Java加密算法DES

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标准的文档地址(click me)
密钥加密也称为对称加密，速度快，但加密和解密的钥匙必须相同，只有通信双方才能知道钥匙
package com.stone.security;import java.security.Key;import java.security.SecureRandom;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(generateKey());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 longreturn 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, new SecureRandom());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, new SecureRandom());return cipher.doFinal(data);}}
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