/*
* Copyright (c) 2005, 2007, Oracle and/or its affiliates. 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package com.sun.crypto.provider;
import java.io.*;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.util.Arrays;
import java.security.KeyRep;
import java.security.GeneralSecurityException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
/**
* This class represents a PBE key derived using PBKDF2 defined
* in PKCS#5 v2.0. meaning that
* 1) the password must consist of characters which will be converted
* to bytes using UTF-8 character encoding.
* 2) salt, iteration count, and to be derived key length are supplied
*
* @author Valerie Peng
*
*/
final class PBKDF2KeyImpl implements javax.crypto.interfaces.PBEKey {
static final long serialVersionUID = -2234868909660948157L;
private char[] passwd;
private byte[] salt;
private int iterCount;
private byte[] key;
private Mac prf;
private static byte[] getPasswordBytes(char[] passwd) {
Charset utf8 = Charset.forName("UTF-8");
CharBuffer cb = CharBuffer.wrap(passwd);
ByteBuffer bb = utf8.encode(cb);
int len = bb.limit();
byte[] passwdBytes = new byte[len];
bb.get(passwdBytes, 0, len);
return passwdBytes;
}
/**
* Creates a PBE key from a given PBE key specification.
*
* @param key the given PBE key specification
*/
PBKDF2KeyImpl(PBEKeySpec keySpec, String prfAlgo)
throws InvalidKeySpecException {
char[] passwd = keySpec.getPassword();
if (passwd == null) {
// Should allow an empty password.
this.passwd = new char[0];
} else {
this.passwd = passwd.clone();
}
// Convert the password from char[] to byte[]
byte[] passwdBytes = getPasswordBytes(this.passwd);
this.salt = keySpec.getSalt();
if (salt == null) {
throw new InvalidKeySpecException("Salt not found");
}
this.iterCount = keySpec.getIterationCount();
if (iterCount == 0) {
throw new InvalidKeySpecException("Iteration count not found");
} else if (iterCount < 0) {
throw new InvalidKeySpecException("Iteration count is negative");
}
int keyLength = keySpec.getKeyLength();
if (keyLength == 0) {
throw new InvalidKeySpecException("Key length not found");
} else if (keyLength == 0) {
throw new InvalidKeySpecException("Key length is negative");
}
try {
this.prf = Mac.getInstance(prfAlgo, "SunJCE");
} catch (NoSuchAlgorithmException nsae) {
// not gonna happen; re-throw just in case
InvalidKeySpecException ike = new InvalidKeySpecException();
ike.initCause(nsae);
throw ike;
} catch (NoSuchProviderException nspe) {
// Again, not gonna happen; re-throw just in case
InvalidKeySpecException ike = new InvalidKeySpecException();
ike.initCause(nspe);
throw ike;
}
this.key = deriveKey(prf, passwdBytes, salt, iterCount, keyLength);
}
private static byte[] deriveKey(Mac prf, byte[] password, byte[] salt,
int iterCount, int keyLengthInBit) {
int keyLength = keyLengthInBit/8;
byte[] key = new byte[keyLength];
try {
int hlen = prf.getMacLength();
int intL = (keyLength + hlen - 1)/hlen; // ceiling
int intR = keyLength - (intL - 1)*hlen; // residue
byte[] ui = new byte[hlen];
byte[] ti = new byte[hlen];
SecretKey macKey = new SecretKeySpec(password, prf.getAlgorithm());
prf.init(macKey);
byte[] ibytes = new byte[4];
for (int i = 1; i <= intL; i++) {
prf.update(salt);
ibytes[3] = (byte) i;
ibytes[2] = (byte) ((i >> 8) & 0xff);
ibytes[1] = (byte) ((i >> 16) & 0xff);
ibytes[0] = (byte) ((i >> 24) & 0xff);
prf.update(ibytes);
prf.doFinal(ui, 0);
System.arraycopy(ui, 0, ti, 0, ui.length);
for (int j = 2; j <= iterCount; j++) {
prf.update(ui);
prf.doFinal(ui, 0);
// XOR the intermediate Ui's together.
for (int k = 0; k < ui.length; k++) {
ti[k] ^= ui[k];
}
}
if (i == intL) {
System.arraycopy(ti, 0, key, (i-1)*hlen, intR);
} else {
System.arraycopy(ti, 0, key, (i-1)*hlen, hlen);
}
}
} catch (GeneralSecurityException gse) {
throw new RuntimeException("Error deriving PBKDF2 keys");
}
return key;
}
public byte[] getEncoded() {
return (byte[]) key.clone();
}
public String getAlgorithm() {
return "PBKDF2With" + prf.getAlgorithm();
}
public int getIterationCount() {
return iterCount;
}
public char[] getPassword() {
return (char[]) passwd.clone();
}
public byte[] getSalt() {
return salt.clone();
}
public String getFormat() {
return "RAW";
}
/**
* Calculates a hash code value for the object.
* Objects that are equal will also have the same hashcode.
*/
public int hashCode() {
int retval = 0;
for (int i = 1; i < this.key.length; i++) {
retval += this.key[i] * i;
}
return(retval ^= getAlgorithm().toLowerCase().hashCode());
}
public boolean equals(Object obj) {
if (obj == this)
return true;
if (!(obj instanceof SecretKey))
return false;
SecretKey that = (SecretKey) obj;
if (!(that.getAlgorithm().equalsIgnoreCase(getAlgorithm())))
return false;
if (!(that.getFormat().equalsIgnoreCase("RAW")))
return false;
byte[] thatEncoded = that.getEncoded();
boolean ret = Arrays.equals(key, that.getEncoded());
java.util.Arrays.fill(thatEncoded, (byte)0x00);
return ret;
}
/**
* Replace the PBE key to be serialized.
*
* @return the standard KeyRep object to be serialized
*
* @throws ObjectStreamException if a new object representing
* this PBE key could not be created
*/
private Object writeReplace() throws java.io.ObjectStreamException {
return new KeyRep(KeyRep.Type.SECRET, getAlgorithm(),
getFormat(), getEncoded());
}
/**
* Ensures that the password bytes of this key are
* erased when there are no more references to it.
*/
protected void finalize() throws Throwable {
try {
if (this.passwd != null) {
java.util.Arrays.fill(this.passwd, (char) '0');
this.passwd = null;
}
if (this.key != null) {
java.util.Arrays.fill(this.key, (byte)0x00);
this.key = null;
}
} finally {
super.finalize();
}
}
}