Java tutorial
/** * Copyright 2005-2011 hdiv.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.hdiv.cipher; import java.security.NoSuchAlgorithmException; import java.security.NoSuchProviderException; import javax.crypto.Cipher; import javax.crypto.NoSuchPaddingException; import javax.crypto.spec.IvParameterSpec; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.hdiv.exception.HDIVException; import org.hdiv.util.HDIVUtil; /** * The principal class related with cryptography. It has the responsibility to encrypt and decrypt data. * * @author Roberto Velasco * @see javax.crypto.Cipher * @see javax.crypto.spec.IvParameterSpec */ public class CipherHTTP implements ICipherHTTP { /** * Universal version identifier. Deserialization uses this number to ensure that a loaded class corresponds exactly * to a serialized object. */ private static final long serialVersionUID = -1731737465730669951L; /** * Commons Logging instance. */ private Log log = LogFactory.getLog(CipherHTTP.class); /** * Name of the default cipher algorithm */ private static final String DEFAULT_ALGORITHM = "AES/CBC/PKCS5Padding"; /** * Algorithm name of cipher object */ private String transformation = DEFAULT_ALGORITHM; /** * Provider name */ private String provider; /** * This object provides the functionality of a cryptographic cipher for encryption and decryption */ private Cipher cipher; private IvParameterSpec ivSpec; private boolean encryptMode; /** * Generates a Cipher object that implements the specified transformation. */ public void init() { try { if (this.provider == null) { this.cipher = Cipher.getInstance(this.transformation); } else { this.cipher = Cipher.getInstance(this.transformation, this.provider); } if (log.isDebugEnabled()) { log.debug("New CipherHTTP instance [cipher = " + this.cipher + "]"); } } catch (NoSuchProviderException e) { throw new HDIVException(e.getMessage()); } catch (NoSuchAlgorithmException e) { throw new HDIVException(e.getMessage()); } catch (NoSuchPaddingException e) { throw new HDIVException(e.getMessage()); } } /** * <p> * Generates a Cipher object that implements the specified <code>transformation</code>, initializes cipher vector * and initializes cipher to encryption mode with a key and a set of algorithm parameters. * </p> * <p> * The name of the transformation, e.g., DES/CBC/PKCS5Padding. See Appendix A in the <a * href="../../../guide/security/jce/JCERefGuide.html#AppA"> Java Cryptography Extension Reference Guide for * information about standard transformation names. * </p> * * @param key * the encryption key * @throws HDIVException * if there is an initialization error. */ public void initEncryptMode(Key key) { try { // vector initialization this.ivSpec = new IvParameterSpec(key.getInitVector()); // Constant used to initialize cipher to encryption mode this.cipher.init(Cipher.ENCRYPT_MODE, key.getKey(), this.ivSpec); this.encryptMode = true; } catch (Exception e) { String errorMessage = HDIVUtil.getMessage("cipher.init.encrypt", e.getMessage()); throw new HDIVException(errorMessage, e); } } /** * Generates a Cipher object that implements the specified <code>transformation</code>, initializes cipher vector * and initializes cipher to decryption mode with a key and a set of algorithm parameters. * * @param key * the encryption key * @throws HDIVException * if there is an initialization error. */ public void initDecryptMode(Key key) { try { // vector initialization this.ivSpec = new IvParameterSpec(key.getInitVector()); this.cipher.init(Cipher.DECRYPT_MODE, key.getKey(), this.ivSpec); this.encryptMode = false; } catch (Exception e) { String errorMessage = HDIVUtil.getMessage("cipher.init.decrypt", e.getMessage()); throw new HDIVException(errorMessage, e); } } /** * Encrypts <code>data</code> in a single-part operation, or finishes a multiple-part operation. The data is * encrypted depending on how this cipher was initialized. * <p> * The bytes in the input buffer, and any input bytes that may have been buffered during a previous update * operation, are processed, with padding (if requested) being applied. The result is stored in a new buffer. * </p> * <p> * if any exception is thrown, this cipher object may need to be reset before it can be used again. * </p> * * @param data * The input buffer to encrypt * @return The new buffer with the result * @throws HDIVException * if any exception is thrown in encryption process. */ public byte[] encrypt(byte[] data) { try { return cipher.doFinal(data); } catch (Exception e) { String errorMessage = HDIVUtil.getMessage("cipher.encrypt", e.getMessage()); throw new HDIVException(errorMessage, e); } } /** * Decrypts <code>data</code> in a single-part operation, or finishes a multiple-part operation. The data is * decrypted depending on how this cipher was initialized. * <p> * The bytes in the input buffer, and any input bytes that may have been buffered during a previous update * operation, are processed, with padding (if requested) being applied. The result is stored in a new buffer. * </p> * <p> * if any exception is thrown, this cipher object may need to be reset before it can be used again. * </p> * * @param data * The input buffer to decrypt * @return The new buffer with the result * @throws HDIVException * if any exception is thrown in decryption process. */ public byte[] decrypt(byte[] data) { try { return cipher.doFinal(data); } catch (Exception e) { String errorMessage = HDIVUtil.getMessage("cipher.decrypt", e.getMessage()); throw new HDIVException(errorMessage, e); } } /** * @param transformation * The transformation to set for the cipher factory bean. */ public void setTransformation(String transformation) { this.transformation = transformation; } /** * @param provider * The provider to set. */ public void setProvider(String provider) { this.provider = provider; } public boolean isEncryptMode() { return encryptMode; } public void setEncryptMode(boolean encryptMode) { this.encryptMode = encryptMode; } }