>but I'm not familiar with any of the alternative tools they mentioned.

The tinfoil hat part of me has been seeing this push for the Signal protocol straight out of nowhere and am a little worried its being done by a state level actor who knows something about it that we don't. Its much younger than PGP and as such has had less eyes on it. I also don't think Moxie Marlinspike, the founder of Signal's owner - Open Whisper, has the cred and trust Phil Zimmerman had, at least not yet. Its particularly worrisome as he seemingly is only known by a pseudonym.

I also would consier S/MIME, which is baked into most feature-heavy email clients including iOS, a practical alternative to PGP when the use case is email encryption. You and a friend can get certs easily, put them in your client via GUI, and be done with it. No command line skills needed if ease of use is the big complaint here. For the less technically inclined its a pretty good solution, pun intended.

if you knew the story you'd know that Phil did actually an abysmal implementation which had to fixed by others.

I think I've read about Phil's shortcomings, but in the end he made it happen both technically and politically. I'm ok with software being a community effort and the less talented being helped by the more. Its a group effort to me and I don't believe in the coder superman mythos is required for good software. Not everyone can be a Linus or a Carmack.

opmsg does masquerade as gnupg on the cli, if you take this further you could create a gnupg chameleon which detects what keys are available or what the input is based on auxillary info and then invoke the appropriate tool (which might be gnupg, or something else).

on a different note: gnupg is not widely used, signal is.

Signal is for text messaging and fails as an email replacement. It also does not work for signing code and it requires you give over your contacts list to a third party to work.

Signal is not fit for PGP's use case.

Signal is actually quite sufficient as an email replacement. You can send media attachments, and even include several recipients. It is unquestionably a better encrypted messaging system than PGP.

"It is unquestionably a better encrypted messaging system than PGP." You're going to have to back that up. In no way is Signal more secure or private than PGP. Signal is simply easier to use for a very small use case, text messaging.

Unless you actually need to send email with Signal, or want to be anonymous, since Signal uses your phone number.

pgp does not provide anonymity at least not in the widely accepted form. every message has the recipient keyid in plaintext, unless you --throw-keyids but then you run into incompatibilities and inconveniences that make the whole exercise user unfriendly and widely unsupported.

> pgp does not provide anonymity

Not quite true.

> every message has the recipient keyid in plaintext

The keys are not required to be centralized in any particular location. There is no way to tie a key to an individual, unless that individual wants to be associated with that key id.

It's common practice to post anonymous, encrypted messages on mailing lists or newsgroups. All you can really tell in those cases is that the recipient is a member of that mailing list or subscribes to the newsgroup (though it's not for sure, with the use of remailers, etc).

It provides pseudonymity. KeyIDs exist but they're not inherently tied to e.g. your real-world location the way a phone number is (to an attacker with access to the towers). Whereas OpenPGP can reasonably be combined with e.g. Tor.

By the way, is it possible to use Signal to communicate with people using WhatsApp? Probably stupid question, but since they both use Signal protocol, phone number and stuff I would guess it should be possible to write a bridge that reveals to the MITM (FB) only your phone and the fact you are talking to the person they know, and blatantly lie about everything else, such as your contacts, seen messages (if desired), etc.

> media attachments

How large?

> several recipients

How many, in what countries?

Is the communication anonymous?

Can I use it in such a way that obfuscates the message's recipient?

Can I send an encrypted message when the Signal servers have been DOSed?

If seized, can the controllers of the Signal servers get the contents of my entire phone contact list?

I believe that Signal is adequate for a small subset of encrypted message cases, but not as a good replacement for encrypted emails.

Larger than the 10 MB attachment limit of most email providers.

I'm unaware that Signal is geographically limited in any way.

Signal is anonymous as your phone number is. PGP isn't anonymous either, so this seems like an irrelevant criticism.

Again, you can obfuscate the recipient as much as you can obfuscate a phone number. You can't obfuscate the email address you're sending your encrypted email to.

This depends on how they use contacts to match users. I believe they only collect a hash of the phone numbers you choose to share with them.

PGP is, supposedly, "Pretty Good Privacy". Code signing has nothing to do with privacy.

It's true that PGP is a very good code signing system, but saying that sounds like an endorsement of PGP as a privacy system. (And there are plenty of other good code signing systems, from TUF to Authenticode to signify.)

You've intentionally reduced PGP to your narrow use case. PGP/GPG will also sign and not just encrypt. If you're going to debate the subject do so honestly.

Yes, that's my point. PGP/GPG's ability to sign things is an "also", but it's the only thing it's good at. Build a version of GPG that only does signing and verification, and nobody will be tempted to use it for privacy.

Signing is an integral part of a good encryption scheme, to prevent against certain oracle attacks. The two functions are not so easily separated (if you're offering encryption).

Is the sort of signing you want to do for code signing related to the sort of signing you want to do as part of an encryption scheme?

This vaguely sounds similar to how RSA decryption/encryption and signing/verification are the same sets of operations, at the primitive level, making it easy to turn a tool that does one in to a tool that also does the other. But the actual high-level signing and encryption systems (e.g. RSA-PSS and RSA-OAEP) are not the same operations at all, and being good at one is no guarantee of being good at another.

> Is the sort of signing you want to do for code signing related to the sort of signing you want to do as part of an encryption scheme?

Same basic concept. Take a blob (compiled code or cyphertext) and a private key and sign it, so can be verified with the public key later.

https://en.wikipedia.org/wiki/Authenticated_encryption

This kind of PGP signing is also critical to the security of Linux software repos. Debian repos sign the contents of the manifest (which includes hashes of packages), and Apt repos sign individual files.

These aren't related at all! Authenticated encryption uses a symmetric MAC. Code signing is asymmetric.

I just want to point out that this comment chain is conflating Signal the app with Signal the crypto protocol, which is not specific to SMS

Signal? Some paid services seem to be blossoming, see https://protonmail.com

Signal is not much of a PGP replacement. There's a lot that PGP can do that Signal can't: signing, encryption of large blobs at rest, and key management.

I use PGP as part of my backup solution, encrypting my backups at rest with an asymmetric key. I can't do that with Signal.

Signal does a better job of practically everything PGP does with regards to message encryption. Yes, PGP is more useful for encrypting files or signing updates. I agree that it's too early to write of PGP for those applications. But people should use Signal instead of PGP for message encryption.

> But people should use Signal instead of PGP for message encryption.

I won't disagree; when your usecase is in Signal's wheelhouse, by all means, use it.

But as someone who uses PGP regularly; the limit of how I could use Signal instead of PGP is limited to the occasional transfer of PII, passphrases, and private keys (something I couldn't use Signal for, since these are typically sent between GUI-less hosts). A very tiny fraction of my PGP usage.

"Signal does a better job of practically everything PGP does with regards to message encryption."

Except for endpoint security. The ultra-portable, self-contained implementations of PGP can run on countless configurations of desktop or embedded system. Transport methods also vary if they're funning messages or files through other apps. All sorts of hardening or isolation techniques can be applied. Remote attackers have a lot to look at trying to break or bypass GPG for an arbitrary user. Whereas, vast majority of Signal use relies on one app with two OS's.

The extra security tech and obfuscation you can layer on PGP/GPG is still an advantage in its favor until competition gets that.

> But people should use Signal instead of PGP for message encryption.

Signal the protocol or Signal the service? There does not appear to be a mature FOSS toolchain for the former that can replace gnupg and Thunderbird/Enigmail, and the latter is only available on Android and IOS smartphones.

Don't use email to send secret messages.

Any chance you could elaborate on this? What about email is inimical to secret messages? Why are they less secret over email than through some other medium?

How would that work? Last I checked, Signal used Signal servers for key exchange (or whatever the equivalent in their lingo is). Is there any way to use Signal without relying on their servers?

Protonmail uses PGP............

Quite a few listed here - https://alternativeto.net/software/gnupg/

This is an unvetted list of random programs that claim to perform this- or that- cryptographic operation; it's not really helpful.

There are quite a few things listed there, but I fail to see one that looks like a replacement for PGP. Many are some form of PGP compatible encryption - some different platforms Android(AGP), Windows(GPG4Win, Fort) Apple(GPG Suite for apple mail). Some will only encrypt files with a password, others encrypt your disk. There might be some good software there, but I don't see anything that can replace PGP/GnuPG.

Using PGP/GnuPG isn't always easy, but it works for so many things. Signing code, encrypting files, emails, signing messages - replacing it is a fairly high bar.

I'd love to see encryption easy and used everywhere, but a few popular apps don't add up to replacing this old work horse.

check out opmsg how it achieves compatibility with gnupg and imagine a tool that actually looks like gpg but figures out which crypto backend to call.

Interesting project, but I'd personally want to see a lot more involvement and vetting from the crypto community at large. Especially when it creates new protocols like DH key exchange over email.