rg1/server/ServerComm/Comm/HashHelper.cs

using Google.Protobuf.WellKnownTypes;
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace Sog
{
    /// <summary>
    /// Hash辅助类
    /// </summary>
    public class HashHelper
    {
        //注意：这个算法不允许修改！！，改了会导致运营的项目的悲剧
        // 自己实现字符串的hash算法，不用C#缺省的string.HashCode(),方便其他程序和工具计算结果一致
        //这个算法来自Brian Kernighan 和 Dennis Ritchie的 The C Programming Language。
        //这是一个很简单的哈希算法,使用了一系列奇怪的数字,形式如31,3131,31...31,看上去和DJB算法很相似。(这个就是Java的字符串哈希函数)
        //c#内部用的应该和这个类似
        public static int HashStringForIndex(string str)
        {
            const int seed = 131;

            int hash = 0;

            for (int i = 0; i < str.Length; i++)
            {
                hash = hash * seed + str[i];
            }

            //保证正数
            return hash & 0x7FFFFFFF;
        }

        public static string MD5Bytes(byte[] data)
        {
            return HashBytes(data, "md5");
        }

        public static string MD5Utf8String(string str)
        {
            var md5 = MD5.Create();
            byte[] strbyte = Encoding.UTF8.GetBytes(str);
            byte[] md5Hash = md5.ComputeHash(strbyte);
            string md5Str = BitConverter.ToString(md5Hash).Replace("-", "").ToLower();
            return md5Str;
        }

        /// <summary>
        /// 计算文件的 MD5 值
        /// </summary>
        /// <param name="fileName">要计算 MD5 值的文件名和路径</param>
        /// <returns>MD5 值16进制字符串</returns>
        public static string MD5String(string str)
        {
            return HashString(str, "md5");
        }

        /// <summary>
        /// 计算文件的 sha1 值
        /// </summary>
        /// <param name="str">string</param>
        /// <returns>sha1 值16进制字符串</returns>
        public static string SHA1String(string str)
        {
            return HashString(str, "sha1");
        }

        /// <summary>
        /// 计算文件的 MD5 值
        /// </summary>
        /// <param name="fileName">要计算 MD5 值的文件名和路径</param>
        /// <returns>MD5 值16进制字符串</returns>
        public static string MD5File(string fileName)
        {
            return HashFile(fileName, "md5");
        }

        /// <summary>
        /// 计算文件的 sha1 值
        /// </summary>
        /// <param name="fileName">要计算 sha1 值的文件名和路径</param>
        /// <returns>sha1 值16进制字符串</returns>
        public static string SHA1File(string fileName)
        {
            return HashFile(fileName, "sha1");
        }

        /// <summary>
        /// 计算文件的哈希值
        /// </summary>
        /// <param name="str">string</param>
        /// <param name="algName">算法:sha1,md5</param>
        /// <returns>哈希值16进制字符串</returns>
        private static string HashString(string str, string algName)
        {
            if (str == null || algName == null)
            {
                return string.Empty;
            }

            byte[] array = Encoding.UTF8.GetBytes(str);
            using (MemoryStream stream = new MemoryStream(array))
            {
                byte[] hashBytes = HashData(stream, algName);
                if (hashBytes != null)
                {
                    return ByteArrayToHexString(hashBytes);
                }
            }

            return string.Empty;
        }


        /// <summary>
        /// 计算文件的哈希值
        /// </summary>
        /// <param name="fileName">要计算哈希值的文件名和路径</param>
        /// <param name="algName">算法:sha1,md5</param>
        /// <returns>哈希值16进制字符串</returns>
        private static string HashFile(string fileName, string algName)
        {
            if (! File.Exists(fileName))
            {
                return string.Empty;
            }

            FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
            byte[] hashBytes = HashData(fs, algName);
            fs.Close();

            if (hashBytes != null)
            {
                return ByteArrayToHexString(hashBytes);
            }

            return string.Empty;
        }

        private static HashAlgorithm CreateHashAlgorithm(string algName)
        {
            HashAlgorithm algorithm = null;

            if (string.Compare(algName, "sha1", true) == 0)
            {
                algorithm = SHA1.Create();
            }
            else if (string.Compare(algName, "md5", true) == 0)
            {
                algorithm = MD5.Create();
            }

            return algorithm;
        }

        /// <summary>
        /// 计算哈希值
        /// </summary>
        /// <param name="stream">要计算哈希值的 Stream</param>
        /// <param name="algName">算法:sha1,md5</param>
        /// <returns>哈希值字节数组</returns>
        private static byte[] HashData(Stream stream, string algName)
        {
            if (algName == null)
            {
                return null;
            }

            var algorithm = CreateHashAlgorithm(algName);
            if (algorithm == null)
            {
                return null;
            }

            try
            {
                return algorithm.ComputeHash(stream);
            }
            catch
            {
                algorithm.Dispose();
                return null;
            }
        }

        private static string HashBytes(byte[] data, string algName)
        {
            if (data == null || algName == null)
            {
                return string.Empty;
            }

            var algorithm = CreateHashAlgorithm(algName);
            if (algorithm == null)
            {
                return string.Empty;
            }

            try
            {
                byte[] hashData = algorithm.ComputeHash(data);
                return ByteArrayToHexString(hashData);
            }
            catch
            {
                algorithm.Dispose();
            }

            return string.Empty;
        }

        /// <summary>
        /// 字节数组转换为16进制表示的字符串
        /// </summary>
        private static string ByteArrayToHexString(byte[] buf)
        {
            // stackoverflow有帖子提到BitConverter有的版本会用"-"把bytes分组
            return BitConverter.ToString(buf).Replace("-", "").ToLower();
        }

        /// <summary>
        /// 获取HMACSHA256 加密字符串 16位编码
        /// </summary>
        /// <param name="key"></param>
        /// <param name="mesg"></param>
        /// <returns></returns>
        public static string GetHMACSHA256(string key, string mesg)
        {
            StringBuilder hex = new StringBuilder();
            // 使用UTF-8编码将字符串转换为字节数组
            byte[] keyByte = Encoding.UTF8.GetBytes(key);
            byte[] messageBytes = Encoding.UTF8.GetBytes(mesg);
            // 创建一个新的HMACSHA256实例，使用appKey作为密钥
            using (HMACSHA256 hmac = new HMACSHA256(keyByte))
            {
                byte[] hashMessage = hmac.ComputeHash(messageBytes);
                foreach (byte b in hashMessage)
                {
                    hex.AppendFormat("{0:x2}", b);
                }
            }
            return hex.ToString();
        }
    }
}