Applied Cryptography Engineer

Job description

Our mission is to defend human rights and democracy through building software that is essential for digital freedom and privacy protection for all Internet users.

ProtonMail was founded in 2014 by a group of scientists who met at the European Organization for Nuclear Research (CERN). And since its inception, the company has grown at a fast pace and today has over 26 million users. Our principal product, ProtonMail, is the world’s largest secure email service. Our second product, ProtonVPN, is one of the world’s most popular VPN services. Our vision is to build an Internet platform for the protection of digital rights, and we are also developing additional products such as ProtonCalendar, ProtonDrive, and much more.

Proton users include leaders of the Hong Kong protest movement, New York Times journalists, some of the world’s largest corporations, and millions of ordinary citizens from over 180 countries. Our team is diverse and dynamic, representing over 30 different nationalities, with offices in Geneva, Zurich, Prague, Vilnius, Skopje, San Francisco, and Taipei

At ProtonMail, we have prioritized the research and development better cryptographic tools and processes. We currently maintain OpenPGP.js, the world's most widely used JavaScript cryptography library, as well as a cryptography library written in Go that is used by our mobile and desktop applications. In addition to maintaining and expanding these libraries, ongoing cryptography-related projects include building a key verification system, source code verification, and preparing for post-quantum crypto. All this work is meant to be compatible with and contribute to the wider OpenPGP community. 

Job requirements

  • Strong background in computer science (algorithms, data structure, software design, reliability, maintainability, etc)
  • Knowledge of JavaScript and/or Go (the two languages in which our cryptography libraries are written)
  • Strong English communication skills
  • Experience with secure application development, a good understanding of security best practices, and a keen eye for potential vulnerabilities
  • High-level knowledge of cryptographic building blocks, including what they guarantee and when and how to use them


The following are considered a plus:

  • Low-level knowledge of crypto primitives, how they work, and how to securely implement them
  • Experience developing crypto libraries
  • Experience reading, implementing and perhaps even writing RFC-style specifications
  • B.S. and/or M.S. in Computer Science or Mathematics (or equivalent)


Why you should join Proton:

  • We work on interesting, challenging problems every day. There is never a dull moment.
  • Our startup culture means everyone’s opinion matters. You can have a significant impact.
  • Our rapid growth means there are many opportunities for advancement.
  • The chance to do something meaningful. Proton products protect dissidents, journalists, and activists. Our work saves lives.
  • Be part of something bigger. Millions of people and businesses around the world have embraced our idea of an Internet where privacy and security are the default. Join the privacy revolution that is changing the world.

ProtonMail is using Recruitee recruitment platform for more effective hiring and better candidate experience. Your data will be kept confidential and not shared with any third parties.

Keep in mind that you will receive emails from email or other addresses on the domain.