The PGP problem (2019)

https://github.com/fedi-e2ee/public-key-directory-specificat...

My current project aims to bring Key Transparency to the Fediverse for building E2EE on ActivityPub so you can have DMs that are private even against instance moderators.

One of the things I added to this design was the idea of "Auxiliary Data" which would be included in the transparency log. Each AuxData has a type identifier (e.g. "ssh-v2", "age-v1", "minisign-v0", but on the client-side, you can have friendly aliases like just "ssh" or "age"). The type identifier tells the server (and other clients) which "extension" to use to validate that the data is valid. (This is to minimize the risk of abuse.)

As this project matures, it will be increasingly easy to do this:

  // @var pkdClient -- A thin client-side library that queries the Public Key Directory
  // @var age -- An implementation of age
  async function forwardSecureEncrypt(file, identity) {
    const agePKs = await pkdClient.FetchAuxData(identity, "age");
    if (agePKs.length === 0) {
      throw new Error("No age public keys found");
    }
    return age.Encrypt(file, agePKs[0]);
  }

(The degree of "forward secure" here depends on how often your recipient adds a new age key and revokes their old one. Revocation is also published through the transparency log.)

However, email encryption is such a mess that most people don't quite appreciate, so I'm blogging about that right now. :)

Also, Filippo just created a transparency-based keyserver for age, fwiw: https://words.filippo.io/keyserver-tlog/

I reviewed Signal's cryptography last year over a long weekend: https://soatok.blog/2025/02/18/reviewing-the-cryptography-us...

There's a lot to be said for the utility of reverse engineering tools and skills, but I did not need them, because it was open source. Because Signal's client software still is open source.

Whatever you think about MobileCoin, it doesn't actually intersect with the message encryption features at all. At all.

The only part in Signal that's not entirely open source are the anti-spam features baked into the Signal Server software.

And, frankly, the security of end-to-end encryption messaging apps has so little to do with whatever the server software is doing that it's frankly silly to consider that relevant to these discussions. https://soatok.blog/2025/07/09/jurisdiction-is-nearly-irrele...

And, yes, this is only a server-side feature. See spam-filter (a git submodule) in https://github.com/signalapp/Signal-Server but absent from https://github.com/signalapp/Signal-Android or https://github.com/signalapp/Signal-iOS

> The Signal people are absolutely not trustworthy for reasons of money and greed.

I don't think you've raised sufficient justification for this point.

It looks like there are some wrapper scripts to make git sign commits with other tools using the GPG cli interface but nothing official.