C#下的兩種加密方式MD5和DEC

md5加密

/// <summary>
    /// MD5加密
    /// </summary>
    /// <param name="toCryString">要加密的字符串</param>
    /// <returns></returns>
    public static string GetMD5Str(string toCryString)
    {
        MD5CryptoServiceProvider hashmd5;
        hashmd5 = new MD5CryptoServiceProvider();
        return BitConverter.ToString(hashmd5.ComputeHash(Encoding.Default.GetBytes(toCryString))).Replace("-", "").ToLower();//asp是小寫,把所有字符變小寫
    }

 

DES加密解密

///
/// DEC 加密過程
///
public static string Encrypt(string pToEncrypt, string sKey)
{
DESCryptoServiceProviderdes = new DESCryptoServiceProvider();　//把字符串放到byte數組中

byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
//byte[]　inputByteArray=Encoding.Unicode.GetBytes(pToEncrypt);

des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);　//建立加密對象的密鑰和偏移量
des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);　 //原文使用ASCIIEncoding.ASCII方法的GetBytes方法
MemoryStream ms = new MemoryStream();　　 //使得輸入密碼必須輸入英文文本
CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);

cs.Write(inputByteArray, 0, inputByteArray.Length);
cs.FlushFinalBlock();

StringBuilder ret = new StringBuilder();
foreach (byte b in ms.ToArray())
{
ret.AppendFormat("{0:X2}", b);
}
ret.ToString();
return ret.ToString();
}

///
/// DEC 解密過程
///
public static string Decrypt(string pToDecrypt, string sKey)
{
DESCryptoServiceProviderdes = new DESCryptoServiceProvider();

byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
for (int x = 0; x < pToDecrypt.Length / 2; x++)
{
int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
inputByteArray[x] = (byte)i;
}

des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);　//建立加密對象的密鑰和偏移量，此值重要，不能修改
des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);

cs.Write(inputByteArray, 0, inputByteArray.Length);
cs.FlushFinalBlock();

StringBuilder ret = new StringBuilder();　//建立StringBuild對象，CreateDecrypt使用的是流對象，必須把解密后的文本變成流對象

return System.Text.Encoding.Default.GetString(ms.ToArray());
}

其中的sKey非常重要,定義的時候定義成string然后賦值等於八個字母或數字,注意,必須8個
這個也很實用,譬如你想進入文章頁面,傳入的參數的aid=10000
這時把10000給加密
然后接受的時候解密.這樣能有效的防止sql注入攻擊!