一个简单字符串加密解密类，请问如何调用？

大家好 这是一个简单的字符串加密和解密类 请问我在cs文件里面如何调用呢 ？希望能说详细点，新手啊 哈
1using System;
 2using System.Text;
 3using System.Security.Cryptography;
 4using System.IO;
 5
 6 
 7
 8//默认密钥向量
 9private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
10/**//**//**//// <summary>
11/// DES加密字符串
12/// </summary>
13/// <param name="encryptString">待加密的字符串</param>
14/// <param name="encryptKey">加密密钥,要求为8位</param>
15/// <returns>加密成功返回加密后的字符串，失败返回源串</returns>
16public static string EncryptDES(string encryptString, string encryptKey)
17{
18    try
19    {
20        byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
21        byte[] rgbIV = Keys;
22        byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
23        DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
24        MemoryStream mStream = new MemoryStream();
25        CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
26        cStream.Write(inputByteArray, 0, inputByteArray.Length);
27        cStream.FlushFinalBlock();
28        return Convert.ToBase64String(mStream.ToArray());
29    }
30    catch
31    {
32        return encryptString;
33    }
34}
35
36/**//**//**//// <summary>
37/// DES解密字符串
38/// </summary>
39/// <param name="decryptString">待解密的字符串</param>
40/// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>
41/// <returns>解密成功返回解密后的字符串，失败返源串</returns>
42public static string DecryptDES(string decryptString, string decryptKey)
43{
44    try
45    {
46        byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
47        byte[] rgbIV = Keys;
48        byte[] inputByteArray = Convert.FromBase64String(decryptString);
49        DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
50        MemoryStream mStream = new MemoryStream();
51        CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
52        cStream.Write(inputByteArray, 0, inputByteArray.Length);
53        cStream.FlushFinalBlock();
54        return Encoding.UTF8.GetString(mStream.ToArray());
55    }
56    catch
57    {
58        return decryptString;
59    }
60}
61