java之RSA和Base64加密帮助类

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1、RSAUtils.java类

package com.sangfor.vpn.client.service.utils;import java.io.BufferedReader;  import java.io.ByteArrayOutputStream;  import java.io.IOException;  import java.io.InputStream;  import java.io.InputStreamReader;  import java.math.BigInteger;  import java.security.KeyFactory;  import java.security.KeyPair;  import java.security.KeyPairGenerator;  import java.security.NoSuchAlgorithmException;  import java.security.PrivateKey;  import java.security.PublicKey;  import java.security.interfaces.RSAPrivateKey;  import java.security.interfaces.RSAPublicKey;  import java.security.spec.InvalidKeySpecException;  import java.security.spec.PKCS8EncodedKeySpec;  import java.security.spec.RSAPublicKeySpec;  import java.security.spec.X509EncodedKeySpec;    import javax.crypto.Cipher;    /**  * Created by wk on 2017/2/14.  */    public class RSAUtils {      private static String RSA = "RSA";      /** *//**       * RSA最大加密明文大小       */        private static final int MAX_ENCRYPT_BLOCK = 117;        /**      * 随机生成RSA密钥对(默认密钥长度为1024)      *      * @return      */      public static KeyPair generateRSAKeyPair()      {          return generateRSAKeyPair(1024);      }        /**      * 随机生成RSA密钥对      *      * @param keyLength      *            密钥长度,范围:512~2048<br>      *            一般1024      * @return      */      public static KeyPair generateRSAKeyPair(int keyLength)      {          try          {              KeyPairGenerator kpg = KeyPairGenerator.getInstance(RSA);              kpg.initialize(keyLength);              return kpg.genKeyPair();          } catch (NoSuchAlgorithmException e)          {              e.printStackTrace();              return null;          }      }        /**      * 用公钥加密 <br>      * 每次加密的字节数,不能超过密钥的长度值减去11      *      * @param data      *            需加密数据的byte数据      * @param publicKey 公钥      * @return 加密后的byte型数据      */      public static byte[] encryptData(byte[] data, PublicKey publicKey)      {                    try          {              Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");              // 编码前设定编码方式及密钥              cipher.init(Cipher.ENCRYPT_MODE, publicKey);              // 传入编码数据并返回编码结果              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;            } catch (Exception e)          {              e.printStackTrace();              return null;          }      }        /**      * 用私钥解密      *      * @param encryptedData      *            经过encryptedData()加密返回的byte数据      * @param privateKey      *            私钥      * @return      */      public static byte[] decryptData(byte[] encryptedData, PrivateKey privateKey)      {          try          {              Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");              cipher.init(Cipher.DECRYPT_MODE, privateKey);              return cipher.doFinal(encryptedData);          } catch (Exception e)          {                 e.printStackTrace();              return null;          }      }        /**      * 通过公钥byte[](publicKey.getEncoded())将公钥还原,适用于RSA算法      *      * @param keyBytes      * @return      * @throws NoSuchAlgorithmException      * @throws InvalidKeySpecException      */      public static PublicKey getPublicKey(byte[] keyBytes) throws NoSuchAlgorithmException,              InvalidKeySpecException      {          X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);          KeyFactory keyFactory = KeyFactory.getInstance(RSA);          PublicKey publicKey = keyFactory.generatePublic(keySpec);          return publicKey;      }        /**      * 通过私钥byte[]将公钥还原,适用于RSA算法      *      * @param keyBytes      * @return      * @throws NoSuchAlgorithmException      * @throws InvalidKeySpecException      */      public static PrivateKey getPrivateKey(byte[] keyBytes) throws NoSuchAlgorithmException,              InvalidKeySpecException      {          PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);          KeyFactory keyFactory = KeyFactory.getInstance(RSA);          PrivateKey privateKey = keyFactory.generatePrivate(keySpec);          return privateKey;      }        /**      * 使用N、e值还原公钥      *      * @param modulus      * @param publicExponent      * @return      * @throws NoSuchAlgorithmException      * @throws InvalidKeySpecException      */      public static PublicKey getPublicKey(String modulus, String publicExponent)              throws NoSuchAlgorithmException, InvalidKeySpecException      {          BigInteger bigIntModulus = new BigInteger(modulus);          BigInteger bigIntPrivateExponent = new BigInteger(publicExponent);          RSAPublicKeySpec keySpec = new RSAPublicKeySpec(bigIntModulus, bigIntPrivateExponent);          KeyFactory keyFactory = KeyFactory.getInstance(RSA);          PublicKey publicKey = keyFactory.generatePublic(keySpec);          return publicKey;      }        /**      * 使用N、d值还原私钥      *      * @param modulus      * @param privateExponent      * @return      * @throws NoSuchAlgorithmException      * @throws InvalidKeySpecException      */      public static PrivateKey getPrivateKey(String modulus, String privateExponent)              throws NoSuchAlgorithmException, InvalidKeySpecException      {          BigInteger bigIntModulus = new BigInteger(modulus);          BigInteger bigIntPrivateExponent = new BigInteger(privateExponent);          RSAPublicKeySpec keySpec = new RSAPublicKeySpec(bigIntModulus, bigIntPrivateExponent);          KeyFactory keyFactory = KeyFactory.getInstance(RSA);          PrivateKey privateKey = keyFactory.generatePrivate(keySpec);          return privateKey;      }        /**      * 从字符串中加载公钥      *      * @param publicKeyStr      *            公钥数据字符串      * @throws Exception      *             加载公钥时产生的异常      */      public static PublicKey loadPublicKey(String publicKeyStr) throws Exception      {          try          {              byte[] buffer = Base64Utils.decode(publicKeyStr);              KeyFactory keyFactory = KeyFactory.getInstance(RSA);              X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);              return (RSAPublicKey) keyFactory.generatePublic(keySpec);          } catch (NoSuchAlgorithmException e)          {              throw new Exception("无此算法");          } catch (InvalidKeySpecException e)          {              throw new Exception("公钥非法");          } catch (NullPointerException e)          {              throw new Exception("公钥数据为空");          }      }        /**      * 从字符串中加载私钥<br>      * 加载时使用的是PKCS8EncodedKeySpec(PKCS#8编码的Key指令)。      *      * @param privateKeyStr      * @return      * @throws Exception      */      public static PrivateKey loadPrivateKey(String privateKeyStr) throws Exception      {          try          {              byte[] buffer = Base64Utils.decode(privateKeyStr);              // X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);              PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(buffer);              KeyFactory keyFactory = KeyFactory.getInstance(RSA);              return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);          } catch (NoSuchAlgorithmException e)          {              throw new Exception("无此算法");          } catch (InvalidKeySpecException e)          {              throw new Exception("私钥非法");          } catch (NullPointerException e)          {              throw new Exception("私钥数据为空");          }      }        /**      * 从文件中输入流中加载公钥      *      * @param in      *            公钥输入流      * @throws Exception      *             加载公钥时产生的异常      */      public static PublicKey loadPublicKey(InputStream in) throws Exception      {          try          {              return loadPublicKey(readKey(in));          } catch (IOException e)          {              throw new Exception("公钥数据流读取错误");          } catch (NullPointerException e)          {              throw new Exception("公钥输入流为空");          }      }        /**      * 从文件中加载私钥      *      * @param in      *            私钥文件名      * @return 是否成功      * @throws Exception      */      public static PrivateKey loadPrivateKey(InputStream in) throws Exception      {          try          {              return loadPrivateKey(readKey(in));          } catch (IOException e)          {              throw new Exception("私钥数据读取错误");          } catch (NullPointerException e)          {              throw new Exception("私钥输入流为空");          }      }        /**      * 读取密钥信息      *      * @param in      * @return      * @throws IOException      */      private static String readKey(InputStream in) throws IOException      {          BufferedReader br = new BufferedReader(new InputStreamReader(in));          String readLine = null;          StringBuilder sb = new StringBuilder();          while ((readLine = br.readLine()) != null)          {              if (readLine.charAt(0) == '-')              {                  continue;              } else              {                  sb.append(readLine);                  sb.append('\r');              }          }            return sb.toString();      }        /**      * 打印公钥信息      *      * @param publicKey      */      public static void printPublicKeyInfo(PublicKey publicKey)      {          RSAPublicKey rsaPublicKey = (RSAPublicKey) publicKey;          System.out.println("----------RSAPublicKey----------");          System.out.println("Modulus.length=" + rsaPublicKey.getModulus().bitLength());          System.out.println("Modulus=" + rsaPublicKey.getModulus().toString());          System.out.println("PublicExponent.length=" + rsaPublicKey.getPublicExponent().bitLength());          System.out.println("PublicExponent=" + rsaPublicKey.getPublicExponent().toString());      }        public static void printPrivateKeyInfo(PrivateKey privateKey)      {          RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) privateKey;          System.out.println("----------RSAPrivateKey ----------");          System.out.println("Modulus.length=" + rsaPrivateKey.getModulus().bitLength());          System.out.println("Modulus=" + rsaPrivateKey.getModulus().toString());          System.out.println("PrivateExponent.length=" + rsaPrivateKey.getPrivateExponent().bitLength());          System.out.println("PrivatecExponent=" + rsaPrivateKey.getPrivateExponent().toString());        }  }  





2、Base64Utils.java类

package com.sangfor.vpn.client.service.utils;import java.io.UnsupportedEncodingException;  /**  * Created by wk on 2017/2/14.  */    public class Base64Utils {      private static char[] base64EncodeChars = new char[]              { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',                      'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',                      'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5',                      '6', '7', '8', '9', '+', '/' };      private static byte[] base64DecodeChars = new byte[]              { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,                      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53,                      54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,                      12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29,                      30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1,                      -1, -1, -1 };        /**      * 加密      *      * @param data      * @return      */      public static String encode(byte[] data)      {          StringBuffer sb = new StringBuffer();          int len = data.length;          int i = 0;          int b1, b2, b3;          while (i < len)          {              b1 = data[i++] & 0xff;              if (i == len)              {                  sb.append(base64EncodeChars[b1 >>> 2]);                  sb.append(base64EncodeChars[(b1 & 0x3) << 4]);                  sb.append("==");                  break;              }              b2 = data[i++] & 0xff;              if (i == len)              {                  sb.append(base64EncodeChars[b1 >>> 2]);                  sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);                  sb.append(base64EncodeChars[(b2 & 0x0f) << 2]);                  sb.append("=");                  break;              }              b3 = data[i++] & 0xff;              sb.append(base64EncodeChars[b1 >>> 2]);              sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);              sb.append(base64EncodeChars[((b2 & 0x0f) << 2) | ((b3 & 0xc0) >>> 6)]);              sb.append(base64EncodeChars[b3 & 0x3f]);          }          return sb.toString();      }        /**      * 解密      *      * @param str      * @return      */      public static byte[] decode(String str)      {          try          {              return decodePrivate(str);          } catch (UnsupportedEncodingException e)          {              e.printStackTrace();          }          return new byte[]                  {};      }        private static byte[] decodePrivate(String str) throws UnsupportedEncodingException      {          StringBuffer sb = new StringBuffer();          byte[] data = null;          data = str.getBytes("US-ASCII");          int len = data.length;          int i = 0;          int b1, b2, b3, b4;          while (i < len)          {                do              {                  b1 = base64DecodeChars[data[i++]];              } while (i < len && b1 == -1);              if (b1 == -1)                  break;                do              {                  b2 = base64DecodeChars[data[i++]];              } while (i < len && b2 == -1);              if (b2 == -1)                  break;              sb.append((char) ((b1 << 2) | ((b2 & 0x30) >>> 4)));                do              {                  b3 = data[i++];                  if (b3 == 61)                      return sb.toString().getBytes("iso8859-1");                  b3 = base64DecodeChars[b3];              } while (i < len && b3 == -1);              if (b3 == -1)                  break;              sb.append((char) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));                do              {                  b4 = data[i++];                  if (b4 == 61)                      return sb.toString().getBytes("iso8859-1");                  b4 = base64DecodeChars[b4];              } while (i < len && b4 == -1);              if (b4 == -1)                  break;              sb.append((char) (((b3 & 0x03) << 6) | b4));          }          return sb.toString().getBytes("iso8859-1");      }    }  


3、SecurityUtils类

package com.sangfor.vpn.client.service.utils;import java.io.FileInputStream;  import java.io.FileNotFoundException;  import java.io.InputStream;  import java.security.PrivateKey;  import java.security.PublicKey;    public class SecurityUtils {      /**      * 解密      * @param cipherText 密文      * @return 返回解密后的字符串      * @throws Exception       */      public static String decrypt(String cipherText) throws Exception{           // 从文件中得到私钥          FileInputStream inPrivate = new FileInputStream(                  SecurityUtils.class.getClassLoader().getResource("").getPath() + "/pkcs8_private_key.pem");          PrivateKey privateKey = RSAUtils.loadPrivateKey(inPrivate);          byte[] decryptByte = RSAUtils.decryptData(Base64Utils.decode(cipherText), privateKey);          String decryptStr = new String(decryptByte,"utf-8");          return decryptStr;      }      /**      * 加密      * @param plainTest 明文      * @return  返回加密后的密文      * @throws Exception       */      public static String encrypt(String plainTest) throws Exception{          PublicKey publicKey = RSAUtils.loadPublicKey(plainTest);          // 加密          byte[] encryptByte = RSAUtils.encryptData(plainTest.getBytes(), publicKey);          String afterencrypt = Base64Utils.encode(encryptByte);          return afterencrypt;      }          /**      * 加密      * @param plainTest 明文      * @return  返回加密后的密文      * @throws Exception       */      public static String encrypt(String plainTest, String key) throws Exception{          PublicKey publicKey = RSAUtils.loadPublicKey(key);          // 加密          byte[] encryptByte = RSAUtils.encryptData(plainTest.getBytes(), publicKey);          String afterencrypt = Base64Utils.encode(encryptByte);          return afterencrypt;      }  }  








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