Verifpal is new software for verifying the security of cryptographic protocols. Building upon contemporary research in symbolic formal verification, Verifpal’s main aim is to appeal more to real-world practitioners, students and engineers without sacrificing comprehensive formal verification features.
In order to achieve this, Verifpal introduces a new, intuitive language for modeling protocols that is much easier to write and understand than the languages employed by existing tools. At the same time, Verifpal is able to model protocols under an active attacker with unbounded sessions and fresh values, and supports queries for advanced security properties such as forward secrecy or key compromise impersonation.
Verifpal has already been used to verify security properties for Signal, Scuttlebutt, TLS 1.3, Telegram and other protocols. It is a community-focused project, and available under a GPLv3 license.
An Intuitive Protocol Modeling Language
The Verifpal language is meant to illustrate protocols close to how one may describe them in an informal conversation, while still being precise and expressive enough for formal modeling. Verifpal reasons about the protocol model with explicit principals: Alice and Bob exist and have independent states.
Modeling that Avoids User Error
Verifpal does not allow users to define their own cryptographic primitives. Instead, it comes with built-in cryptographic functions — this is meant to remove the potential for users to define fundamental cryptographic operations incorrectly.
Easy to Understand Analysis Output
When a contradiction is found for a query, the result is related in a readable format that ties the attack to a real-world scenario. This is done by using terminology to indicate how the attack could have been possible, such as through a man-in-the-middle on ephemeral keys.
Friendly and Integrated Software
Verifpal comes with a Visual Studio Code extension that offers syntax highlighting and, soon, live query verification within Visual Studio Code, allowing developers to obtain insights on their model as they are writing it.
Verifpal is available for Windows, Linux and macOS. The Verifpal User Manual is an essential guide to getting started with cryptographic protocol analysis using Verifpal: please click the User Manual cover to download your copy.
Verifpal is free and open source software. Source code is available on the 💾Verifpal Source Repository.
On Linux and macOS, quick (and less safe) installation
is possible by running:
bash -c "curl -sL
About the Project
Verifpal is Experimental Software
Verifpal is still highly experimental software. Using it in a classroom or learning environment is welcome, but it should not yet be relied upon for academic formal verification work. For that, check out ProVerif.
News and Discussion
Sign up to the 📧Verifpal Mailing List to stay informed on the latest news and announcements regarding Verifpal, and to participate in Verifpal discussions.
A 📄Verifpal Scientific Paper is available for those interested in the project’s technical and research motivations.
Stickers and Wallpapers
Sponsors and Donations
Verifpal is sponsored by the NLNet Foundation. Funding was provided through the NGI0 Privacy Enhancing Technologies Fund, a fund established by NLnet with financial support from the European Commission’s Next Generation Internet program, under the aegis of DG Communications Networks, Content and Technology under grant agreement №825310.
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Verifpal is published by Symbolic Software. It is provided as free and open source software, licensed under the GNU General Public License, version 3. The Verifpal User Manual, as well as this website, are provided under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) license.