/*
 * =============================================================================
 * 
 *   Copyright (c) 2007-2010, The JASYPT team (http://www.jasypt.org)
 * 
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 * 
 *       http://www.apache.org/licenses/LICENSE-2.0
 * 
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 * 
 * =============================================================================
 */
package org.jasypt.encryption.pbe;

import java.math.BigInteger;
import java.security.Provider;

import org.jasypt.commons.CommonUtils;
import org.jasypt.encryption.pbe.config.PBEConfig;
import org.jasypt.exceptions.AlreadyInitializedException;
import org.jasypt.iv.IvGenerator;
import org.jasypt.salt.SaltGenerator;





 Pooled implementation of PBEBigIntegerEncryptor that in fact contains an array of StandardPBEBigIntegerEncryptor objects which are used to attend encrypt and decrypt requests in round-robin. This should result in higher performance in multiprocessor systems. 
 Configuration of this class is equivalent to that of StandardPBEBigIntegerEncryptor. 

This class is thread-safe.

Author:
Daniel Fernández
Since:
1.7/**
 * <p>
 * Pooled implementation of {@link PBEBigIntegerEncryptor} that in fact contains
 * an array of {@link StandardPBEBigIntegerEncryptor} objects which are used
 * to attend encrypt and decrypt requests in round-robin. This should
 * result in higher performance in multiprocessor systems.
 * </p>
 * <p>
 * Configuration of this class is equivalent to that of
 * {@link StandardPBEBigIntegerEncryptor}.
 * </p>
 * <p>
 * This class is <i>thread-safe</i>.
 * </p>
 * 
 * 
 * @since 1.7
 * 
 * @author Daniel Fern&aacute;ndez
 *
 */
public final class PooledPBEBigIntegerEncryptor implements PBEBigIntegerCleanablePasswordEncryptor {

    
    private final StandardPBEBigIntegerEncryptor firstEncryptor;
    
    private PBEConfig config = null;
    private int poolSize = 0;
    private boolean poolSizeSet = false;
    
    private StandardPBEBigIntegerEncryptor[] pool;
    private int roundRobin = 0;


    /*
     * Flag which indicates whether the digester has been initialized or not.
     * 
     * Once initialized, no further modifications to its configuration will
     * be allowed.
     */
    private boolean initialized = false;
    
    
    
    
Creates a new instance of PooledStandardPBEBigIntegerEncryptor.
/**
     * Creates a new instance of <tt>PooledStandardPBEBigIntegerEncryptor</tt>.
     */
    public PooledPBEBigIntegerEncryptor() {
        super();
        this.firstEncryptor = new StandardPBEBigIntegerEncryptor();
    }

    
    
    

Sets a PBEConfig object 
for the encryptor. If this config
object is set, it will be asked values for:


  
Algorithm
  
Security Provider (or provider name)
  
Password
  
Hashing iterations for obtaining the encryption key
  
Salt generator
  
Output type (base64, hexadecimal) 
      (only StringPBEConfig)


The non-null values it returns will override the default ones, 
and will be overriden by any values specified with a setX
method.

Params:
config – the PBEConfig object to be used as the 
              source for configuration parameters./**
     * <p>
     * Sets a <tt>{@link org.jasypt.encryption.pbe.config.PBEConfig}</tt> object 
     * for the encryptor. If this config
     * object is set, it will be asked values for:
     * </p>
     * 
     * <ul>
     *   <li>Algorithm</li>
     *   <li>Security Provider (or provider name)</li>
     *   <li>Password</li>
     *   <li>Hashing iterations for obtaining the encryption key</li>
     *   <li>Salt generator</li>
     *   <li>Output type (base64, hexadecimal) 
     *       (only <tt>StringPBEConfig</tt>)</li>
     * </ul>
     * 
     * <p>
     * The non-null values it returns will override the default ones, 
     * <i>and will be overriden by any values specified with a <tt>setX</tt>
     * method</i>.
     * </p>
     * 
     * @param config the <tt>PBEConfig</tt> object to be used as the 
     *               source for configuration parameters.
     */
    public synchronized void setConfig(final PBEConfig config) {
        this.firstEncryptor.setConfig(config);
        this.config = config;
    }

    
    

Sets the algorithm to be used for encryption, like 
PBEWithMD5AndDES.


This algorithm has to be supported by your JCE provider (if you specify
one, or the default JVM provider if you don't) and, if it is supported,
you can also specify mode and padding for 
it, like ALGORITHM/MODE/PADDING.

Params:
algorithm – the name of the algorithm to be used./**
     * <p>
     * Sets the algorithm to be used for encryption, like 
     * <tt>PBEWithMD5AndDES</tt>.
     * </p>
     * <p>
     * This algorithm has to be supported by your JCE provider (if you specify
     * one, or the default JVM provider if you don't) and, if it is supported,
     * you can also specify <i>mode</i> and <i>padding</i> for 
     * it, like <tt>ALGORITHM/MODE/PADDING</tt>.
     * </p>
     * 
     * @param algorithm the name of the algorithm to be used.
     */
    public void setAlgorithm(final String algorithm) {
        this.firstEncryptor.setAlgorithm(algorithm);
    }

    
    

Sets the password to be used.


There is no default value for password, so not setting this parameter either from a PBEConfig object or from a call to setPassword will result in an
EncryptionInitializationException being thrown during initialization.

Params:
password – the password to be used./**
     * <p>
     * Sets the password to be used.
     * </p>
     * <p>
     * <b>There is no default value for password</b>, so not setting
     * this parameter either from a 
     * {@link org.jasypt.encryption.pbe.config.PBEConfig} object or from
     * a call to <tt>setPassword</tt> will result in an
     * EncryptionInitializationException being thrown during initialization.
     * </p>
     * 
     * @param password the password to be used.
     */
    public void setPassword(final String password) {
        this.firstEncryptor.setPassword(password);
    }
    
    
    

Sets the password to be used, as a char[].


This allows the password to be specified as a cleanable
char[] instead of a String, in extreme security conscious environments
in which no copy of the password as an immutable String should
be kept in memory.


Important: the array specified as a parameter WILL BE COPIED
in order to be stored as encryptor configuration. The caller of
this method will therefore be responsible for its cleaning (jasypt
will only clean the internally stored copy).


There is no default value for password, so not setting this parameter either from a PBEConfig object or from a call to setPassword will result in an
EncryptionInitializationException being thrown during initialization.

Params:
password – the password to be used.
Since:
1.8/**
     * <p>
     * Sets the password to be used, as a char[].
     * </p>
     * <p>
     * This allows the password to be specified as a <i>cleanable</i>
     * char[] instead of a String, in extreme security conscious environments
     * in which no copy of the password as an immutable String should
     * be kept in memory.
     * </p>
     * <p>
     * <b>Important</b>: the array specified as a parameter WILL BE COPIED
     * in order to be stored as encryptor configuration. The caller of
     * this method will therefore be responsible for its cleaning (jasypt
     * will only clean the internally stored copy).
     * </p>
     * <p>
     * <b>There is no default value for password</b>, so not setting
     * this parameter either from a 
     * {@link org.jasypt.encryption.pbe.config.PBEConfig} object or from
     * a call to <tt>setPassword</tt> will result in an
     * EncryptionInitializationException being thrown during initialization.
     * </p>
     * 
     * @since 1.8
     * 
     * @param password the password to be used.
     */
    public synchronized void setPasswordCharArray(char[] password) {
        this.firstEncryptor.setPasswordCharArray(password);
    }
    

    

Set the number of hashing iterations applied to obtain the
encryption key.


This mechanism is explained in 
PKCS #5: Password-Based Cryptography Standard.

Params:
keyObtentionIterations – the number of iterations/**
     * <p>
     * Set the number of hashing iterations applied to obtain the
     * encryption key.
     * </p>
     * <p>
     * This mechanism is explained in 
     * <a href="http://www.rsasecurity.com/rsalabs/node.asp?id=2127" 
     * target="_blank">PKCS &#035;5: Password-Based Cryptography Standard</a>.
     * </p>
     * 
     * @param keyObtentionIterations the number of iterations
     */
    public void setKeyObtentionIterations(final int keyObtentionIterations) {
        this.firstEncryptor.setKeyObtentionIterations(keyObtentionIterations);
    }

    
    
 Sets the salt generator to be used. If no salt generator is specified, an instance of RandomSaltGenerator will be used. 
Params:
saltGenerator – the salt generator to be used./**
     * <p>
     * Sets the salt generator to be used. If no salt generator is specified,
     * an instance of {@link org.jasypt.salt.RandomSaltGenerator} will be used. 
     * </p>
     * 
     * @param saltGenerator the salt generator to be used.
     */
    public void setSaltGenerator(final SaltGenerator saltGenerator) {
        this.firstEncryptor.setSaltGenerator(saltGenerator);
    }

    
 Sets the IV generator to be used. If no IV generator is specified, an instance of NoIvGenerator will be used. 
Params:
ivGenerator – the IV generator to be used./**
     * <p>
     * Sets the IV generator to be used. If no IV generator is specified,
     * an instance of {@link org.jasypt.iv.NoIvGenerator} will be used.
     * </p>
     *
     * @param ivGenerator the IV generator to be used.
     */
    public void setIvGenerator(final IvGenerator ivGenerator) {
        this.firstEncryptor.setIvGenerator(ivGenerator);
    }
    
    
    

Sets the name of the security provider to be asked for the
encryption algorithm. This security provider has to be registered 
beforehand at the JVM security framework. 

 The provider can also be set with the setProvider(Provider) method, in which case it will not be necessary neither registering the provider beforehand, nor calling this setProviderName(String) method to specify a provider name. 
 Note that a call to setProvider(Provider) overrides any value set by this method. 

If no provider name / provider is explicitly set, the default JVM
provider will be used.

Params:
providerName – the name of the security provider to be asked
                    for the encryption algorithm./**
     * <p>
     * Sets the name of the security provider to be asked for the
     * encryption algorithm. This security provider has to be registered 
     * beforehand at the JVM security framework. 
     * </p>
     * <p>
     * The provider can also be set with the {@link #setProvider(Provider)}
     * method, in which case it will not be necessary neither registering
     * the provider beforehand,
     * nor calling this {@link #setProviderName(String)} method to specify
     * a provider name.
     * </p>
     * <p>
     * Note that a call to {@link #setProvider(Provider)} overrides any value 
     * set by this method.
     * </p>
     * <p>
     * If no provider name / provider is explicitly set, the default JVM
     * provider will be used.
     * </p>
     * 
     * @param providerName the name of the security provider to be asked
     *                     for the encryption algorithm.
     */
    public void setProviderName(final String providerName) {
        this.firstEncryptor.setProviderName(providerName);
    }
    
    
    

Sets the security provider to be asked for the encryption algorithm.
The provider does not have to be registered at the security 
infrastructure beforehand, and its being used here will not result in
its being registered.

 If this method is called, calling setProviderName(String) becomes unnecessary. 

If no provider name / provider is explicitly set, the default JVM
provider will be used.

Params:
provider – the provider to be asked for the chosen algorithm/**
     * <p>
     * Sets the security provider to be asked for the encryption algorithm.
     * The provider does not have to be registered at the security 
     * infrastructure beforehand, and its being used here will not result in
     * its being registered.
     * </p>
     * <p>
     * If this method is called, calling {@link #setProviderName(String)}
     * becomes unnecessary.
     * </p>
     * <p>
     * If no provider name / provider is explicitly set, the default JVM
     * provider will be used.
     * </p>
     * 
     * @param provider the provider to be asked for the chosen algorithm
     */
    public void setProvider(final Provider provider) {
        this.firstEncryptor.setProvider(provider);
    }

    
    
    

Sets the size of the pool of digesters to be created.


This parameter is required.

Params:
poolSize – size of the pool/**
     * <p>
     * Sets the size of the pool of digesters to be created.
     * </p>
     * <p>
     * This parameter is <b>required</b>.
     * </p>
     * 
     * @param poolSize size of the pool
     */
    public synchronized void setPoolSize(final int poolSize) {
        CommonUtils.validateIsTrue(poolSize > 0, "Pool size be > 0");
        if (isInitialized()) {
            throw new AlreadyInitializedException();
        }
        this.poolSize = poolSize;
        this.poolSizeSet = true;
    }

    
    
    
    

  Returns true if the encryptor has already been initialized, false if
  not.
 
  Initialization happens:


  
When initialize is called.
  
When encrypt or decrypt are called for the
      first time, if initialize has not been called before.


  Once an encryptor has been initialized, trying to
  change its configuration will
  result in an AlreadyInitializedException being thrown.

Returns:
true if the encryptor has already been initialized, false if
        not./**
     * <p>
     *   Returns true if the encryptor has already been initialized, false if
     *   not.<br/> 
     *   Initialization happens:
     * </p>
     * <ul>
     *   <li>When <tt>initialize</tt> is called.</li>
     *   <li>When <tt>encrypt</tt> or <tt>decrypt</tt> are called for the
     *       first time, if <tt>initialize</tt> has not been called before.</li>
     * </ul>
     * <p>
     *   Once an encryptor has been initialized, trying to
     *   change its configuration will
     *   result in an <tt>AlreadyInitializedException</tt> being thrown.
     * </p>
     * 
     * @return true if the encryptor has already been initialized, false if
     *         not.
     */
    public boolean isInitialized() {
        return this.initialized;
    }

    
    

Initialize the encryptor.


This operation will consist in determining the actual configuration 
values to be used, and then initializing the encryptor with them.


These values are decided by applying the following priorities:


  
First, the default values are considered (except for password).
  
  
Then, if a 
      PBEConfig 
      object has been set with
      setConfig, the non-null values returned by its
      getX methods override the default values.
  
Finally, if the corresponding setX method has been called
      on the encryptor itself for any of the configuration parameters, 
      the values set by these calls override all of the above.


  Once an encryptor has been initialized, trying to
  change its configuration will
  result in an AlreadyInitializedException being thrown.

Throws:
EncryptionInitializationException – if initialization could not
        be correctly done (for example, no password has been set)./**
     * <p>
     * Initialize the encryptor.
     * </p>
     * <p>
     * This operation will consist in determining the actual configuration 
     * values to be used, and then initializing the encryptor with them.
     * <br/>
     * These values are decided by applying the following priorities:
     * </p>
     * <ol>
     *   <li>First, the default values are considered (except for password).
     *   </li>
     *   <li>Then, if a 
     *       <tt>{@link org.jasypt.encryption.pbe.config.PBEConfig}</tt> 
     *       object has been set with
     *       <tt>setConfig</tt>, the non-null values returned by its
     *       <tt>getX</tt> methods override the default values.</li>
     *   <li>Finally, if the corresponding <tt>setX</tt> method has been called
     *       on the encryptor itself for any of the configuration parameters, 
     *       the values set by these calls override all of the above.</li>
     * </ol>
     * <p>
     *   Once an encryptor has been initialized, trying to
     *   change its configuration will
     *   result in an <tt>AlreadyInitializedException</tt> being thrown.
     * </p>
     * 
     * @throws EncryptionInitializationException if initialization could not
     *         be correctly done (for example, no password has been set).
     */
    public synchronized void initialize() {
        
        // Double-check to avoid synchronization issues
        if (!this.initialized) {

            if (this.config != null) {
                
                final Integer configPoolSize = this.config.getPoolSize();

                this.poolSize = 
                    ((this.poolSizeSet) || (configPoolSize == null))?
                            this.poolSize : configPoolSize.intValue();
                
            }
            
            if (this.poolSize <= 0) {
                throw new IllegalArgumentException("Pool size must be set and > 0");
            }
            
            this.pool = this.firstEncryptor.cloneAndInitializeEncryptor(this.poolSize);
            
            this.initialized = true;
            
        }
        
    }


    


    
    

Encrypts a message using the specified configuration.


Important: The size of the result of encrypting a number, depending
on the algorithm, may be much bigger (in bytes) than the size of the 
encrypted number itself. For example, encrypting a 4-byte integer can
result in an encrypted 16-byte number. This can lead the user into 
problems if the encrypted values are to be stored and not enough room 
has been provided.


The mechanisms applied to perform the encryption operation are described
in PKCS #5: Password-Based Cryptography Standard.


This encryptor uses a salt for each encryption
operation. The size of the salt depends on the algorithm
being used. This salt is used
for creating the encryption key and, if generated by a random generator,
it is also appended unencrypted at the beginning
of the results so that a decryption operation can be performed.


If a random salt generator is used, two encryption results for 
the same message will always be different
(except in the case of random salt coincidence). This may enforce
security by difficulting brute force attacks on sets of data at a time
and forcing attackers to perform a brute force attack on each separate
piece of encrypted data.

Params:
message – the BigInteger message to be encrypted
Throws:
EncryptionOperationNotPossibleException – if the encryption 
        operation fails, ommitting any further information about the
        cause for security reasons.
EncryptionInitializationException – if initialization could not
        be correctly done (for example, no password has been set).
Returns:
the result of encryption/**
     * <p>
     * Encrypts a message using the specified configuration.
     * </p>
     * <p>
     * <b>Important</b>: The size of the result of encrypting a number, depending
     * on the algorithm, may be much bigger (in bytes) than the size of the 
     * encrypted number itself. For example, encrypting a 4-byte integer can
     * result in an encrypted 16-byte number. This can lead the user into 
     * problems if the encrypted values are to be stored and not enough room 
     * has been provided.
     * </p>
     * <p>
     * The mechanisms applied to perform the encryption operation are described
     * in <a href="http://www.rsasecurity.com/rsalabs/node.asp?id=2127" 
     * target="_blank">PKCS &#035;5: Password-Based Cryptography Standard</a>.
     * </p>
     * <p>
     * This encryptor uses a salt for each encryption
     * operation. The size of the salt depends on the algorithm
     * being used. This salt is used
     * for creating the encryption key and, if generated by a random generator,
     * it is also appended unencrypted at the beginning
     * of the results so that a decryption operation can be performed.
     * </p>
     * <p>
     * <b>If a random salt generator is used, two encryption results for 
     * the same message will always be different
     * (except in the case of random salt coincidence)</b>. This may enforce
     * security by difficulting brute force attacks on sets of data at a time
     * and forcing attackers to perform a brute force attack on each separate
     * piece of encrypted data.
     * </p>
     * 
     * @param message the BigInteger message to be encrypted
     * @return the result of encryption 
     * @throws EncryptionOperationNotPossibleException if the encryption 
     *         operation fails, ommitting any further information about the
     *         cause for security reasons.
     * @throws EncryptionInitializationException if initialization could not
     *         be correctly done (for example, no password has been set).
     */
    public BigInteger encrypt(final BigInteger message) {

        // Check initialization
        if (!isInitialized()) {
            initialize();
        }
        
        int poolPosition;
        synchronized(this) {
            poolPosition = this.roundRobin;
            this.roundRobin = (this.roundRobin + 1) % this.poolSize;
        }
        
        return this.pool[poolPosition].encrypt(message);
        
    }

    
    

Decrypts a message using the specified configuration.


The mechanisms applied to perform the decryption operation are described
in PKCS #5: Password-Based Cryptography Standard.


If a random salt generator is used, this decryption operation will
expect to find an unencrypted salt at the 
beginning of the encrypted input, so that the decryption operation can be
correctly performed (there is no other way of knowing it).

Params:
encryptedMessage – the BigInteger message to be decrypted
Throws:
EncryptionOperationNotPossibleException – if the decryption 
        operation fails, ommitting any further information about the
        cause for security reasons.
EncryptionInitializationException – if initialization could not
        be correctly done (for example, no password has been set).
Returns:
the result of decryption/**
     * <p>
     * Decrypts a message using the specified configuration.
     * </p>
     * <p>
     * The mechanisms applied to perform the decryption operation are described
     * in <a href="http://www.rsasecurity.com/rsalabs/node.asp?id=2127" 
     * target="_blank">PKCS &#035;5: Password-Based Cryptography Standard</a>.
     * </p>
     * <p>
     * If a random salt generator is used, this decryption operation will
     * expect to find an unencrypted salt at the 
     * beginning of the encrypted input, so that the decryption operation can be
     * correctly performed (there is no other way of knowing it).
     * </p>
     * 
     * @param encryptedMessage the BigInteger message to be decrypted
     * @return the result of decryption 
     * @throws EncryptionOperationNotPossibleException if the decryption 
     *         operation fails, ommitting any further information about the
     *         cause for security reasons.
     * @throws EncryptionInitializationException if initialization could not
     *         be correctly done (for example, no password has been set).
     */
    public BigInteger decrypt(final BigInteger encryptedMessage) {

        // Check initialization
        if (!isInitialized()) {
            initialize();
        }
        
        int poolPosition;
        synchronized(this) {
            poolPosition = this.roundRobin;
            this.roundRobin = (this.roundRobin + 1) % this.poolSize;
        }
        
        return this.pool[poolPosition].decrypt(encryptedMessage);
        
    }

    
    
    
}