import java.security.Key; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey; import javax.crypto.SecretKeyFactory; import javax.crypto.spec.DESKeySpec; import javax.crypto.spec.IvParameterSpec; /** * DES 算法 1972美国IBM研制，对称加密算法 * @author stone * @date 2014-03-10 04:47:05 */ public class DES { // 算法名称 public static final String KEY_ALGORITHM = "DES"; // 算法名称/加密模式/填充方式 public static final String CIPHER_ALGORITHM_ECB = "DES/ECB/PKCS5Padding"; public static final String CIPHER_ALGORITHM_CBC = "DES/CBC/PKCS5Padding"; public static void main(String[] args) throws Exception { /* * 使用 ECB mode * 密钥生成器 生成密钥 * ECB mode cannot use IV */ byte[] key = generateKey(); byte[] encrypt = encrypt("胃炎F#*（x）".getBytes(), key); System.out.println(new String(decrypt(encrypt, key))); /* * 使用CBC mode * 使用密钥工厂生成密钥，加密 解密 * iv: DES in CBC mode and RSA ciphers with OAEP encoding operation. */ DESKeySpec dks = new DESKeySpec(key); SecretKeyFactory factory = SecretKeyFactory.getInstance(KEY_ALGORITHM); SecretKey secretKey = factory.generateSecret(dks); Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM_CBC); cipher.init(Cipher.ENCRYPT_MODE, secretKey, new IvParameterSpec(getIV())); byte[] enc = cipher.doFinal("胃炎A%F#*（x）".getBytes()); //加密 cipher.init(Cipher.DECRYPT_MODE, secretKey, new IvParameterSpec(getIV())); byte[] dec = cipher.doFinal(enc); // 解密 System.out.println(new String(dec)); } static byte[] getIV() { String iv = "asdfivh7"; //IV length: must be 8 bytes long return iv.getBytes(); } /** * 生成密钥 * * @return * @throws Exception */ private static byte[] generateKey() throws Exception { KeyGenerator keyGenerator = KeyGenerator.getInstance(KEY_ALGORITHM); keyGenerator.init(56); //des 必须是56, 此初始方法不必须调用 SecretKey secretKey = keyGenerator.generateKey(); return secretKey.getEncoded(); } /** * 还原密钥 * * @param key * @return * @throws Exception */ private static Key toKey(byte[] key) throws Exception { DESKeySpec des = new DESKeySpec(key); SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(KEY_ALGORITHM); SecretKey secretKey = keyFactory.generateSecret(des); return secretKey; } /** * 加密 * @param data 原文 * @param key * @return 密文 * @throws Exception */ public static byte[] encrypt(byte[] data, byte[] key) throws Exception { Key k = toKey(key); Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM_ECB); cipher.init(Cipher.ENCRYPT_MODE, k); return cipher.doFinal(data); } /** * 解密 * @param data 密文 * @param key * @return 明文、原文 * @throws Exception */ public static byte[] decrypt(byte[] data, byte[] key) throws Exception { Key k = toKey(key); Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM_ECB); cipher.init(Cipher.DECRYPT_MODE, k); return cipher.doFinal(data); } } 参考另一篇：Java工具类——DES加密和解密工具 I http://blog.csdn.net/softwave/article/details/12838045
转自【http://www.open-open.com/lib/view/open1394441809958.html】
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