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Java 加解密技术系列之 DES
import com.google.common.base.Strings; import sun.misc.BASE64Decoder; import sun.misc.BASE64Encoder; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey; import javax.crypto.SecretKeyFactory; import javax.crypto.spec.DESKeySpec; import java.security.InvalidKeyException; import java.security.Key; import java.security.NoSuchAlgorithmException; import java.security.SecureRandom; import java.security.spec.InvalidKeySpecException; /** * Created by xiang.li on 2015/2/28. * DES 加解密工具类 * * <pre> * 支持 DES、DESede(TripleDES,就是3DES)、AES、Blowfish、RC2、RC4(ARCFOUR) * DES key size must be equal to 56 * DESede(TripleDES) key size must be equal to 112 or 168 * AES key size must be equal to 128, 192 or 256,but 192 and 256 bits may not be available * Blowfish key size must be multiple of 8, and can only range from 32 to 448 (inclusive) * RC2 key size must be between 40 and 1024 bits * RC4(ARCFOUR) key size must be between 40 and 1024 bits * 具体内容 需要关注 JDK Document http://.../docs/technotes/guides/security/SunProviders.html * </pre> */ public class DES { /** * 定义加密方式 */ private final static String KEY_DES = "DES"; private final static String KEY_AES = "AES"; // 测试 /** * 全局数组 */ private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" }; /** * 初始化密钥 * @return */ public static String init() { return init(null); } /** * 初始化密钥 * @param seed 初始化参数 * @return */ public static String init(String seed) { SecureRandom secure = null; String str = ""; try { if (null != secure) { // 带参数的初始化 secure = new SecureRandom(decryptBase64(seed)); } else { // 不带参数的初始化 secure = new SecureRandom(); } KeyGenerator generator = KeyGenerator.getInstance(KEY_DES); generator.init(secure); SecretKey key = generator.generateKey(); str = encryptBase64(key.getEncoded()); } catch (Exception e) { e.printStackTrace(); } return str; } /** * 转换密钥 * @param key 密钥的字节数组 * @return */ private static Key byteToKey(byte[] key) { SecretKey secretKey = null; try { DESKeySpec dks = new DESKeySpec(key); SecretKeyFactory factory = SecretKeyFactory.getInstance(KEY_DES); secretKey = factory.generateSecret(dks); // 当使用其他对称加密算法时，如AES、Blowfish等算法时，用下述代码替换上述三行代码 // secretKey = new SecretKeySpec(key, KEY_DES); } catch (InvalidKeyException e) { e.printStackTrace(); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } catch (InvalidKeySpecException e) { e.printStackTrace(); } return secretKey; } /** * DES 解密 * @param data 需要解密的字符串 * @param key 密钥 * @return */ public static String decryptDES(String data, String key) { // 验证传入的字符串 if (Strings.isNullOrEmpty(data)) { return ""; } // 调用解密方法完成解密 byte[] bytes = decryptDES(hexString2Bytes(data), key); // 将得到的字节数组变成字符串返回 return new String(bytes); } /** * DES 解密 * @param data 需要解密的字节数组 * @param key 密钥 * @return */ public static byte[] decryptDES(byte[] data, String key) { byte[] bytes = null; try { Key k = byteToKey(decryptBase64(key)); Cipher cipher = Cipher.getInstance(KEY_DES); cipher.init(Cipher.DECRYPT_MODE, k); bytes = cipher.doFinal(data); } catch (Exception e) { e.printStackTrace(); } return bytes; } /** * DES 加密 * @param data 需要加密的字符串 * @param key 密钥 * @return */ public static String encryptDES(String data, String key) { // 验证传入的字符串 if (Strings.isNullOrEmpty(data)) { return ""; } // 调用加密方法完成加密 byte[] bytes = encryptDES(data.getBytes(), key); // 将得到的字节数组变成字符串返回 return byteArrayToHexString(bytes); } /** * DES 加密 * @param data 需要加密的字节数组 * @param key 密钥 * @return */ public static byte[] encryptDES(byte[] data, String key) { byte[] bytes = null; try { Key k = byteToKey(decryptBase64(key)); Cipher cipher = Cipher.getInstance(KEY_DES); cipher.init(Cipher.ENCRYPT_MODE, k); bytes = cipher.doFinal(data); } catch (Exception e) { e.printStackTrace(); } return bytes; } /** * BASE64 解密 * @param key 需要解密的字符串 * @return 字节数组 * @throws Exception */ public static byte[] decryptBase64(String key) throws Exception { return (new BASE64Decoder()).decodeBuffer(key); } /** * BASE64 加密 * @param key 需要加密的字节数组 * @return 字符串 * @throws Exception */ public static String encryptBase64(byte[] key) throws Exception { return (new BASE64Encoder()).encodeBuffer(key); } /** * 将一个字节转化成十六进制形式的字符串 * @param b 字节数组 * @return 字符串 */ private static String byteToHexString(byte b) { int ret = b; //System.out.println("ret = " + ret); if (ret < 0) { ret += 256; } int m = ret / 16; int n = ret % 16; return hexDigits[m] + hexDigits[n]; } /** * 转换字节数组为十六进制字符串 * @param bytes 字节数组 * @return 十六进制字符串 */ private static String byteArrayToHexString(byte[] bytes) { StringBuffer sb = new StringBuffer(); for (int i = 0; i < bytes.length; i++) { sb.append(byteToHexString(bytes[i])); } return sb.toString(); } /** * 转换十六进制字符串为字节数组 * @param hexstr 十六进制字符串 * @return */ public static byte[] hexString2Bytes(String hexstr) { byte[] b = new byte[hexstr.length() / 2]; int j = 0; for (int i = 0; i < b.length; i++) { char c0 = hexstr.charAt(j++); char c1 = hexstr.charAt(j++); b[i] = (byte) ((parse(c0) << 4) | parse(c1)); } return b; } /** * 转换字符类型数据为整型数据 * @param c 字符 * @return */ private static int parse(char c) { if (c >= ‘a‘) return (c - ‘a‘ + 10) & 0x0f; if (c >= ‘A‘) return (c - ‘A‘ + 10) & 0x0f; return (c - ‘0‘) & 0x0f; } /** * 测试方法 * @param args */ public static void main(String[] args) { String key = DES.init(); System.out.println("DES密钥:\n" + key); String word = "123"; String encWord = encryptDES(word, key); System.out.println(word + "\n加密后：\n" + encWord); System.out.println(word + "\n解密后：\n" + decryptDES(encWord, key)); } }
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原文地址：http://www.cnblogs.com/crazylqy/p/5178142.html
