Java加密算法 DSA 和 数字签名，加密算法dsa,import java.

Java加密算法 DSA 和 数字签名，加密算法dsa,import java.

import java.security.Key;  import java.security.KeyFactory;  import java.security.KeyPair;  import java.security.KeyPairGenerator;  import java.security.PrivateKey;  import java.security.PublicKey;  import java.security.SecureRandom;  import java.security.Signature;  import java.security.spec.PKCS8EncodedKeySpec;  import java.security.spec.X509EncodedKeySpec;  import java.util.HashMap;  import java.util.Map;  import sun.misc.BASE64Decoder;  import sun.misc.BASE64Encoder;  /**  * DSA-Digital Signature Algorithm 是Schnorr和ElGamal签名算法的变种，被美国NIST作为DSS(DigitalSignature Standard)。  * 简单的说，这是一种更高级的验证方式，用作数字签名。不单单只有公钥、私钥，还有数字签名。私钥加密生成数字签名，公钥验证数据及签名。  * 如果数据和签名不匹配则认为验证失败！即 传输中的数据 可以不再加密，接收方获得数据后，拿到公钥与签名 验证数据是否有效  *   * @author stone  * @date 2014-03-11 09:50:51  */  public class DSA {      //不仅可以使用DSA算法，同样也可以使用RSA算法做数字签名      /*public static final String KEY_ALGORITHM = "RSA";     public static final String SIGNATURE_ALGORITHM = "MD5withRSA";*/      public static final String KEY_ALGORITHM = "DSA";      public static final String SIGNATURE_ALGORITHM = "DSA";      public static final String DEFAULT_SEED = "$%^*%^()(HJG8awfjas7"; //默认种子      public static final String PUBLIC_KEY = "DSAPublicKey";      public static final String PRIVATE_KEY = "DSAPrivateKey";      public static void main(String[] args) throws Exception {          String str = "!@#$!#^$#&amp;ZXVDF呆军工路爱着你*()_+";          byte[] data = str.getBytes();          Map<String, Object> keyMap = initKey();// 构建密钥          PublicKey publicKey = (PublicKey) keyMap.get(PUBLIC_KEY);          PrivateKey privateKey = (PrivateKey) keyMap.get(PRIVATE_KEY);          System.out.println("私钥format：" + privateKey.getFormat());          System.out.println("公钥format：" + publicKey.getFormat());          // 产生签名          String sign = sign(data, getPrivateKey(keyMap));          // 验证签名           boolean verify1 = verify("aaa".getBytes(), getPublicKey(keyMap), sign);          System.err.println("经验证 数据和签名匹配:" + verify1);             boolean verify = verify(data, getPublicKey(keyMap), sign);          System.err.println("经验证 数据和签名匹配:" + verify);         }      /**        * 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 {          System.out.println("生成密钥");          KeyPairGenerator keygen = KeyPairGenerator.getInstance(KEY_ALGORITHM);          SecureRandom secureRandom = new SecureRandom();             secureRandom.setSeed(seed.getBytes());           //Modulus size must range from 512 to 1024 and be a multiple of 64          keygen.initialize(640, secureRandom);            KeyPair keys = keygen.genKeyPair();          PrivateKey privateKey = keys.getPrivate();          PublicKey publicKey = keys.getPublic();          Map<String, Object> map = new HashMap<String, Object>(2);          map.put(PUBLIC_KEY, publicKey);             map.put(PRIVATE_KEY, privateKey);          return map;      }      /**        * 生成默认密钥        *         * @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()); //base64加密私钥      }         /**        * 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()); //base64加密公钥      }         /**      *  用私钥对信息进行数字签名      * @param data  加密数据      * @param privateKey 私钥-base64加密的      * @return       * @throws Exception      */      public static String sign(byte[] data, String privateKey) throws Exception {          System.out.println("用私钥对信息进行数字签名");          byte[] keyBytes = decryptBASE64(privateKey);          PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);          KeyFactory factory = KeyFactory.getInstance(KEY_ALGORITHM);          PrivateKey priKey = factory.generatePrivate(keySpec);//生成 私钥          //用私钥对信息进行数字签名          Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);          signature.initSign(priKey);          signature.update(data);          return encryptBASE64(signature.sign());      }      /**      * BASE64Encoder 加密      * @param data 要加密的数据      * @return 加密后的字符串      */      private static String encryptBASE64(byte[] data) {          BASE64Encoder encoder = new BASE64Encoder();          String encode = encoder.encode(data);          return encode;      }      /**      * BASE64Decoder 解密      * @param data 要解密的字符串      * @return 解密后的byte[]      * @throws Exception       */      private static byte[] decryptBASE64(String data) throws Exception {          BASE64Decoder decoder = new BASE64Decoder();          byte[] buffer = decoder.decodeBuffer(data);          return buffer;      }      /**      * 校验数字签名      * @param data 加密数据      * @param publicKey      * @param sign 数字签名      * @return      * @throws Exception      */      public static boolean verify(byte[] data, String publicKey, String sign) throws Exception {          byte[] keyBytes = decryptBASE64(publicKey);           X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);          KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);            PublicKey pubKey = keyFactory.generatePublic(keySpec);          Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);             signature.initVerify(pubKey);           signature.update(data);          return signature.verify(decryptBASE64(sign)); //验证签名      }  }