C#中DES加密解密
加密和解密是一门高深和复杂的学科。在程序中有时需要用一些简单的加密和解密，以保证一些关键字符串、值等地安全性。这里就要用到DES加密解密。当然我们不用深究这些加密的原理了，因为如果深究的话估计都得转行研究数学。DES加密解密C#中需要用到这几个类，DESCryptoServiceProvider，CryptoStream。
看下面的两组加密解密代码。
1、
（1）、对字符串进行DES加密
public static string Encrypt(string sourceString, string key, string iv) { try { byte[] btKey = Encoding.UTF8.GetBytes(key); byte[] btIV = Encoding.UTF8.GetBytes(iv); DESCryptoServiceProvider des = new DESCryptoServiceProvider(); using (MemoryStream ms = new MemoryStream()) { byte[] inData = Encoding.UTF8.GetBytes(sourceString); try { using (CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(btKey, btIV), CryptoStreamMode.Write)) { cs.Write(inData, 0, inData.Length); cs.FlushFinalBlock(); } return Convert.ToBase64String(ms.ToArray()); } catch { return sourceString; } } } catch { } return "DES加密出错"; } 调用： string recordString = Encrypt("金胖子死了", "20111219", "12345678"); 结果：recordString= "xQ969nexy964SXhkTuekUQ=="
（2）、 对DES加密后的字符串进行解密
public static string Decrypt(string encryptedString, string key, string iv) { byte[] btKey = Encoding.UTF8.GetBytes(key); byte[] btIV = Encoding.UTF8.GetBytes(iv); DESCryptoServiceProvider des = new DESCryptoServiceProvider(); using (MemoryStream ms = new MemoryStream()) { byte[] inData = Convert.FromBase64String(encryptedString); try { using (CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(btKey, btIV), CryptoStreamMode.Write)) { cs.Write(inData, 0, inData.Length); cs.FlushFinalBlock(); } return Encoding.UTF8.GetString(ms.ToArray()); } catch { return encryptedString; } } } 调用：string recordString = DESOperation.Decrypt("xQ969nexy964SXhkTuekUQ==", "20111219", "12345678"); 结果：recordString = “金胖子死了”;
2、
（1）、加密字符串
public static string EncryptString(string sInputString, string sKey, string sIV) { try { byte[] data = Encoding.UTF8.GetBytes(sInputString); DESCryptoServiceProvider DES = new DESCryptoServiceProvider(); DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey); DES.IV = ASCIIEncoding.ASCII.GetBytes(sIV); ICryptoTransform desencrypt = DES.CreateEncryptor(); byte[] result = desencrypt.TransformFinalBlock(data, 0, data.Length); return BitConverter.ToString(result); } catch { } return "转换出错！"; } 调用：string recordString = DESOperation.EncryptString("金胖子死了", "20111219", "12345678"); 结果：recordString = "C5-0F-7A-F6-77-B1-CB-DE-B8-49-78-64-4E-E7-A4-51";
（2）、解密字符串
public static string DecryptString(string sInputString, string sKey, string sIV) { try { string[] sInput = sInputString.Split("-".ToCharArray()); byte[] data = new byte[sInput.Length]; for (int i = 0; i < sInput.Length; i++) { data[i] = byte.Parse(sInput[i], NumberStyles.HexNumber); } DESCryptoServiceProvider DES = new DESCryptoServiceProvider(); DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey); DES.IV = ASCIIEncoding.ASCII.GetBytes(sIV); ICryptoTransform desencrypt = DES.CreateDecryptor(); byte[] result = desencrypt.TransformFinalBlock(data, 0, data.Length); return Encoding.UTF8.GetString(result); } catch { } return "解密出错！"; } 调用：string recordString = DESOperation.DecryptString("C5-0F-7A-F6-77-B1-CB-DE-B8-49-78-64-4E-E7-A4-51", "20111219", "12345678"); 结果：recordString =” 金胖子死了”;
注意：密钥和向量必须为8位，否则加密解密都不成功。