加密、解密

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DES 加密解密：

1.先定义一个base64类：

package shared;import java.io.ByteArrayOutputStream;  import java.io.IOException;  import java.io.OutputStream;     public class Base64 {      private static final char[] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();      /**      * data[]进行编码      * @param data      * @return      */          public static String encode(byte[] data) {              int start = 0;              int len = data.length;              StringBuffer buf = new StringBuffer(data.length * 3 / 2);               int end = len - 3;              int i = start;              int n = 0;                while (i <= end) {                  int d = ((((int) data[i]) & 0x0ff) << 16)  | ((((int) data[i + 1]) & 0x0ff) << 8)  | (((int) data[i + 2]) & 0x0ff);                    buf.append(legalChars[(d >> 18) & 63]);                  buf.append(legalChars[(d >> 12) & 63]);                  buf.append(legalChars[(d >> 6) & 63]);                  buf.append(legalChars[d & 63]);                    i += 3;                    if (n++ >= 14) {                      n = 0;                      buf.append(" ");                  }              }                if (i == start + len - 2) {                  int d = ((((int) data[i]) & 0x0ff) << 16)   | ((((int) data[i + 1]) & 255) << 8);                    buf.append(legalChars[(d >> 18) & 63]);                  buf.append(legalChars[(d >> 12) & 63]);                  buf.append(legalChars[(d >> 6) & 63]);                  buf.append("=");              } else if (i == start + len - 1) {                  int d = (((int) data[i]) & 0x0ff) << 16;                    buf.append(legalChars[(d >> 18) & 63]);                  buf.append(legalChars[(d >> 12) & 63]);                  buf.append("==");              }                return buf.toString();          }            private static int decode(char c) {              if (c >= 'A' && c <= 'Z')                  return ((int) c) - 65;              else if (c >= 'a' && c <= 'z')                  return ((int) c) - 97 + 26;              else if (c >= '0' && c <= '9')                  return ((int) c) - 48 + 26 + 26;              else                  switch (c) {                  case '+':                      return 62;                  case '/':                      return 63;                  case '=':                      return 0;                  default:                      throw new RuntimeException("unexpected code: " + c);                  }          }            /**          * Decodes the given Base64 encoded String to a new byte array. The byte          * array holding the decoded data is returned.          */            public static byte[] decode(String s) {                ByteArrayOutputStream bos = new ByteArrayOutputStream();              try {                  decode(s, bos);              } catch (IOException e) {                  throw new RuntimeException();              }              byte[] decodedBytes = bos.toByteArray();              try {                  bos.close();                  bos = null;              } catch (IOException ex) {                  System.err.println("Error while decoding BASE64: " + ex.toString());              }              return decodedBytes;          }            private static void decode(String s, OutputStream os) throws IOException {              int i = 0;               int len = s.length();                while (true) {                  while (i < len && s.charAt(i) <= ' ')  i++;                    if (i == len)  break;                    int tri = (decode(s.charAt(i)) << 18)                          + (decode(s.charAt(i + 1)) << 12)                          + (decode(s.charAt(i + 2)) << 6)                          + (decode(s.charAt(i + 3)));                    os.write((tri >> 16) & 255);                  if (s.charAt(i + 2) == '=') break;                  os.write((tri >> 8) & 255);                  if (s.charAt(i + 3) == '=') break;                  os.write(tri & 255);                    i += 4;              }          }            }

2.DES base64 加密解密类：

package shared;import android.annotation.SuppressLint;import javax.crypto.Cipher;   import javax.crypto.spec.IvParameterSpec;   import javax.crypto.spec.SecretKeySpec;public class DES {       private static byte[] Key64 = { 10, 20, 30, 40, 50, 60, 70, 80 };    private static byte[] IV64 = { 100, 90, 80, 70, 60, 50, 40, 30 };        @SuppressLint("TrulyRandom")public static String encryptDES(String encryptString) throws Exception {              IvParameterSpec zeroIv = new IvParameterSpec(IV64);           SecretKeySpec key = new SecretKeySpec(Key64, "DES");           Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");           cipher.init(Cipher.ENCRYPT_MODE, key, zeroIv);           byte[] encryptedData = cipher.doFinal(encryptString.getBytes());                   return Base64.encode(encryptedData);       }          public static String decryptDES(String decryptString) throws Exception {   byte[] byteMi = Base64.decode(decryptString);           IvParameterSpec zeroIv = new IvParameterSpec(IV64);           SecretKeySpec key = new SecretKeySpec(Key64, "DES");           Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");           cipher.init(Cipher.DECRYPT_MODE, key, zeroIv);           byte decryptedData[] = cipher.doFinal(byteMi);                   return new String(decryptedData);       }     }

3. 应用：

    String result1 = DES.encryptDES("System.Data.EntityClient");      String result2 = DES.decryptDES("zULCxIQLwe4nl+3ZvGuWtmsD3KcVJqa0");

4. .net c# 写法：

using System;using System.Text;using System.Security.Cryptography;using System.IO;/// <summary>///对字符串进行加/解密/// </summary>public class Encryption{    private static byte[] Key64 = { 10, 20, 30, 40, 50, 60, 70, 80 };    private static byte[] IV64 = { 100, 90, 80, 70, 60, 50, 40, 30 };    /// <summary>    ///对字符串进行加密    /// </summary>    public static string EncryptString(string str)    {        byte[] b = Encoding.UTF8.GetBytes(str);        DESCryptoServiceProvider desp = new DESCryptoServiceProvider();        MemoryStream ms = new MemoryStream();        CryptoStream cs = new CryptoStream(ms, desp.CreateEncryptor(Key64, IV64), CryptoStreamMode.Write);        cs.Write(b, 0, b.Length);        cs.FlushFinalBlock();        cs.Close();        return Convert.ToBase64String(ms.ToArray());    }    /// <summary>    ///对字符串进行解密    /// </summary>    public static string DecryptString(string str)    {        byte[] b = Convert.FromBase64String(str);        DESCryptoServiceProvider desp = new DESCryptoServiceProvider();        MemoryStream ms = new MemoryStream();        CryptoStream cs = new CryptoStream(ms, desp.CreateDecryptor(Key64, IV64), CryptoStreamMode.Write);        cs.Write(b, 0, b.Length);        cs.FlushFinalBlock();        cs.Close();        return Encoding.UTF8.GetString(ms.ToArray());    }}

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