throw new IllegalArgumentException ("not configured to encode " + inputLen + + "bytes; at most " + outputLen); + return outputLen; + } + + protected int engineGetKeySize (final Key key) throws InvalidKeyException + { + if (!(key instanceof RSAKey)) + throw new InvalidKeyException ("not an RSA key"); + return ((RSAKey) key).getModulus ().bitLength (); + } + + protected byte[] engineGetIV () + { + return null; + } + + protected AlgorithmParameters engineGetParameters() + { + return null; + } + + protected void engineInit (int opmode, Key key, SecureRandom random) + throws InvalidKeyException + { + int outputLen = 0; + if (opmode == Cipher.ENCRYPT_MODE) + { + if (!(key instanceof RSAPublicKey)) + throw new InvalidKeyException ("expecting a RSAPublicKey"); + encipherKey = (RSAPublicKey) key; + decipherKey = null; + blindingKey = null; + outputLen = (encipherKey.getModulus ().bitLength () + 7) / 8; + } + else if (opmode == Cipher.DECRYPT_MODE) + { + if (key instanceof RSAPrivateKey) + { + decipherKey = (RSAPrivateKey) key; + encipherKey = null; + blindingKey = null; + outputLen = (decipherKey.getModulus ().bitLength () + 7) / 8; + } + else if (key instanceof RSAPublicKey) + { + if (decipherKey == null) + throw new IllegalStateException ("must configure decryption key first"); + if (!decipherKey.getModulus ().equals (((RSAPublicKey) key).getModulus ())) + throw new InvalidKeyException ("blinding key is not compatible"); + blindingKey = (RSAPublicKey) key; + return; + } + else + throw new InvalidKeyException ("expecting either an RSAPrivateKey or an RSAPublicKey (for blinding)"); + } + else + throw new IllegalArgumentException ("only encryption and decryption supported"); + this.random = random; + this.opmode = opmode; + pos = 0; + dataBuffer = new byte[outputLen]; + } + + protected void engineInit (int opmode, Key key, AlgorithmParameterSpec spec, SecureRandom random) + throws InvalidKeyException + { + engineInit (opmode, key, random); + } + + protected void engineInit (int opmode, Key key, AlgorithmParameters params, SecureRandom random) + throws InvalidKeyException + { + engineInit (opmode, key, random); + } + + protected byte[] engineUpdate (byte[] in, int offset, int length) + { + if (opmode != Cipher.ENCRYPT_MODE && opmode != Cipher.DECRYPT_MODE) + throw new IllegalStateException ("not initialized"); + System.arraycopy (in, offset, dataBuffer, pos, length); + pos += length; + return EMPTY; + } + + protected int engineUpdate (byte[] in, int offset, int length, byte[] out, int outOffset) + { + engineUpdate (in, offset, length); + return 0; + } + + protected byte[] engineDoFinal (byte[] in, int offset, int length) + throws IllegalBlockSizeException, BadPaddingException + { + engineUpdate (in, offset, length); + if (opmode == Cipher.DECRYPT_MODE) + { + if (pos < dataBuffer.length) + throw new IllegalBlockSizeException ("expecting exactly " + dataBuffer.length + " bytes"); + BigInteger enc = new BigInteger (1, dataBuffer); + byte[] dec = rsaDecrypt (enc); + logger.log (Component.CRYPTO, "RSA: decryption produced\n{0}", + new ByteArray (dec)); + if (dec[0] != 0x02) + throw new BadPaddingException ("expected padding type 2"); + int i; + for (i = 1; i < dec.length && dec[i] != 0x00; i++); + int len = dec.length - i; + byte[] result = new byte[len]; + System.arraycopy (dec, i, result, 0, len); + pos = 0; + return result; + } + else + { + offset = dataBuffer.length - pos; + if (offset < 3) + throw new IllegalBlockSizeException ("input is too large to encrypt"); + byte[] dec = new byte[dataBuffer.length]; + dec[0] = 0x02; + if (random == null) + random = new SecureRandom (); + byte[] pad = new byte[offset - 2]; + random.nextBytes (pad); + for (int i = 0; i < pad.length; i++) + if (pad[i] == 0) + pad[i] = 1; + System.arraycopy (pad, 0, dec, 1, pad.length); + dec[dec.length - pos] = 0x00; + System.arraycopy (dataBuffer, 0, dec, offset, pos); + logger.log (Component.CRYPTO, "RSA: produced padded plaintext\n{0}", + new ByteArray (dec)); + BigInteger x = new BigInteger (1, dec); + BigInteger y = x.modPow (encipherKey.getPublicExponent (), + encipherKey.getModulus ()); + byte[] enc = y.toByteArray (); + if (enc[0] == 0x00) + { + byte[] tmp = new byte[enc.length - 1]; + System.arraycopy (enc, 1, tmp, 0, tmp.length); + enc = tmp; + } + pos = 0; + return enc; + } + } + + protected int engineDoFinal (byte[] out, int offset) + throws ShortBufferException, IllegalBlockSizeException, BadPaddingException + { + byte[] result = engineDoFinal (EMPTY, 0, 0); + if (out.length - offset < result.length) + throw new ShortBufferException ("need " + result.length + ", have " + + (out.length - offset)); + System.arraycopy (result, 0, out, offset, result.length); + return result.length; + } + + protected int engineDoFinal (final byte[] input, final int offset, final int length, + final byte[] output, final int outputOffset) + throws ShortBufferException, IllegalBlockSizeException, BadPaddingException + { + byte[] result = engineDoFinal (input, offset, length); + if (output.length - outputOffset < result.length) + throw new ShortBufferException ("need " + result.length + ", have " + + (output.length - outputOffset)); + System.arraycopy (result, 0, output, outputOffset, result.length); + return result.length; + } + + /** + * Decrypts the ciphertext, employing RSA blinding if possible. + */ + private byte[] rsaDecrypt (BigInteger enc) + { + if (random == null) + random = new SecureRandom (); + BigInteger n = decipherKey.getModulus (); + BigInteger r = null; + BigInteger pubExp = null; + if (blindingKey != null) + pubExp = blindingKey.getPublicExponent (); + if (pubExp != null && (decipherKey instanceof RSAPrivateCrtKey)) + pubExp = ((RSAPrivateCrtKey) decipherKey).getPublicExponent (); + if (pubExp != null) + { + r = new BigInteger (n.bitLength () - 1, random); + enc = r.modPow (pubExp, n).multiply (enc).mod (n); + } + + BigInteger dec = enc.modPow (decipherKey.getPrivateExponent (), n); + + if (pubExp != null) + { + dec = dec.multiply (r.modInverse (n)).mod (n); + } + + return dec.toByteArray (); + } +} |