LdapHelper.cs

public static class LdapHelper { // https://www.codeproject.com/Articles/3688/How-to-get-user-SID-using-DirectoryServices-classe public static string ConvertByteToStringSid(byte[] sidBytes) { if (sidBytes == null || sidBytes.Length < 8 || sidBytes.Length > 68) // maximum 15 sub authorities return string.Empty; var span = new ReadOnlySpan<byte>(sidBytes); var strSid = new StringBuilder("S-"); // Add SID revision. strSid.Append(span[0]); // Get sub authority count... var subAuthoritiesLength = Convert.ToInt32(span[1]); if (sidBytes.Length != 8 + subAuthoritiesLength * 4) return string.Empty; long identifierAuthority = (((long)span[2]) << 40) + (((long)span[3]) << 32) + (((long)span[4]) << 24) + (((long)span[5]) << 16) + (((long)span[6]) << 8) + span[7]; strSid.Append('-'); strSid.Append(identifierAuthority); span = span[8..]; for (int i = 0; i < subAuthoritiesLength; i++, span = span[4..]) { strSid.Append('-'); strSid.Append(BitConverter.ToUInt32(span.Slice(0, 4))); } return strSid.ToString(); } }