签名工具类

要求

1. 首先，排除sign参数之外，将其它参数（空值除外）按名称进行字母排序，并和它的取值一起组成name=value样式的字符串，然后用&把它们拼装为一个大字符串，对于嵌套的参数，嵌套的参数列表也需按照字母排序进行拼装。
   a) 比如，要传递下列参数
   i.version=1.0.0
   ii.return_code=0
   iii.拼装之后的字符串为：return_code=0&version=1.0.0
   b) 比如，要传递下列参数
   i.a=1
   ii.b={“d”:”3”,”c”:”2”}
   iii.拼装之后的字符串为：a=1&b=c=2&d=3
   c)比如，要传递下列参数
   i.a=1
   ii.b=[{“d”:”3”,”c”:”2”},{“d”:”5”,”c”:”4”}]
   iii.拼装之后的字符串为：a=1&b=c=2&d=3&c=4&d=5
   d)比如，要传递下列参数
   i.a=1
   ii.b=[“2”,”3”]
   iii.拼装之后的字符串为：a=1&b=2&3
   e)比如，要传递下列参数
   i.a=1
   ii.b=[[{“d1”:”1”,”c1”:”2”},{“d2”:”3”,”c2”:”4”}],[{“d3”:”5”,”c3”:”6”},{“d4”:”7”,”c4”:”8”}]]
   iii.拼装之后的字符串为：a=1&b=c1=2&d1=1&c2=4&d2=3&c3=6&d3=5&c4=8&d4=7
2. 在上述拼装之后的字符串后面直接拼装accesskey的值。
   a)比如，上述参数return_code=0&version=1.0.0，假设accesskey是123456789ABCDEF，拼装以后，成为下述字符串：
   b)return_code=0&version=1.0.0123456789ABCDEF
3. 对上述第2步得到的字符串，进行MD5运算（32位大写），得到sign

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.Security.Cryptography;
using System.Text;
namespace Demo
{
    public class SignUtils
    {
        private static readonly JsonSerializerSettings jSetting = new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore, DefaultValueHandling = DefaultValueHandling.Include };
        public static string GetToBeSign(SortedDictionary<string, object> dictionary)
        {
            var json = JsonConvert.SerializeObject(dictionary, jSetting);
            var jobj = JsonConvert.DeserializeObject<JObject>(json);
            return GetToBeSign(jobj);
        }
        public static string GetToBeSign(string json)
        {
            var jobj = JsonConvert.DeserializeObject<JObject>(json);
            return GetToBeSign(jobj);
        }
        public static string GetToBeSign(JObject jobj)
        {
            var _dictionary = new SortedDictionary<string, string>();
            foreach (var item in jobj)
            {
                if (item.Value == null || "".Equals(item.Value) || "".Equals(item.Value.ToString()) || "sign".Equals(item.Key) || "mac".Equals(item.Key))
                {
                    continue;
                }
                var value = item.Value.ToString();
                if (item.Value.GetType() == typeof(JObject))
                {
                    value = GetToBeSign(value);
                }
                else if (item.Value.GetType() == typeof(JArray))
                {
                    value = GetJsonArrayStr(value);
                }
                _dictionary.Add(item.Key, value);
            }
            var values = _dictionary.OrderBy(o => o.Key)
                .Select(s => $"{s.Key}={s.Value}");
            return string.Join("&", values);
        }
        public static string GetJsonArrayStr(string jarrstr)
        {
            var jarr = JsonConvert.DeserializeObject<JArray>(jarrstr);
            return GetJsonArrayStr(jarr);
        }
        public static string GetJsonArrayStr(JArray jarr)
        {
            var values = new List<string>();
            foreach (var item in jarr)
            {
                var value = item.ToString();
                if (item.GetType() == typeof(JObject))
                {
                    value = GetToBeSign(item.ToString());
                }
                else if (item.GetType() == typeof(JArray))
                {
                    value = GetJsonArrayStr(item as JArray);
                }
                values.Add(value);
            }
            return string.Join("&", values);
        }
        /// <summary>
        /// 使用 MD5 对输入字符串进行加密
        /// </summary>
        /// <param name="inputString">需要加密的字符串</param>
        /// <param name="charset">编码格式</param>
        /// <returns>返回加密后的字符串</returns>
        private static string ConvertToMD5(string inputString, string charset = null)
        {
            if (string.IsNullOrEmpty(charset))
            {
                charset = "utf-8";
            }
            MD5 md5Hash = MD5.Create();
            byte[] bytes = md5Hash.ComputeHash(Encoding.GetEncoding(charset).GetBytes(inputString));
            StringBuilder result = new StringBuilder();
            foreach (byte b in bytes)
            {
                result.Append(b.ToString("x2"));
            }
            return result.ToString();
        }
        public static string Sign(string json, string key)
        {
            var tobesign = $"{GetToBeSign(json)}{key}";
            var sign = ConvertToMD5(tobesign).ToUpper();
            return sign;
        }
        public static string Sign(SortedDictionary<string, object> dictionary, string key)
        {
            var tobesign = $"{GetToBeSign(dictionary)}{key}";
            var sign = ConvertToMD5(tobesign).ToUpper();
            return sign;
        }
        public static bool CheckSign(string json, string key)
        {
            var param = JsonConvert.DeserializeObject<Dictionary<string, object>>(json);
            var ispassed = param.TryGetValue("sign", out object originsign);
            if (!ispassed) { return !ispassed; }
            var tobesign = $"{GetToBeSign(json)}{key}";
            var sign = ConvertToMD5(tobesign).ToUpper();
            return originsign.ToString() == sign;
        }
    }
}