OpenPGP card support in Sequoia

Over the last months we’ve worked on adding support for OpenPGP card hardware tokens to Sequoia. OpenPGP cards (like the free Gnuk implementation, or e.g. Nitrokey and YubiKey devices) are great when you want to use an OpenPGP key, but don’t want the private key material stored on your computer. Advanced OpenPGP users have come to expect their software to support them.

Earlier this month, we connected a set of physical cards to our continuous integration (CI) machine and configured a job to run a test suite on these cards. This setup ensures that every change to our code is tested on a set of physical OpenPGP cards. The ability to test against multiple cards is essential, as cards implement different versions of the specification, and, on top of that, many have various quirks.

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Octopus 1.2 is Released

I’m pleased to announce a new release of the Octopus, an alternative OpenPGP backend for Thunderbird. This release brings several compatibility improvements with newer versions of Thunderbird, a few bug fixes, and some documentation improvements. And, it changes the Octopus' license from the GPL to the LGPL to be consistent with our recent relicensing of the Sequoia libraries.

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The Future of Sequoia PGP

NLnet recently held a webinar on the future of OpenPGP. The Sequoia team made five short presentations. In addition to an introduction summarizing the past, present, and future of Sequoia, we presented four of our current projects, which provide a nice cross section of our current work.

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Sequoia PGP is now LGPL 2.0+

We’re happy to announce that we’ve changed Sequoia PGP’s license from the GPL 2+ to the more permissive LGPL 2+. Simultaneously, we’ve also released version 1.5 of the openpgp crate under these terms.

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Sequoia 1.4 is released

We’re happy to announce the release of version 1.4 of our low-level OpenPGP library. The most prominent change is the addition of a new cryptographic backend based on the RustCrypto crates.

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Yes, We Want Cryptographic Protection for Email

The EFAIL attacks demonstrate that securing email is hard. Incautious improvements to usability can lead to critical security vulnerabilities. In the case of EFAIL, an attacker could exploit mail clients that show corrupted messages to exfiltrate a message’s plain text.

Although the EFAIL researchers are measured in their response, others, like Thomas Ptacek in his widely cited articles The PGP Problem from 2019, and Stop Using Encrypted Email from 2020, are calling for people to abandon OpenPGP, and give up on secure email. Instead, they argue, people should use secure messengers like Signal.

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Hey Signal! Great Encryption Needs Great Authentication

In 2017, Moxie Marlinspike and Trevor Perrin were awarded the The Levchin Prize for Real-World Cryptography for developing the Signal protocol. It’s a well-earned honor and I have no doubt that Signal is the best practical in-class encryption scheme for messaging that the cryptographic community knows about.

But, securing communication requires more than encryption. The sender also needs to make sure the public keys that they intend to use are the right keys for the intended recipients. This check is called authentication. If the sender uses the wrong public key then either the recipient won’t be able to read the message, or worse, an active attacker could intercept the message, and reencrypt it on the fly so that the connection appears to be secure when in fact someone is eavesdropping.

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Sequoia 1.3 is released

We’re happy to announce the release of version 1.3 of our low-level OpenPGP library. For those of you following along at home, you’re probably asking what happened to 1.2. This past Sunday was PGP’s 30th birthday. To celebrate three decades of PGP, we’ve decided to skip 1.2 and directly release 1.3.

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A Look at Two Recent CVEs in Thunderbird's OpenPGP Support

In a blog post that I published two weeks ago, I wrote that RNP is dangerous, because it is too easy to misuse. I also explained how we avoid those problems in Sequoia. In this blog post, I will lay out how not one, but two CVEs have since come up in Thunderbird that seem to underline that danger.

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Hello, OpenPGP CA!

We are pleased to share that version 0.10.1 of OpenPGP CA has been released! This is also the first version which is available on

OpenPGP CA is a tool for administrators to create and manage a decentralized, in-house certification authority. OpenPGP CA makes it possible and easy for an organization to delegate authentication decisions to someone they can rely on, like their system administrator. And, external groups and individuals can use these CAs to authenticate certificates for just that organization using OpenPGP’s scoped trust signatures. OpenPGP CA also helps with key discovery and key updates by managing a Web Key Directory (WKD).

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