C# 数据库链接字符串加密解密工具代码详解

<add key="ConfigString" value="4HsXBRNXTkeN0ZoKdEwFE501TKSqLZUyJ0Zf+C7s5+gPd1SbWBiuh4PG6jeFgcnCTFr0QFW8FN40m/S8xmQq+8srL8taMLO23z6GSmaQJoM="/>

public class ConfigInformation
 {
  private static ConfigInformation _configInformation;
  public ConfigInformation Instance
  {
   get
   {
    if (_configInformation == null)
    {
     _configInformation = new ConfigInformation();
    }
    return _configInformation;
   }
  }
  // 数据库链接字符串加解密 Key Value
  public static String Key = "27e167e9-2660-4bc1-bea0-c8781a9f01cb";
  public static String Vector = "8280d587-f9bf-4127-bbfa-5e0b4b672958";
 }

/// <summary>
 /// 加密 解密
 /// </summary>
 public class DecryptAndEncryptionHelper
 {
  private readonly SymmetricAlgorithm _symmetricAlgorithm;
  private const String DefKey = "qazwsxedcrfvtgb!@#$%^&*(tgbrfvedcwsxqaz)(*&^%$#@!";
  private String _key = "";
  public String Key
  {
   get { return _key; }
   set
   {
    if (!String.IsNullOrEmpty(value))
    {
     _key = value;
    }
    else
    {
     _key = DefKey;
    }
   }
  }
  private const String DefIV = "tgbrfvedcwsxqaz)(*&^%$#@!qazwsxedcrfvtgb!@#$%^&*(";
  private String _iv = "";
  public String IV
  {
   get { return _iv; }
   set
   {
    if (!String.IsNullOrEmpty(value))
    {
     _iv = value;
    }
    else
    {
     _iv = DefIV;
    }
   }
  }
  public DecryptAndEncryptionHelper()
  {
   _symmetricAlgorithm = new RijndaelManaged();
  }
  public DecryptAndEncryptionHelper(String Key, String IV)
  {
   _symmetricAlgorithm = new RijndaelManaged();
   _key = String.IsNullOrEmpty(Key) ? DefKey : Key;
   _iv = String.IsNullOrEmpty(IV) ? DefIV : IV;
  }
  /// <summary>
  /// Get Key
  /// </summary>
  /// <returns>密钥</returns>
  private byte[] GetLegalKey()
  {
   _symmetricAlgorithm.GenerateKey();
   byte[] bytTemp = _symmetricAlgorithm.Key;
   int KeyLength = bytTemp.Length;
   if (_key.Length > KeyLength)
    _key = _key.Substring(0, KeyLength);
   else if (_key.Length < KeyLength)
    _key = _key.PadRight(KeyLength, '#');
   return ASCIIEncoding.ASCII.GetBytes(_key);
  }
  /// <summary>
  /// Get IV
  /// </summary>
  private byte[] GetLegalIV()
  {
   _symmetricAlgorithm.GenerateIV();
   byte[] bytTemp = _symmetricAlgorithm.IV;
   int IVLength = bytTemp.Length;
   if (_iv.Length > IVLength)
    _iv = _iv.Substring(0, IVLength);
   else if (_iv.Length < IVLength)
    _iv = _iv.PadRight(IVLength, '#');
   return ASCIIEncoding.ASCII.GetBytes(_iv);
  }
  /// <summary>
  /// Encrypto 加密
  /// </summary>
  public string Encrypto(string Source)
  {
   byte[] bytIn = UTF8Encoding.UTF8.GetBytes(Source);
   MemoryStream ms = new MemoryStream();
   _symmetricAlgorithm.Key = GetLegalKey();
   _symmetricAlgorithm.IV = GetLegalIV();
   ICryptoTransform encrypto = _symmetricAlgorithm.CreateEncryptor();
   CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write);
   cs.Write(bytIn, 0, bytIn.Length);
   cs.FlushFinalBlock();
   ms.Close();
   byte[] bytOut = ms.ToArray();
   return Convert.ToBase64String(bytOut);
  }
  /// <summary>
  /// Decrypto 解密
  /// </summary>
  public string Decrypto(string Source)
  {
   byte[] bytIn = Convert.FromBase64String(Source);
   MemoryStream ms = new MemoryStream(bytIn, 0, bytIn.Length);
   _symmetricAlgorithm.Key = GetLegalKey();
   _symmetricAlgorithm.IV = GetLegalIV();
   ICryptoTransform encrypto = _symmetricAlgorithm.CreateDecryptor();
   CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read);
   StreamReader sr = new StreamReader(cs);
   return sr.ReadToEnd();
  }
 }

// 获取加密的链接字符串，然后解密
string enString = ConfigurationManager.AppSettings["ConfigString"];
DecryptAndEncryptionHelper helper = new DecryptAndEncryptionHelper(ConfigInformation.Key, ConfigInformation.Vector);
// 明文
var configStr = helper.Decrypto(enString); 
return configStr;