The rights to develop and release protocols are held by Microsoft, but all technical details are free for access and implementation.
[5] Microsoft developed a proprietary extension to the Kerberos network authentication protocol for the Windows 2000 operating system.
The extensions made the protocol incompatible with implementations supporting the original standards, and this has raised concerns that this, along with the licensing restrictions, effectively denies products unable to conform to the standard access to a Windows 2000 Server using Kerberos.
[7] Reverse engineering is the process of retrieving a protocol’s details from a software implementation of the specification.
Methods of reverse-engineering a protocol include packet sniffing and binary decompilation and disassembly.