C# 擷取檔案MD5、SHA1

/// <summary> /// 計算檔案的 MD5 值 /// </summary> /// <param name="fileName">要計算 MD5 值的檔案名稱和路徑</param> /// <returns>MD5 值16進位字串</returns> public string MD5File(string fileName) { return HashFile(fileName, "md5"); } /// <summary> /// 計算檔案的 sha1 值 /// </summary> /// <param name="fileName">要計算 sha1 值的檔案名稱和路徑</param> /// <returns>sha1 值16進位字串</returns> public string SHA1File(string fileName) { return HashFile(fileName, "sha1"); } /// <summary> /// 計算檔案的雜湊值 /// </summary> /// <param name="fileName">要計算雜湊值的檔案名稱和路徑</param> /// <param name="algName">演算法:sha1,md5</param> /// <returns>雜湊值16進位字串</returns> private string HashFile(string fileName, string algName) { if (!System.IO.File.Exists(fileName)) return string.Empty; System.IO.FileStream fs = new System.IO.FileStream(fileName, System.IO.FileMode.Open, System.IO.FileAccess.Read); byte[] hashBytes = HashData(fs, algName); fs.Close(); return ByteArrayToHexString(hashBytes); } /// <summary> /// 計算雜湊值 /// </summary> /// <param name="stream">要計算雜湊值的 Stream</param> /// <param name="algName">演算法:sha1,md5</param> /// <returns>雜湊值位元組數組</returns> private byte[] HashData(System.IO.Stream stream, string algName) { System.Security.Cryptography.HashAlgorithm algorithm; if (algName == null) { throw new ArgumentNullException("algName 不能為 null"); } if (string.Compare(algName, "sha1", true) == 0) { algorithm = System.Security.Cryptography.SHA1.Create(); } else { if (string.Compare(algName, "md5", true) != 0) { throw new Exception("algName 只能使用 sha1 或 md5"); } algorithm = System.Security.Cryptography.MD5.Create(); } return algorithm.ComputeHash(stream); } /// <summary> /// 位元組數群組轉換為16進位表示的字串 /// </summary> private string ByteArrayToHexString(byte[] buf) { return BitConverter.ToString(buf).Replace("-",""); }