Retrieval-Augmented Generation (RAG) is probably the tech you’d want. It basically involves a knowledge library being built from the documents you upload, which is then indexed when you ask questions.

NotebookLM by Google is an off the shelf tool that is specialized in this, but you can upload documents to ChatGPT, Copilot, Claude, etc., and get the same benefit.

If you self hosted, Open WebUI with Ollama supports this, but far from the only one.

You can self-host Bitwarden, too. My understanding is that VaultWarden is much simpler to self-host, though. Note that VaultWarden isn’t a “fork”; it’s a compatible rewrite in Rust (Bitwarden’s codebase, by contrast, is primarily C#).

I also use Bitwarden and strongly prefer it over every other password manager I’ve tried or investigated, for what that’s worth. I’d recommend it to 99% of non-enterprise users (it’s probably great for enterprise use as well, TBF).

The only use case I wouldn’t recommend it for is when you don’t want your passwords stored in the cloud, in which case KeePass is the way to go. To be clear, that recommendation does not apply if you’re syncing your vault with a cloud storage provider - even one you’re hosting, like SyncThing - even if your vault is encrypted. At that point just use Bitwarden or VaultWarden, because they’re at least audited with your use case in mind (Vaultwarden has only been audited once afaik, though).

Sure, but mortgage interest can easily be enough to make that worth it without any other deductions. With $300K principal and a 5% loan, that’s $15K - about the same as a single taxpayer’s standard deduction and roughly half of a married couple’s standard deduction.

I don’t think gravitational waves traveling at the speed of light is the same as the gravitational attraction being apparently felt faster than light travels.

I don’t know how you would measure gravitational waves without measuring gravitational attraction.

It’s not light that is “communicating” that attraction.

Nobody said it was. The “speed of light” isn’t about “light”. Gravity propagates at the same speed, aka “c.”

This Reddit discussion on r/AskPhysics might help clear up your misconceptions. Notably:

Just to clarify: when people talk about the speed of gravity, they mean the speed at which changes propagate. It’s the answer to questions like: if I take the Sun and wiggle it around, how long does it take for the Earth to feel the varitation in the force of gravity? And the answer is that changes in gravity travel at the speed of light.

But that’s not what you’re asking about. Whenever you’re close to the Earth, gravity is always acting on you: it’s not waiting until you step off a cliff, like in the Coyote and the Roadrunner. The very instant your foot is no longer on the ground, gravity will start to move it downwards. The only detail is that it takes some time for it to build up an appreciable speed, and this is what allows us to do stuff like jump over pits: if you’re fast enough, gravity won’t be able to accelerate you enough - but gravity is still there.

I get the sense that you’re thinking about the second scenario when objecting to the concept that gravity travels at the speed of light.

https://bigthink.com/hard-science/speed-of-gravity/

I’m familiar with SSL in the context of webdev, where SSL (well, TLS) is standard, but there the standard only uses server certificates. Even as a best practice, consumer use cases for client certificates, where each client has a unique certificate, are extremely rare. In an app, I would assume that’s equally true, but that shared client certificates - where every install from Google Play uses the same certificate, possibly rotated from version to version, and likewise with other platforms, like the App Store, the apk you can download from their site, F-Droid, if they were on it, and releases of other apps that use the same servers, like Molly. Other platforms might share the same key or have different keys, but in either case, they’re shared among millions of users.

I’m not sure Signal does have a client certificate, but I believe they do have a shared API access key that isn’t part of the source code, and which they (at least previously) prohibited the use of by FOSS forks (and refused to grant them their own key)

That said, I reviewed that code, and while I’m not a big fan of Java and I’m not familiar with the Android APIs, I’m familiar with TLS connections in webdev, the terms are pretty similar cross-language, and I did work in Java for about five years, but I didn’t see anything when reviewing that file that makes me think client certificates are being generated or used. Can you elaborate on what I’m missing?

Clearly they’re cosplaying as a Canonical engineer whose internal explanation and pleas for them to not take this approach fell upon deaf ears /j

you’re the only one with your SSL keys. As part of authentication, you are identified. All the information about your device is transmitted. Then you stop identifying yourself in future messages, but your SSL keys tie your messages together. They are discarded once the message is decrypted by the server, so your messages should in theory be anonymised in the case of a leak to a third party. That seems to be what sealed sender is designed for, but it isn’t what I’m concerned about.

Why do you think that Signal uses SSL client keys or that it transmits unique information about your device? Do you have a source for that or is it just an assumption?

If you’re a C developer who doesn’t know Rust, yes.

And it’s I who should take a course in encryption and cybersecurity.

Yes. I was trying to be nice, but you’re clearly completely ignorant and misinformed when it comes to information security. Given that you self described as a “cryptography nerd,” it’s honestly embarrassing.

But since you’ve doubled down on being rude, just because I pointed out that you don’t know what you’re talking about, it’s unlikely you’ll ever learn enough about the topic to have a productive conversation, anyway.

Have fun protecting your ignorance.

Nice try FBI.

Wouldn’t “NSA” or “CIA” be more appropriate here?

Well, if my pin is four numbers, that’ll make it so hard to crack. /s

If you’re using a 4 number PIN then that’s on you. The blog post I shared covers that explicitly: “However, there’s a limit to how slow things can get without affecting legitimate client performance, and some user-chosen passwords may be so weak that no feasible amount of “key-stretching” will prevent brute force attacks” and later, “However, it would allow an attacker with access to the service to run an “offline” brute force attack. Users with a BIP39 passphrase (as above) would be safe against such a brute force, but even with an expensive KDF like Argon2, users who prefer a more memorable passphrase might not be, depending on the amount of money the attacker wants to spend on the attack.”

If you can’t show hard evidence that everything is offline locally, no keys stored in the cloud, then it’s just not secure.

If you can’t share a reputable source backing up that claim, along with a definition of what “secure” means, then your claim that “it’s just not secure” isn’t worth the bits taken to store the text in your comment.

You haven’t even specified your threat model.

BTW, “keys” when talking about encryption is the keys used to encrypt and decrypt,

Are you being earnest here? First, even if we were just talking about encryption, the question of what’s being encrypted is relevant. Secondly, we weren’t just talking about encryption. Here’s your complete comment, for reference:

I have read that it is self hostable (but I haven’t digged into it) but as it’s not a federating service so not better than other alternative out there.

Also read that the keys are stored locally but also somehow stored in the cloud (??), which makes it all completely worthless if it is true.

That said, the three letter agencies can probably get in any android/apple phones if they want to, like I’m not forgetting the oh so convenient “bug” heartbleed…

Just so you know, “keys” are used for a number of purposes in Signal (and for software applications in general) and not all of those purposes involve encryption. Many keys are used for verification/authentication.

Assuming you were being earnest: I recommend that you take some courses on encryption and cybersecurity, because you have some clear misconceptions. Specifically, I recommend that you start with Cryptography I (by Stanford, hosted on Coursera. See also Stanford’s page for the course, which contains a link to the free textbook). Its follow-up, Crypto II, isn’t available on Coursera, but I believe that this 8 hour long Youtube video contains several of the lectures from it. Alternatively, Berkeley’s Zero Knowledge Proofs course would be a good follow-up, and basically everything (excepting the quizzes) appears to be freely available online.

it wouldn’t be very interesting to encrypt them, because now you have another set of keys you have to deal with.

The link I shared with you has 6 keys (stretched_key, auth_key, c1, c2, master_key, and application_key) in a single code block. By encrypting the master key (used to derive application keys such as the one that encrypts social graph information) with a user-derived, stretched key, Signal can offer an optional feature: the ability to recover that encrypted information if their device is lost, stolen, wiped, etc., though of course message history is out of scope.

Full disk encryption also uses multiple keys in a similar way. Take LUKS, for example. Your drive is encrypted with a master key. You derive the master key by decrypting one of the access keys using its corresponding pass phrase. (Source: section 4.3 in the LUKS1 On-Disk Format Specification (I don’t believe this basic behavior was changed in LUKS2).)

Its impossible to verify what code their server is running.

Signal has posted multiple times about their use of SGX Secure Enclaves and how you can use Remote Attestation techniques to verify a subset of the code that’s running on their server, which directly contradicts your claim. (It doesn’t contradict the claim that you cannot verify all the code their server is running, though.) Have you looked into that? What issues did you find with it?

I posted a comment here going into more detail about it, but I haven’t personally confirmed myself that it’s feasible.

The sender ('s unique device) can with 100% accuracy be appended to the message by the server after it’s received.

How?

If I share an IP with 100 million other Signal users and I send a sealed sender message, how does Signal distinguish between me and the other 100 million users? My sender certificate is encrypted and only able to be decrypted by the recipient.

If I’m the only user with my IP address, then sure, Signal could identify me. I can use a VPN or similar technology if I’m concerned about this, of course. Signal doesn’t consider obscuring IPs to be in scope for their mission - there was a recent Cloudflare vulnerability that impacted Signal where they mentioned this. From https://www.404media.co/cloudflare-issue-can-leak-chat-app-users-broad-location/

404 Media asked daniel to demonstrate the issue by learning the location of multiple Signal users with their consent. In one case, daniel sent a user an image. Soon after, daniel sent a link to a Google Maps page showing the city the user was likely in.

…

404 Media first asked Signal for comment in early December. The organization did not provide a statement in time for publication, but daniel shared their response to his bug report.

“What you’re describing (observing cache hits and misses) is a generic property of how Content Distribution Networks function. Signal’s use of CDNs is neither unique nor alarming, and also doesn’t impact Signal’s end-to-end encryption. CDNs are utilized by every popular application and website on the internet, and they are essential for high-performance and reliability while serving a global audience,” Signal’s security team wrote.

“There is already a large body of existing work that explores this topic in detail, but if someone needs to completely obscure their network location (especially at a level as coarse and imprecise as the example that appears in your video) a VPN is absolutely necessary. That functionality falls outside of Signal’s scope. Signal protects the privacy of your messages and calls, but it has never attempted to fully replicate the set of network-layer anonymity features that projects like Wireguard, Tor, and other open-source VPN software can provide,” it added.

I saw a post about this recently on Lemmy (and Reddit), so there’s probably more discussion there.

since the sender is identified at the start of every conversation.

What do you mean when you say “conversation” here? Do you mean when you first access a user’s profile key, which is required to send a sealed sender message to them if they haven’t enabled “Allow From Anyone” in their settings? If so, then yes, the sender’s identity when requesting the contact would necessarily be exposed. If the recipient has that option enabled, that’s not necessarily true, but I don’t know for sure.

Even if we trust Signal, with Sealed Sender, without any sort of random delay in message delivery, a nation-state level adversary could observe inbound and outbound network activity and derive high confidence information about who’s contacting whom.

All of that said, my understanding is that contact discovery is a bigger vulnerability than Sealed Sender if we don’t trust Signal’s servers. Here’s the blog post from 2017 where Moxie describe their approach. (See also this blog post where they talk about improvements to “Oblivious RAM,” though it doesn’t have more information on SGX.) He basically said “This solution isn’t great if you don’t trust that the servers are running verified code.”

This method of contact discovery isn’t ideal because of these shortcomings, but at the very least the Signal service’s design does not depend on knowledge of a user’s social graph in order to function. This has meant that if you trust the Signal service to be running the published server source code, then the Signal service has no durable knowledge of a user’s social graph if it is hacked or subpoenaed.

He then continued on to describe their use of SGX and remote attestation over a network, which was touched on in the Sealed Sender post. Specifically:

Modern Intel chips support a feature called Software Guard Extensions (SGX). SGX allows applications to provision a “secure enclave” that is isolated from the host operating system and kernel, similar to technologies like ARM’s TrustZone. SGX enclaves also support a feature called remote attestation. Remote attestation provides a cryptographic guarantee of the code that is running in a remote enclave over a network.

Later in that blog post, Moxie says “The enclave code builds reproducibly, so anyone can verify that the published source code corresponds to the MRENCLAVE value of the remote enclave.” But how do we actually perform this remote attestation? And is it as secure and reliable as Signal attests?

In the docs for the “auditee” application, the Examples page provides some additional information and describes how to use their tool to verify the MRENCLAVE value. Note that they also say that the tool is a work in progress and shouldn’t be trusted. The Intel SGX documentation likely has information as well, but most of the links that I found were dead, so I didn’t investigate further.

A blog post titled Enhancing trust for SGX enclaves raised some concerns with SGX’s current implementation, specifically mentioning Signal’s usage, and suggested (and implemented) some improvements.

I haven’t personally verified the MRENCLAVE values for any of Signal’s services and I’m not aware of anyone who has (successfully, at least), but I also haven’t seen any security experts stating that the technology is unsound or doesn’t actually do what’s claimed.

Finally, I recommend you check out https://community.signalusers.org/t/overview-of-third-party-security-audits/13243 - some of the issues noted there involve the social graph and at least one involves Sealed Sender specifically (though the link is dead; I didn’t check to see if the Internet Archive has a backup).

Message history won’t be fully fixed. It can’t be without storing message backups in some cloud somewhere (whether it’s to iCloud, Google Drive, Dropbox, or Signal’s servers) and Signal omits its message history from system backups on iOS and Android.

iOS users are completely incapable of backing up their message history in the event of their phone being lost, stolen, or broken. This omission isn’t justified in any way, as far as I’m aware; I don’t know of any technical reason why following the exact same process as on Android wouldn’t work.

Android users are able to back up locally via Signal, but that isn’t on by default, can’t be automated, needs to be backed up separately, requires you to record a 30 digit code to decrypt it, and has limitations on when it can be used for a restore (can’t restore on iOS, for example). See https://support.signal.org/hc/en-us/articles/360007059752-Backup-and-Restore-Messages for more details.

Message history on linked devices - meaning iPads and desktop computers - is being improved, but it still won’t mean that a user who loses or trades in their phone as they get a new phone will be able to simply restore their phone from a system backup and restore their Signal message history. And even that isn’t anywhere near as easy as on Telegram, where a user can just log in with their password and restore their message history, no backup needed.

It’s great that they’re improving the experience for linked devices, but right now that doesn’t actually help if you lose, break, or trade in your phone. Maybe they’ll later allow users to restore to a phone from a linked device or support backups on iPhones, but right now the situation with message history isn’t just an unfriendly UX, but one that is explicitly and intentionally unreliable for a huge portion of Signal’s user-base.

Also read that the keys are stored locally but also somehow stored in the cloud (??),

Which keys? Are they always stored or are they only stored under certain conditions? Are they encrypted as well? End to end encrypted?

which makes it all completely worthless if it is true.

It doesn’t, because what you described above could be fine or could have huge security ramifications. As it is, my guess is that you’re talking about how Signal supports secure value recovery. In that case:

1. The key is used to encrypt your contacts, profile name, group avatars, social graph, etc., but not your messages.
2. Your key is only uploaded to the cloud if you have a recovery PIN or passphrase
3. Your key is encrypted using your PIN or passphrase using techniques (key-stretching, storing in server secure enclaves) that make it more difficult to brute force

The main criticism of this is that you can’t opt out of it without opting out of the Registration Lock, that it necessarily uses the same PIN or passphrase, and that, particularly because it isn’t clear that your PIN/passphrase is used for encryption, users are less likely to use more secure pass phrases here.

But even without the extra steps that we can’t 100% confirm, like the use of the Secure Enclave on servers and so on, this is e2ee, able to be opted out by the user, not able to be used to recover past messages, and not able to be used to decrypt future messages.

The concern is valid, and it has caused a lot of distrust in many companies due to the Snowden leaks, but that distrust is founded in the leaks.

Snowden explicitly endorsed Signal, too - and as far as I know he’s never walked that endorsement back.

https://signal.org/blog/sealed-sender/ explains the feature.

https://github.com/signalapp/Signal-Android/issues/13842 has some links into the code base showing where sealed sender is implemented.

That’s worth considering, but it also needs to be weighed against possibly impacting their friendship if she’s not interested. I also wouldn’t recommend saying he “really likes her” if he doesn’t already like her a lot that way, but even just “I like you” would work just as well.

Liking multiple people at once is super common. The love triangle is a trope for a reason.

If you don’t like her then don’t worry about it (other than to maybe pay attention to how you’re acting around her and avoid flirting unintentionally) but if you’re interested in her, maybe try pursuing that? Flirt with her a bit and see if she reciprocates. If she likes you, there’s a good chance she’s been flirting with you and you’ve just been oblivious.

If you’re too shy to intentionally flirt, you could ask her outright, but it’d probably be better to ask her something that hints at your interest, like “I like this girl but I can’t tell if she’s into me - what sorts of signs should I be looking for?” Should be pretty obvious what you’re both saying and asking.

Learn, understand, challenge, repeat.

Learn as much as you can about all sorts of topics, even if you don’t have specific plans for those topics

Learn enough that you don’t just know the facts, but that you actually understand why things are the way they are. You should be able to predict things you haven’t yet learned if you understand the concepts. If you don’t understand something yet, keep learning.

Learn your fundamentals: language skills, math, logic, statistics, the science of research, history, politics, basic psychology, and the physics of whatever realm you’re operating in (meaning that in today’s day and age, you should learn about both real-world physics and about how information flows on the Internet).

A lot of people don’t know how to teach themselves, so it’s probably important to point out that learning to do so effectively is a big part of thinking for yourself. Learning how information is presented, as well as what’s often left unsaid, is important. Learn how to read graphs and charts and statistics. Improve your information literacy: Learn how to find credible sources, how to judge the credibility of a source, and what “credible” actually means. It doesn’t mean infallible.

As a general rule, don’t accept a fact until you have multiple credible confirmations of it. That might not be possible, but when information comes from untrustworthy sources, remember that. Learn the difference between something that you’ve learned and accepted and something that you’ve just heard on social media a few dozen times. This is easier when you have an understanding of what you’re learning. True things fit in better with other true things.

Don’t assume things are false just because the source isn’t credible, either. Just do extra research to verify. Do your own experiments to confirm, if possible.

Sometimes you’ll realize something you’ve accepted might be wrong, possibly because it conflicts with something else that you learned. When facts don’t add up, challenge them. You’re not infallible. Replacing a fact you accepted long ago isn’t a failure; it’s a victory. Many people are incapable of doing so.

Learn to distinguish between facts, inferences, theories, and opinions. (Note that established, accepted scientific theories often fall into the “fact” category.) Facts are verifiable. Inferences are based on facts; they’re evidence-based conclusions that can help to build theories. Theories are explanations, and they can be disproven but haven’t been proven (else they would be facts). Information presented as facts can be false. Theories and inferences can be poorly formed, even if the facts are sound (and especially when they are not). “Opinion” is a word people use to defend flawed theories. If the opinion isn’t a preference, there’s a good chance it isn’t an opinion at all and is just intentional misinformation. “You can’t argue with my opinion” isn’t applicable when the “opinion” is provably false - then it’s just a failed fact, inference, or theory. And even when it is an opinion, it can still be criticized.

Learn about logical fallacies. Even if you don’t call out the person using them, try to notice them in the wild, both by people you agree with and people you disagree with. But especially by people you agree with. Learn how to notice other ways people are misled.