DSA 私钥签名，公钥验签
public static final String ALGORITHM = "DSA";/*** 默认密钥字节数* <pre>* DSA* Default Keysize 1024* Keysize must be a multiple of 64, ranging from 512 to 1024 (inclusive).* </pre>*/private static final int KEY_SIZE = 1024;/*** 默认种子*/private static final String DEFAULT_SEED = "0f22507a10bbddd07d8a3082122966e3";private static final String PUBLIC_KEY = "DSAPublicKey";private static final String PRIVATE_KEY = "DSAPrivateKey";/*** 用私钥对信息生成数字签名* @param data* 加密数据* @param privateKey* 私钥* @return* @throws Exception*/public static String sign(byte[] data, String privateKey) throws Exception {// 解密由base64编码的私钥byte[] keyBytes = decryptBASE64(privateKey);// 构造PKCS8EncodedKeySpec对象PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);// KEY_ALGORITHM 指定的加密算法KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);// 取私钥匙对象PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);// 用私钥对信息生成数字签名Signature signature = Signature.getInstance(keyFactory.getAlgorithm());signature.initSign(priKey);signature.update(data);return encryptBASE64(signature.sign());}/*** BASE64解密* @param key* @return* @throws Exception*/public static byte[] decryptBASE64(String key) throws Exception {return (new BASE64Decoder()).decodeBuffer(key);}/*** BASE64加密* @param key* @return* @throws Exception*/public static String encryptBASE64(byte[] key) throws Exception {return (new BASE64Encoder()).encodeBuffer(key);}/*** 校验数字签名* @param data* 加密数据* @param publicKey* 公钥* @param sign* 数字签名* @return 校验成功返回true 失败返回false* @throws Exception*/public static boolean verify(byte[] data, String publicKey, String sign)throws Exception {// 解密由base64编码的公钥byte[] keyBytes = decryptBASE64(publicKey);// 构造X509EncodedKeySpec对象X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);// ALGORITHM 指定的加密算法KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);// 取公钥匙对象PublicKey pubKey = keyFactory.generatePublic(keySpec);Signature signature = Signature.getInstance(keyFactory.getAlgorithm());signature.initVerify(pubKey);signature.update(data);// 验证签名是否正常return signature.verify(decryptBASE64(sign));}/*** 生成密钥* @param seed* 种子* @return 密钥对象* @throws Exception*/public static Map<String, Object> initKey(String seed) throws Exception {KeyPairGenerator keygen = KeyPairGenerator.getInstance(ALGORITHM);// 初始化随机产生器SecureRandom secureRandom = new SecureRandom();secureRandom.setSeed(seed.getBytes());keygen.initialize(KEY_SIZE, secureRandom);KeyPair keys = keygen.genKeyPair();DSAPublicKey publicKey = (DSAPublicKey) keys.getPublic();DSAPrivateKey privateKey = (DSAPrivateKey) keys.getPrivate();Map<String, Object> map = new HashMap<String, Object>(2);map.put(PUBLIC_KEY, publicKey);map.put(PRIVATE_KEY, privateKey);return map;}/*** 默认生成密钥** @return 密钥对象* @throws Exception*/public static Map<String, Object> initKey() throws Exception {return initKey(DEFAULT_SEED);}/*** 取得私钥** @param keyMap* @return* @throws Exception*/public static String getPrivateKey(Map<String, Object> keyMap)throws Exception {Key key = (Key) keyMap.get(PRIVATE_KEY);return encryptBASE64(key.getEncoded());}/*** 取得公钥** @param keyMap* @return* @throws Exception*/public static String getPublicKey(Map<String, Object> keyMap)throws Exception {Key key = (Key) keyMap.get(PUBLIC_KEY);return encryptBASE64(key.getEncoded());}public static void main(String[] args) throws Exception {String inputStr = "abc";byte[] data = inputStr.getBytes();// 构建密钥Map<String, Object> keyMap = initKey();// 获得密钥String publicKey = getPublicKey(keyMap);String privateKey = getPrivateKey(keyMap);System.err.println("公钥:\r" + publicKey);System.err.println("私钥:\r" + privateKey);// 产生签名String sign = sign(data, privateKey);System.err.println("签名:\r" + sign);// 验证签名boolean status = verify(data, publicKey, sign);System.err.println("状态:\r" + status);}
