In telecommunications, a proprietary protocol is a communications protocol

Communications protocol

A communications protocol is a system of digital message formats and rules for exchanging those messages in or between computing systems and in telecommunications...

 owned by a single organization or individual.

Enforcement

Proprietors may enforce restrictions through patent

Patent

A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....

s and by keeping the protocol specification a trade secret

Trade secret

A trade secret is a formula, practice, process, design, instrument, pattern, or compilation of information which is not generally known or reasonably ascertainable, by which a business can obtain an economic advantage over competitors or customers...

. These restrictions are intended to give the owner control of the protocol.

Examples

The Skype protocol

Skype Protocol

The Skype protocol is a proprietary Internet telephony network based on peer-to-peer architecture, used by Skype. The protocol's specifications have not been made publicly available by Skype and official applications using the protocol are closed-source....

 is a proprietary protocol.

The Venturi Transport Protocol

Venturi Transport Protocol

Venturi Transport Protocol is a patented proprietary transport layer protocol that is designed to transparently replace TCP in order to overcome inefficiencies in the design of TCP related to wireless data transport...

 (VTP) is a patented proprietary protocol that is designed to replace TCP

Transmission Control Protocol

The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol , and therefore the entire suite is commonly referred to as TCP/IP...

 transparently in order to overcome perceived inefficiencies related to wireless data transport.

Microsoft

Microsoft

Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

 Exchange Server protocols are proprietary open access protocols. The rights to develop and release protocols are held by Microsoft, but all technical details are free for access and implementation.

Effects of incompatibility

The use of proprietary instant messaging

Instant messaging

Instant Messaging is a form of real-time direct text-based chatting communication in push mode between two or more people using personal computers or other devices, along with shared clients. The user's text is conveyed over a network, such as the Internet...

 protocols meant that instant messaging networks were incompatible and people were unable to reach friends on other networks. This cost the instant messaging format dearly.

Proprietary extensions to open protocols

Microsoft

Microsoft

Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

 developed a proprietary extension to the Kerberos network authentication protocol for the Windows 2000

Windows 2000

Windows 2000 is a line of operating systems produced by Microsoft for use on personal computers, business desktops, laptops, and servers. Windows 2000 was released to manufacturing on 15 December 1999 and launched to retail on 17 February 2000. It is the successor to Windows NT 4.0, and is the...

 operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

. The extensions made the protocol incompatible with implementations supporting the original standard, 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.

Reverse engineering

Reverse engineering is the process of retrieving a protocol’s details from a software

Computer software

Computer software, or just software, is a collection of computer programs and related data that provide the instructions for telling a computer what to do and how to do it....

 implementation of the specification. Methods of reverse-engineering a protocol include packet sniffing and binary decompilation and disassembly.

There are legal precedents when the reverse-engineering is aimed at interoperability of protocols. In the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, the Digital Millennium Copyright Act

Digital Millennium Copyright Act

The Digital Millennium Copyright Act is a United States copyright law that implements two 1996 treaties of the World Intellectual Property Organization . It criminalizes production and dissemination of technology, devices, or services intended to circumvent measures that control access to...

 grants a safe harbor to reverse engineer software for the purposes of interoperability

Interoperability

Interoperability is a property referring to the ability of diverse systems and organizations to work together . The term is often used in a technical systems engineering sense, or alternatively in a broad sense, taking into account social, political, and organizational factors that impact system to...

with other software.