let phpMd5 (dataToHash:string) = use md5 = new System.Security.Cryptography.MD5CryptoServiceProvider(); let encodedBytes = dataToHash |> System.Text.ASCIIEncoding.Default.GetBytes |> md5.ComputeHash System.Text.RegularExpressions.Regex.Replace( System.BitConverter.ToString(encodedBytes), "-", "").ToLower()