How do I make this go faster? It currently takes about 30 seconds on a 3gb file. I am using this to get a checksum from the file to compare it to Microsoft's official checksums. I am wondering if using a buffer would help and if so how should I do that?public static String GetSHA1Hash(string fileName)            {                string strResult = String.Empty;                string strHashData = String.Empty;                byte[] arrbytHashValue;                System.IO.FileStream oFileStream = null;                System.Security.Cryptography.SHA1CryptoServiceProvider oSHAHasher =                    new System.Security.Cryptography.SHA1CryptoServiceProvider();                try                {                    oFileStream = GetFileStream(fileName);                    arrbytHashValue = oSHAHasher.ComputeHash(oFileStream);                    oFileStream.Close();                    strHashData = BitConverter.ToString(arrbytHashValue);                    strHashData = strHashData.Replace(-, String.Empty);                    strResult = strHashData;                }                catch (Exception ex) { return ex.Message; }                finally { ((IDisposable)oSHAHasher).Dispose(); }                return (strResult);            }
SHA1 Hash Checker
c#