Rsa加密类

需要导入Base64.jar包

import java.io.ByteArrayOutputStream;
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.Signature;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

import javax.crypto.Cipher;

import Decoder.BASE64Decoder;
import Decoder.BASE64Encoder;

public class RSACrypt {

   /**
    * 文件读取缓冲区大小
    */
   private static final int CACHE_SIZE = 1024;

   /**
    * <p>
    * BASE64字符串解码为二进制数据
    * </p>
    *
    * @param base64
    * @return
    * @throws Exception
    */
   public static byte[] decode(String base64) throws Exception {
      return new BASE64Decoder().decodeBuffer(base64);
   }

   /**
    * <p>
    * 二进制数据编码为BASE64字符串
    * </p>
    *
    * @param bytes
    * @return
    * @throws Exception
    */
   public static String encode(byte[] bytes) throws Exception {
      return new BASE64Encoder().encode(bytes);
   }

   /**
    * 加密算法RSA
    */
   // public static final String KEY_ALGORITHM = "RSA";

   public static final String KEY_ALGORITHM = "RSA";

   /**
    * 签名算法
    */
   public static final String SIGNATURE_ALGORITHM = "MD5withRSA";

   /**
    * 获取公钥的key
    */
   private static final String PUBLIC_KEY = "RSAPublicKey";

   /**
    * 获取私钥的key
    */
   private static final String PRIVATE_KEY = "RSAPrivateKey";

   /**
    * RSA最大加密明文大小
    */
   private static final int MAX_ENCRYPT_BLOCK = 117;

   /**
    * RSA最大解密密文大小
    */
   private static final int MAX_DECRYPT_BLOCK = 128;

   /**
    * <p>
    * 生成密钥对(公钥和私钥)
    * </p>
    *
    * @return
    * @throws Exception
    */
   public static Map<String, Object> genKeyPair() throws Exception {
      KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
      keyPairGen.initialize(1024);
      KeyPair keyPair = keyPairGen.generateKeyPair();
      RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
      RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
      Map<String, Object> keyMap = new HashMap<String, Object>(2);
      keyMap.put(PUBLIC_KEY, publicKey);
      keyMap.put(PRIVATE_KEY, privateKey);
      return keyMap;
   }

   /**
    * <p>
    * 生成密钥对(公钥和私钥)
    * </p>
    *
    * @return
    * @throws Exception
    */
   public static Map<String, Object> genKeyPair(String seed) throws Exception {
      KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
      keyPairGen.initialize(1024);
      // SecureRandom secrand = new SecureRandom();
      // secrand.setSeed(seed.getBytes()); // 初始化随机产生器
      // keyPairGen.initialize(1024, secrand);
      KeyPair keyPair = keyPairGen.generateKeyPair();
      RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
      RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
      Map<String, Object> keyMap = new HashMap<String, Object>(2);
      keyMap.put(PUBLIC_KEY, publicKey);
      keyMap.put(PRIVATE_KEY, privateKey);
      return keyMap;
   }

   /**
    * <p>
    * 用私钥对信息生成数字签名
    * </p>
    *
    * @param data
    *            已加密数据
    * @param privateKey
    *            私钥(BASE64编码)
    *
    * @return
    * @throws Exception
    */
   public static String sign(byte[] data, String privateKey) throws Exception {
      byte[] keyBytes = decode(privateKey);
      PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
      KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
      PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
      Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
      signature.initSign(privateK);
      signature.update(data);
      return encode(signature.sign());
   }

   /**
    * <p>
    * 校验数字签名
    * </p>
    *
    * @param data
    *            已加密数据
    * @param publicKey
    *            公钥(BASE64编码)
    * @param sign
    *            数字签名
    *
    * @return
    * @throws Exception
    *
    */
   public static boolean verify(byte[] data, String publicKey, String sign) throws Exception {
      byte[] keyBytes = decode(publicKey);
      X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
      KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);

      PublicKey publicK = keyFactory.generatePublic(keySpec);
      Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
      signature.initVerify(publicK);
      signature.update(data);
      return signature.verify(decode(sign));
   }

   /**
    * <P>
    * 私钥解密
    * </p>
    *
    * @param encryptedData
    *            已加密数据
    * @param privateKey
    *            私钥(BASE64编码)
    * @return
    * @throws Exception
    */
   public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey) throws Exception {
      byte[] keyBytes = decode(privateKey);
      PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
      KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
      Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
//     Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());

      Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1PADDING");

      cipher.init(Cipher.DECRYPT_MODE, privateK);
      int inputLen = encryptedData.length;
      ByteArrayOutputStream out = new ByteArrayOutputStream();
      int offSet = 0;
      byte[] cache;
      int i = 0;
      // 对数据分段解密
      while (inputLen - offSet > 0) {
         if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
            cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
         } else {
            cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
         }
         out.write(cache, 0, cache.length);
         i++;
         offSet = i * MAX_DECRYPT_BLOCK;
      }
      byte[] decryptedData = out.toByteArray();
      out.close();
      return decryptedData;
   }

   /**
    * <p>
    * 公钥解密
    * </p>
    *
    * @param encryptedData
    *            已加密数据
    * @param publicKey
    *            公钥(BASE64编码)
    * @return
    * @throws Exception
    */
   public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey) throws Exception {
      byte[] keyBytes = decode(publicKey);
      X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
      KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
      Key publicK = keyFactory.generatePublic(x509KeySpec);
      // Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());

      Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1PADDING");
      cipher.init(Cipher.DECRYPT_MODE, publicK);
      int inputLen = encryptedData.length;
      ByteArrayOutputStream out = new ByteArrayOutputStream();
      int offSet = 0;
      byte[] cache;
      int i = 0;
      // 对数据分段解密
      while (inputLen - offSet > 0) {
         if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
            cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
         } else {
            cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
         }
         out.write(cache, 0, cache.length);
         i++;
         offSet = i * MAX_DECRYPT_BLOCK;
      }
      byte[] decryptedData = out.toByteArray();
      out.close();
      return decryptedData;
   }

   /**
    * <p>
    * 公钥加密
    * </p>
    *
    * @param data
    *            源数据
    * @param publicKey
    *            公钥(BASE64编码)
    * @return
    * @throws Exception
    */
   public static byte[] encryptByPublicKey(byte[] data, String publicKey) throws Exception {
      byte[] keyBytes = decode(publicKey);
      X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
      KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
      Key publicK = keyFactory.generatePublic(x509KeySpec);
      // 对数据加密
      // Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());

      Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1PADDING");

      cipher.init(Cipher.ENCRYPT_MODE, publicK);
      int inputLen = data.length;
      ByteArrayOutputStream out = new ByteArrayOutputStream();
      int offSet = 0;
      byte[] cache;
      int i = 0;
      // 对数据分段加密
      while (inputLen - offSet > 0) {
         if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
            cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
         } else {
            cache = cipher.doFinal(data, offSet, inputLen - offSet);
         }
         out.write(cache, 0, cache.length);
         i++;
         offSet = i * MAX_ENCRYPT_BLOCK;
      }
      byte[] encryptedData = out.toByteArray();
      out.close();
      return encryptedData;
   }

   /**
    * <p>
    * 私钥加密
    * </p>
    *
    * @param data
    *            源数据
    * @param privateKey
    *            私钥(BASE64编码)
    * @return
    * @throws Exception
    */
   public static byte[] encryptByPrivateKey(byte[] data, String privateKey) throws Exception {
      byte[] keyBytes = decode(privateKey);
      PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
      KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
      Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
      // Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
      Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1PADDING");
      cipher.init(Cipher.ENCRYPT_MODE, privateK);
      int inputLen = data.length;
      ByteArrayOutputStream out = new ByteArrayOutputStream();
      int offSet = 0;
      byte[] cache;
      int i = 0;
      // 对数据分段加密
      while (inputLen - offSet > 0) {
         if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
            cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
         } else {
            cache = cipher.doFinal(data, offSet, inputLen - offSet);
         }
         out.write(cache, 0, cache.length);
         i++;
         offSet = i * MAX_ENCRYPT_BLOCK;
      }
      byte[] encryptedData = out.toByteArray();
      out.close();
      return encryptedData;
   }

   /**
    * <p>
    * 获取私钥
    * </p>
    *
    * @param keyMap
    *            密钥对
    * @return
    * @throws Exception
    */
   public static String getPrivateKey(Map<String, Object> keyMap) throws Exception {
      Key key = (Key) keyMap.get(PRIVATE_KEY);
      return encode(key.getEncoded());
   }

   /**
    * <p>
    * 获取公钥
    * </p>
    *
    * @param keyMap
    *            密钥对
    * @return
    * @throws Exception
    */
   public static String getPublicKey(Map<String, Object> keyMap) throws Exception {
      Key key = (Key) keyMap.get(PUBLIC_KEY);
      return encode(key.getEncoded());
   }

}
________________________________________
public class Rsademo {
   public static void main(String[] args) {
      try {
         String privateKey = "MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoGBAKB8GunT65dDzvV4" + "VD6UA9+lGEjIgEtyEVtrp3rEhBRmvOZ1sromkybrAF4ByodHh1BmgBLdImMqMzH2"
               + "vgwc3ioOqiaODqHNPpqa/jeSrdNE/hJSKQqPXi+qVaIg6tOi84GnirHOrwkVxR45" + "kQgj4lH7qnIaMhooaIModIsDTGs7AgMBAAECgYEAg/Jlwlhtu9mRgDslsKnLoYZA"
               + "uB65dM5dPPf/JC4MliV+LFEa2Hg8xmOy0pfQZ3dE5rLPnDLaQgQBQZQn3xehBE/N" + "2YdzLEH1Dpw1eOJY30Qf/Rp6jUaTwY5gQCxSDt24CXpDjzo09dvaR4uHhRNZX1KB"
               + "XNco+PiM7ujFaSrhuBkCQQDQC3d2OhQB4vAaxaPzwqQv6lAFWCR8Osy5jyY/KlVF" + "kd/VzXp2uWACgFm6UXmUwyLfrSpFl013E5SjOsdgpXYNAkEAxXoqed1TYAHHS63N"
               + "oIQlMz/ygHiMtkFeoD8HgKYw5TzYCpqlM++2O1VcbTLjQtnwctIe3B3xF7eOZ1Si" + "53KcZwJAdPaNYhWC3BCnJpYI9+ls/1c/R9HnKUSxhn05Zne5WxSJAB22hPrxRFa+"
               + "m2Zk8ULH33LuehN3RMPoY+CO6QH9HQJBAK9+JrtP7iU2z2a42TEZ3nlSDe8PsnTR" + "WQdtm/w/NNqznIan8cJa+AZ4kH/WplIlneJcSuJwlW3vSNUZSQAIQWcCQHBsB41q"
               + "WyyPcRBjMCR6YO4Iih/07kZJDAqHrdnhea+aNF+MPuShqIGlcDEbdeS1XxUp8gSm" + "diXEh5aJvpTfSEY=";

         String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCgfBrp0+uXQ871eFQ+lAPfpRhI" + "yIBLchFba6d6xIQUZrzmdbK6JpMm6wBeAcqHR4dQZoAS3SJjKjMx9r4MHN4qDqom"
               + "jg6hzT6amv43kq3TRP4SUikKj14vqlWiIOrTovOBp4qxzq8JFcUeOZEII+JR+6py" + "GjIaKGiDKHSLA0xrOwIDAQAB";

         System.out.println("privateKey=" + privateKey);
         System.err.println("私钥加密——公钥解密");
         String source = "hyx_912_74571852356eb1dd4902f66c9c7ad103e8285d010d27488b";
         System.out.println("原文字：\r\n" + source);
         byte[] data = source.getBytes();
         // byte[] encodedData = RSACrypt.encryptByPrivateKey(data, privateKey);
         byte[] encodedData = RSACrypt.encryptByPublicKey(data, publicKey);
         String enBaseDate = RSACrypt.encode(encodedData);
         System.out.println("加密后：\r\n" + enBaseDate);
         // byte[] decryptByPublicKey = RSACrypt.decryptByPublicKey(encodedData, publicKey);
         byte[] decryptByPublicKey = RSACrypt.decryptByPrivateKey(encodedData, privateKey);
         System.out.println("解密后：\r\n" + new String(decryptByPublicKey));
      } catch (Exception e) {
         e.printStackTrace();
      }

   }
}