Decoding a gMSA Password Blob

  //https://msdn.microsoft.com/en-us/library/hh881234.aspx

    public class msDSManagedPassword

    {

        public short Version

        {

            get;

            set;

        }

        public string CurrentPassword

        {

            get;

            set;

        }

        public string OldPassword

        {

            get;

            set;

        }

        public DateTime dtNextQueryTime

        {

            get;

            set;

        }

        public DateTime dtPwdGoodUntil

        {

            get;

            set;

        }

        //https://msdn.microsoft.com/en-us/library/hh881234.aspx

        public msDSManagedPassword(byte[] blob)

        {

            using (Stream stream = new MemoryStream(blob))

            {

                using (BinaryReader reader = new BinaryReader(stream))

                {

                    this.Version = reader.ReadInt16();

                    short reserved = reader.ReadInt16();

                    //size of blob

                    int length = reader.ReadInt32();

                    if (length != blob.Length)

                    {

                        throw new Exception("Blob is malsized");

                    }

                    short curPwdOffset = reader.ReadInt16();

                    this.CurrentPassword = getUnicodeString(blob, curPwdOffset);

                    short oldPwdOffset = reader.ReadInt16();

                    if (oldPwdOffset > 0)

                    {

                        this.OldPassword = getUnicodeString(blob, oldPwdOffset);

                    }

                    short queryPasswordIntervalOffset = reader.ReadInt16();

                    long queryPasswordIntervalTicks = BitConverter.ToInt64(blob, queryPasswordIntervalOffset);

                    this.dtNextQueryTime = DateTime.UtcNow + TimeSpan.FromTicks(queryPasswordIntervalTicks);

                    short unchangedPasswordIntervalOffset = reader.ReadInt16();

                    long unchangedPasswordIntervalTicks = BitConverter.ToInt64(blob, unchangedPasswordIntervalOffset);

                    this.dtPwdGoodUntil = DateTime.UtcNow + TimeSpan.FromTicks(unchangedPasswordIntervalTicks);

                }

            }

        }

        public static string getUnicodeString(byte[] blob, int index)

        {

            string stOut = "";

            for (int i = index; i < blob.Length; i += 2)

            {

                char ch = BitConverter.ToChar(blob, i);

                if (ch == Char.MinValue)

                {

                    //found the end  .    A null-terminated WCHAR string

                    return stOut;

                }

                stOut = stOut + ch;

            }

            return null;

        }

    }