Frequently Asked Questions

Responses to common questions about the CATALINK Initiative


The CATALINK project builds an open source, additive, multilateral crisis communication technology for use by the leaders of nuclear weapons states. If implemented, CATALINK would build on the “hotline” model of previous generations, and rely on internationally-driven open-source technologies to maximize user integrity and trust. A full brief on CATALINK and additional information on CATALINK can be found at

What are the CATALINK Components?

The Puck 

A simple, secure, and robust device meant for dedicated communication between global leaders and officials during a nuclear crisis or other high-stakes events like disaster response. Designed with an open-source platform, the Puck will send text messages in minutes.

The Broker  

An interface between the puck and the ROCCS which determines the path of the Puck message throughout the desired network.

The ROCCS (Resilient Omni Frequency Crisis Communications System)

A permanently active global mesh network, the ROCCS uses multiple channels/wavelengths to ensure reliable message relays; one of a variety of redundant networks for puck messages to use depending on availability, the threat environment, and the type of message sent.

Why is CATALINK needed?

Not every country with nuclear weapons has a direct leader or military communication line with every other country with nuclear weapons. Additionally, there are no multilateral hotlines between states with nuclear weapons. Unlike the Cold War when security concerns were largely focused on one bilateral conflictual dyad, 21st century challenges are increasingly complex with multiple strategic competitors. CATALINK is an additive measure, not meant to replace existing hotlines but to add other resilient options for leaders to communicate before, during, and after a conflict or nuclear war. 

Existing hotlines may be vulnerable to kinetic threats, such as environmental degradation or destruction during conflict, or non-kinetic threats such as cyber attacks and electronic warfare. New technological developments that could further destabilize communications (e.g. AI-generated audio and video) must also now be taken into account when thinking of how to improve resiliency, especially in a degraded security environment where miscommunication and misperceptions can flourish.

What is the Institute for Security and Technology and what do they have to do with CATALINK?

IST, a 501(c)(3) nonprofit organization, houses the CATALINK initiative. As new technologies present humanity with unprecedented capabilities, they can also pose unimagined risks to global security. The Institute for Security and Technology’s (IST) mission is to bridge gaps between technology and policy leaders to help solve these emerging security problems together. Uniquely situated on the West Coast with deep ties to Washington, D.C., we have the access and relationships to unite the best experts, at the right time, using the most powerful mechanisms. 

CATALINK was conceived during international meetings convened by IST at Stanford University’s Hoover Institute in 2019, where IST brought together global nuclear policymakers, academics, current and former senior decisionmakers, and experts from the technology sector for discussions on global nuclear communications.

Is this an American project?

Although the Institute for Security and Technology is based in the United States, it is actively engaging the international community throughout the development of CATALINK. Likewise, because nuclear war is a global threat, IST is committed to ensuring that all experts, engineers, scientists, diplomats, and other individuals involved in CATALINK reflect the international community. Looking for examples of how to build international consensus around this concept, we took inspiration from the process that led to the creation of the National Institute of Standards and Technology Advanced Encryption Standard (NIST AES). To ensure the integrity and validity of the technical solution, we are building a community of passionate global citizens from varying professional backgrounds. CATALINK is truly an international effort, with funding and political support currently from the Swiss and German governments and in-kind contributions from experts around the world.

What are the shortcomings of current hotlines?
  1. Lack of trust and cooperation: The contemporary security environment has not facilitated the development and implementation of secure hotlines as a security and diplomatic priority. A lack of confidence in the intentions of other states has decreased desire to cooperate and communicate, at a time when the opposite is required to mitigate risks of nuclear war.  
  2. Ineffective history: The current technologies, networks, and systems that hotlines rely on have not been sufficient to lessen threats of conflict escalation. The performance of existing systems is often unreliable and not all nuclear states have access to the technology and technical expertise which could increase technological performance.
  3. Insufficient focus: Broad definitions of hotlines have undermined their implementation. Referring to unencrypted communications as “hotlines” ignores that in order to reduce nuclear risks a hotline needs to be a secure and unbreakable network.  
  4. Insufficient breadth: The presence of nine nuclear armed states (not to mention their allies and adversaries that would undoubtedly be pulled into a potential nuclear crisis) complicates the logistics and technical requirements of designing and has prevented the implementation of a global nuclear communication.
Is there support for strengthening crisis communications?

There is a current emphasis being placed on the need for risk reduction within the nuclear policy community, which was fully evident during the proceedings at the recent 2020 Non-Proliferation Treaty Review Conference. All major governmental and non-governmental risk reduction initiatives (e.g. the P5 Process, Global Enterprise, Stockholm Stepping Stones Initiative, and Nonproliferation and Disarmament Initiative) have recognized the need for improving the current crisis communications architecture. The CATALINK project has provided important concepts for building a system to meet today’s technical and geopolitical realities.

How can CATALINK fit into a broader toolkit of nuclear crisis control?

CATALINK is only one strategic risk reduction effort of many. These additional tools include increased data sharing and transparency, launch notification agreements, more frequent strategic dialogues, and other confidence building measures (CBMS).

The existence of crisis communications between nuclear weapon states has not solved conflict. However, the existence of crisis communication lines between heads of state have played, and will continue to play, a role in limiting escalation between adversaries with nuclear weapons in the midst of violent conflicts. At the very least, these communication lines provide a mechanism for information sharing at a time when misperception and misunderstanding could lead to devastating consequences. That both sides know they can send near instantaneous secure messages to each other is undoubtedly a stabilizing factor. 

How can you factor in the values of differing risk reduction cultures?

States will have the prerogative to use CATALINK how they see fit, consistent with their own strategic cultures, and in agreement with their counterparts.

The CATALINK design concept invites and seeks to integrate feedback from all nuclear weapons states, to encourage the adoption of CATALINK by all states with nuclear weapons. However, the CATALINK team believes that CATALINK can have additive value even if a subset of states with nuclear weapons adopt it. By cultivating the input of experts from all nuclear weapons states into the design concept, the CATALINK team is hopeful that even states who have traditionally differed in approaches to risk reduction may consider adoption of the system.

What are the incentives for states with nuclear weapons to consider and work with  CATALINK?

Secure, resilient crisis communications systems actively reduce the risk of global nuclear war.  Novel risk reduction measures, including additive crisis communication systems like CATALINK, present tangible confidence-building measures which do not necessitate concessions nor acceptance of additional risk from states with nuclear weapons. CATALINK would provide leaders of states with nuclear weapons a secure and resilient thin line crisis communication capability with the option of bilateral or multilateral use. 

The CATALINK concept design takes into account environmental and technical specifications necessary for potential use in the lead-up to a crisis, during a crisis, and in worst cases, post-nuclear exchange.

What role can states without nuclear weapons play?

States without nuclear weapons and civil society groups are critical to the CATALINK initiative and design process. Non-nuclear weapons states can actively contribute to the initiative by taking part in the technical design and proof of concept processes as well as by providing diplomatic support. CATALINK is currently financially and politically supported by the Swiss Federal Department of Foreign Affairs and the German Federal Foreign Office.

Why should states trust CATALINK?

Trust was built from the outset into the CATALINK initiative. The CATALINK design team is composed of international experts and integrates insight from all nuclear weapons states. The primary goal of the CATALINK initiative is to provide a secure, open-source design for use by nuclear weapons states. If states choose to adopt CATALINK, they will use their own trusted supply chains to construct and maintain it. 

CATALINK is supported politically and financially by the Swiss Federal Department of Foreign Affairs and the German Federal Foreign Office. The CATALINK team has briefed a number of states with and without nuclear weapons as part of a global diplomatic campaign to present the system, answer questions, and encourage engagement with the design project. CATALINK draws inspiration from the AES competition (a competition to develop an encryption standard) and looks to it as an excellent example of how trust engendered through international collaboration can increase global security. IST, the current home of the CATALINK team, is a non-profit 501(c)(3) organization. IST is responsible for the design and proof of concept for the CATALINK system, however, states that choose to adopt the CATALINK system will be responsible for its manufacturing and operation, in order to maintain state security and trust. Additionally, in accordance with CATALINK’s commitment to transparency, all prototypical code for the system is open source and viewable on github at any time.

How is CATALINK cyber secure?

Cybersecurity is absolutely critical to any system facilitating communication between leaders of states with nuclear weapons. As offensive cyber actors, both nation state aligned and rogue, become more sophisticated with their attacks, and the means of attack become cheaper, national communication systems face high cyber risk. 

The CATALINK team is acutely aware of these risks and built CATALINK with security at the center of the system. Because complexity is the enemy of security, CATALINK is radically simple. CATALINK users will know what every single line of code does, how every piece of hardware interacts, and where any bugs or vulnerabilities may lie. 

As an additional form of security, with an eye toward the many supply chain exploits that have emerged in recent years, states will not only build their own CATALINK systems (based on design provided by the CATALINK team) but will also source all components and hardware for their systems. States will thus be able to source materials from suppliers that they trust.

Does CATALINK pose espionage risks?

CATALINK is designed to be secure and resilient against espionage. Measures to ensure security include:

  • The CATALINK design calls for physical key exchanges for message encryption before parties are able to send messages to each other. These key exchanges are detailed in CATALINK advisor Eric Grosse’s paper, “Hotline Cryptography.”
  • CATALINK will not be manufactured by third parties. States are responsible for building their own systems. States will not only build their own CATALINK systems (based on design provided by the CATALINK team) but will also source all components and hardware for their systems. States will thus be able to source materials from suppliers that they trust and are familiar with their security precautions. Likewise, the production of CATALINK system components can happen domestically in each state, with governments perhaps preferring to have traditional industry partners build the Puck and Broker from CATALINK designs.
  • CATALINK will use formal methods, a way of mathematically confirming functions or systems, to limit errors in the design.
  • CATALINK will invite red teams from all around the world to try and break into the system in the testing phase, revealing vulnerabilities prior to deployment.

Is CATALINK an NC3 System?

No. CATALINK is intended to be an additive measure, not to replace any existing national communication systems or capabilities. CATALINK is not meant to act as an alternative NC3 system for any state with nuclear weapons. It should be a parallel and separate crisis communications system between states with nuclear weapons. 

How does CATALINK connect or relate to national systems?

CATALINK is designed for use in the lead up to, during, and/or after a conflict, or in the worst case, nuclear war. The way in which this use is realized is up to individual states. As such, states will have the prerogative to connect CATALINK to whatever national systems they deem best. The Puck and Broker will require connection to at least a handful of national systems for optimized utility.

The resilient fallback network for CATALINK, the ROCCS (Resilient Omni Frequency Crisis Communications System), will necessitate shared ownership, as it will constitute a global network. The maintenance and upgrading of that system will be done via prior agreed joint actions between states.

Does CATALINK have to be used for multilateral communication?

CATALINK will possess the option for multilateral communication, but states can decide to use it solely for bilateral communication. It will be apparent to states whether they are using bilateral or multilateral channels, should they choose to have both functions. Likewise, states will decide with whom they want to be able to communicate. It will also be up to state leaders to determine who will use CATALINK, be that the President, the Prime Minister, or whoever is designated to have the prerogative of de-escalation negotiation.

If CATALINK is a multilateral system, can every country see every other country’s messages?

No. Via the physical key exchange as well as encryption, each leader using CATALINK will be able to select a recipient or recipients as they deem fit. No one other than the indicated recipients will be able to see a message. The multilateral functionality of CATALINK is optional; leaders can choose whether they send a message to one, two, or several counterparts.

What are key exchanges and how do they work?

Key exchanges add an additional level of security and reliability to the messages exchanged between leaders using CATALINK. Physical key exchanges have been built into the design of CATALINK, such that no two leaders (or three, or four, etc) may be able to communicate without having done an in-person exchange of encryption keys. The keys are made up of a series of characters that must be inputted before being able to send and receive messages with the relevant counterpart. This process is further detailed in CATALINK advisor Eric Grosse’s paper, “Hotline Cryptography.”

What are the next steps for the CATALINK initiative?

The CATALINK project going forward will focus on 3 lines of effort: (1) furthering technical development and design; (2) diplomatic coalition building; and (3) increasing public understanding of the need for strategic and nuclear risk reduction.

Is CATALINK a commercial product? 

No. IST is a non-profit organization and does not sell products. Rather, the initiative aims to develop a design schematic for the system and then hand it over to states with nuclear weapons so that they may manufacture their own devices. States will also source their own materials for the devices, though IST may provide recommendations on best practices for manufacturing. 

How can I contact the CATALINK team?

Please contact [email protected].