c# 数字ID与可见字符串码互转的一种实现

女爷i 2022-05-23 10:36 147阅读 0赞

# c\# 数字ID与可见字符串码互转的一种实现 #

适用场景：有时用户id等之类的字段用的是int类型，但在有些时候不想让这个id暴露，于是可以考虑把这个id转换成一个字符串，而且要可根据这个字符串得到相应的id值

实现如下代码：

using System;
    using System.Data;
    using System.Linq;
    using System.Security.Cryptography;
    using System.Text;
    
    namespace My.Common
    {
        /// <summary>
        /// 用户公共类
        /// </summary>
        public static class User
        {
           
            /// <summary>
            /// 加密对象
            /// </summary>
            private static readonly ICryptoTransform Encryptor;
            /// <summary>
            /// 解密对象
            /// </summary>
            private static readonly ICryptoTransform Decryptor;
    
            static User()
            {
                #region 加密解密初始化
    			//此处key要改成自己的
                const string key = "TEST2CDCA1CAEA1234D84FBDE3TEST22";
                var cryp = new TripleDESCryptoServiceProvider
                {
                    Key = Encoding.ASCII.GetBytes(key.Substring(0, 24)),
                    IV = Encoding.ASCII.GetBytes(key.Substring(24, 8)),
                    Mode = CipherMode.ECB,
                    Padding = PaddingMode.PKCS7
                };
    
                Encryptor = cryp.CreateEncryptor();
                Decryptor = cryp.CreateDecryptor();
                #endregion
            }
    
    
            }
    
            /// <summary>
            /// 获取用户CODE
            /// </summary>
            /// <returns></returns>
            public static string GetUserCodeV2(int userId)
            {
                var data = BitConverter.GetBytes(userId); //4个字节
                data = Encryptor.TransformFinalBlock(data, 0, data.Length);//加密后8个字节
                var bs = new byte[9];//避免BASE64后最后一位会为=
                bs[0] = (byte)(userId % 256);//生成一个字节 补满9个字节
                data.CopyTo(bs, 1);
                var strBase1 = Convert.ToBase64String(bs);
                //上面base64出来的字符串中可能会含有 "+" "/",再次base64会没有 
                return strBase1.Base64Encode();
            }
    
            /// <summary>
            /// 获取用户ID
            /// </summary>
            /// <returns></returns>
            public static int GetUserIdV2(string code)
            {
                try
                {
                    var baseCode = code.Base64Decode();
                    var bs = Convert.FromBase64String(baseCode);
                    return BitConverter.ToInt32(Decryptor.TransformFinalBlock(bs, 1, bs.Length - 1), 0);
                }
                catch
                {
                    return 0;
                }
            }
    
        }
    }

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