No, because there is no keyring and you have to supply people's public key each time. It is not suitable for large-scale public key management (with unknown recipients), and it does not support automatic discovery, trust management. Age does NOT SUPPORT signing at all either.

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amluto 12 hours ago | parent | next [-]

> you have to supply people's public key each time

Keyrings are awful. I want to supply people’s public keys each time. I have never, in my entire time using cryptography, wanted my tool to guess or infer what key to verify with. (Heck, JOSE has a long history of bugs because it infers the key type, which is also a mistake.)

I have an actual commercial use case that receives messages (which are, awkwardly, files sent over various FTP-like protocols, sigh), decrypts and verifies them, and further processes them. This is fully automated and runs as a service. For horrible legacy reasons, the files are in PGP format. I know the public key with which they are signed (provisioned out of band) and I have the private key for decryption (again, provisioned out of band).

This would be approximately two lines of code using any sane crypto library [0], but there really isn’t an amazing GnuPG alternative that’s compatible enough.

But GnuPG has keyrings, and it really wants to use them and to find them in some home directory. And it wants to identify keys by 32-bit truncated hashes. And it wants to use Web of Trust. And it wants to support a zillion awful formats from the nineties using wildly insecure C code. All of this is actively counterproductive. Even ignoring potential implementation bugs, I have far more code to deal with key rings than actual gpg invocation for useful crypto.

[0] I should really not have to even think about the interaction between decryption and verification. Authenticated decryption should be one operation, or possibly two. But if it’s two, it’s one operation to decapsulate a session key and a second operation to perform authenticated decryption using that key.

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mkesper an hour ago | parent | next [-]

Some years ago I wrote "just a little script" to handle encrypting password-store secrets for multiple recipients. It got quite ugly and much more verbose than planned, switching gpg output parsing to Python for sanity. I think I used a combination of --keyring <mykeyring> --no-default-keyring. Never would encourage anyone to do this again.

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upofadown 2 hours ago | parent | prev [-]

>And it wants to identify keys by 32-bit truncated hashes.

That's 64 bits these days.

>I should really not have to even think about the interaction between decryption and verification.

Messaging involves two verifications. One to insure that you are sending the message to who you think you are sending the message. The other to insure that you know who you received a message from. That is an inherent problem. Yes, you can use a shared key for this but then you end up doing both verifications manually.

	▲	amluto 5 minutes ago \| parent [-]
		>> And it wants to identify keys by 32-bit truncated hashes. > That's 64 bits these days. The fact that it’s short enough that I even need to think about whether it’s a problem is, frankly, pathetic. > Messaging involves two verifications. One to insure that you are sending the message to who you think you are sending the message. The other to insure that you know who you received a message from. That is an inherent problem. Yes, you can use a shared key for this but then you end up doing both verifications manually. I can’t quite tell what you mean. One can build protocols that do encrypt-then-sign, encrypt-and-sign, sign-then-encrypt, or something clever that combines encryption and signing. Encrypt-then-sign has a nice security proof, the other two combinations are often somewhat catastrophically wrong, and using a high quality combination can have good performance and nice security proofs. But all of the above should be the job of the designer of a protocol, not the user of the software. If my peer sends me a message, I should provision keys, and then I should pass those keys to my crypto library along with a message I received (and perhaps whatever session state is needed to detect replays), and my library should either (a) tell me that the message is invalid and not give me a guess as to its contents or (b) tell me it’s valid and give me the contents. I should not need to separately handle decryption and verification, and I should not even be able to do them separately even if I want to.

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some_furry 16 hours ago | parent | prev [-]

Why is a keyring important to you?

Would "fetch a short-lived age public key" serve your use case? If so, then an age plugin that build atop the AuxData feature in my Fediverse Public Key Directory spec might be a solution. https://github.com/fedi-e2ee/public-key-directory-specificat...

But either way, you shouldn't have long-lived public keys used for confidentiality. It's a bad design to do that.

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deknos 4 hours ago | parent | next [-]

We need a keyring at a company. Because there's no other media for communicating, where you reach management and technical people in companies as well.

And we have massive issues due to the fact that the ongoing-decrying of "shut everything off" and the following non-improvement-without-an-alternative because we have to talk with people of other organizations (and every organization runs their own mailserver) and the only really common way of communication is Mail.

And when everyone has a GPG Key, you get.. what? an keyring.

You could say, we do not need gpg, because we control the mailserver, but what if a mailserver is compromised and the mails are still in mailboxes?

the public keys are not that public, only known to the contenders, still, it's an issue and we have a keyring

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johnisgood 16 hours ago | parent | prev [-]

> you shouldn't have long-lived public keys used for confidentiality.

This statement is generic and misleading. Using long-lived keys for confidentiality is bad in real-time messaging, but for non-ephemeral use cases (file encryption, backups, archives) it is completely fine AND desired.

> Would "fetch a short-lived age public key" serve your use case?

Sadly no.

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soatok 16 hours ago | parent [-]

(This is some_furry, I'm currently rate-limited. I thought this warranted a reply, so I switched to this account to break past the limit for a single comment.)

> This statement is generic and misleading.

It may be generic, but it's not misleading.

> Using long-lived keys for confidentiality is bad in real-time messaging, but for non-ephemeral use cases (file encryption, backups, archives) it is completely fine.

What exactly do you mean by "long-lived"?

The "lifetime" of a key being years (for a long-lived backup) is less important than how many encryptions are performed with said key.

The thing you don't want is to encrypt 2^50 messages under the same key. Even if it's cryptographically safe to do that, any post-compromise key rotation will be a fucking nightmare.

The primary reason to use short-lived public keys is to limit the blast radius. Consider these two companies:

Alice Corp. uses the same public key for 30+ years.

Bob Ltd. uses a new public key for each quarter over the same time period.

Both parties might retain the secret key indefinitely, so that if Bob Ltd. needs to retrieve a backup from 22 years ago, they still can.

Now consider what happens if both of them lose their currently-in-use secret key due to a Heartbleed-style attack. Alice has 30 years of disaster recovery to contend with, while Bob only has up to 90 days.

Additionally, file encryption, backups, and archives typically use ephemeral symmetric keys at the bottom of the protocol. Even when a password-based key derivation function is used (and passwords are, for whatever reason, reused), the password hashing function usually has a random salt, thereby guaranteeing uniqueness.

The idea that "backups" magically mean "long-lived" keys are on the table, without nuance, is extremely misleading.

> > Would "fetch a short-lived age public key" serve your use case?

> Sadly no.

shrug Then, ultimately, there is no way to securely satisfy your use case.

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johnisgood 15 hours ago | parent [-]

You introduced "short-lived" vs "long-lived", not me. Long-lived as wall-clock time (months, years) is the default interpretation in this context.

The Alice / Bob comparison is asymmetric in a misleading way. You state Bob Ltd retains all private keys indefinitely. A Heartbleed-style attack on their key storage infrastructure still compromises 30 years of backups, not 90 days. Rotation only helps if only the current operational key is exposed, which is an optimistic threat model you did not specify.

Additionally, your symmetric key point actually supports what I said. If data is encrypted with ephemeral symmetric keys and the asymmetric key only wraps those, the long-lived asymmetric key's exposure does not enable bulk decryption without obtaining each wrapped key individually.

> "There is no way to securely satisfy your use case"

No need to be so dismissive. Personal backup encryption with a long-lived key, passphrase-protected private key, and offline storage is a legitimate threat model. Real-world systems validate this: SSH host keys, KMS master keys, and yes, even PGP, all use long-lived asymmetric keys for confidentiality in non-ephemeral contexts.

And to add to this, incidentally, age (the tool you mentioned) was designed with long-lived recipient keys as the expected use case. There is no built-in key rotation or expiry mechanism because the authors considered it unnecessary for file encryption. If long-lived keys for confidentiality were inherently problematic, age would be a flawed design (so you might want to take it up with them, too).

In any case, yeah, your point about high-fan-out keys with large blast radius is correct. That is different from "long-lived keys are bad for confidentiality" (see above with regarding to "age").

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maxtaco 15 hours ago | parent | next [-]

An intended use case for FOKS (https://foks.pub) is to allow long-lived durable shared secrets between users and teams with key rotation when needed.

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stackghost 10 hours ago | parent | prev [-]

>Personal backup encryption with a long-lived key, passphrase-protected private key, and offline storage is a legitimate threat model

... If you're going to use a passphrase anyway why not just use a symmetric cipher?

In fact for file storage why not use an encrypted disk volume so you don't need to use PGP?

	▲	johnisgood 6 hours ago \| parent [-]
		That was just me being goofy in that bit (and only that), but I hope the rest of my message went across. :) > In fact for file storage why not use an encrypted disk volume so you don't need to use PGP? Different threat models. Disk encryption (LUKS, VeraCrypt, plain dm-crypt) protects against physical theft. Once mounted, everything is plaintext to any process with access. File-level encryption protects files at rest and in transit: backups to untrusted storage, sharing with specific recipients, storing on systems you do not fully control. You cannot send someone a LUKS volume to decrypt one file, and backups of a mounted encrypted volume are plaintext unless you add another layer.