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Entropy isn't sufficient to measure password strength

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Re: Entropy isn't sufficient to measure password strength

#91

Post by nybble41 »

GoblinSlayer wrote: post #53
Zamicol wrote: post #32

Earlier quoted context omitted.

The point of public key cryptography is that there isn't a shared secret.

A shared secret is not an attack vector though, a reused secret is. If you reuse an asymmetric key, it will identify you across the world. But if you don't reuse an asymmetric key, then the point of asymmetric cryptography is moot and is no better than a password manager.

Using something like the Hierarchical Deterministic approach used for modern cryptocurrency wallets ("HD wallets") you can reuse a single master asymmetric key for any number of logins without linking those logins together.

In this scheme there is a single master private key which you protect in whatever way seems best and never share with anyone. From this master private key you can derive any number of subordinate private keys, each with its own public key. You share one of those public keys with each service, along with the derivation path, and authenticate using the corresponding private key. Only the unchanging master private key needs to be stored, so unlike a password manager there is no need to make new backups or sync a password database across multiple devices when you set up a new account. Best of all, without either the master private key or the corresponding master public key there is no (known) way to show that any two subordinate keys were derived from the same master key—they appear unrelated.

Re: Entropy isn't sufficient to measure password strength

#92

Post by bigiain »

aeternum wrote: post #86
awelxtr wrote: post #43

Earlier quoted context omitted.

> A lot of people (do not trust password managers, case in point the recent last pass scare. That's no excuse. KeePass allows having the database file locally where it's you duty to manage it. It might be less convenient, maybe. But I don't see valid excuses for people to not start using a password manager, even less the less tech savvy people.

Keeping a local database file secret is a pretty difficult task. You introduce a wider attack surface vs. a memory-based password.

Keeping it secret isn't as critical as you make it sound.

KeePass is open source. You can review the crypto, or pay somebody competent to review the crypto, or trust that the project or some 3rd party has done so.

I wouldn't go out of my way to publish my KeePass file publicly, but any attacker who can break the 256 bit AES encryption, or brute-force/dictionary-attack it's key that's using Argon2 KDF with enough rounds to take 1 second per key transform on my laptop, is well into the "I stand no chance against state level actors specifically targeting me" category, and I'll just assume I've lost to them already. In the immortal words of James Mickens: "If your adversary is the Mossad, YOU'RE GONNA DIE AND THERE'S NOTHING THAT YOU CAN DO ABOUT IT." If ASIO/CSIS/GCHQ/GCSB/NSA want access to my accounts, it's unlikely having passwords that are only in my memory is going to make much difference to my personal outcome. If a driveby teenaged script kiddie hits a zero day on one of my devices and pops my KeePass file, I'm not even sure I'd bother changing the passwords.

I'm happy enough storing the KeePass file on my (encrypted) laptop hard drives. I'm OK with using iCloud to sync it to my phone. I'm fine with it being part of my regular TimeMachine backups to a pair of external usb (encrypted) drives, and for a copy of that usb drive backup to be synced to an encrypted S3 bucket.

Re: Entropy isn't sufficient to measure password strength

#93

Post by dredmorbius »

krupan wrote: post #18

When will we stop using passwords?! They are an elementary school kid “secret club” game taken way, way too far. They are totally broken. Nobody can come up with and remember good passwords. Nobody can store passwords securely. 100% busted. Instead of continuing to debate what makes a good password, we need to put our energy into better techniques altogether! No more shared secrets! Let’s talk about one-time codes, a…

PKI and physical tokens, preferably not involving plugging into any ports (NFC devices) have been my suggestion for most of a decade now.

Passwords were adopted when comuting was something that occurred at a specific facility and the goal was to keep the people, largely the users one already knew of, out of one-another's accounts and data.

The persistence of passwords in a world of global access and billions of devices is ... ludicrous.

And the failure of both enterprises and governments to identify better standards and practices is criminal.

Re: Entropy isn't sufficient to measure password strength

#94

Post by bigiain »

taeric wrote: post #22
bigiain wrote: post #12

> Because choosing good passwords is about memorableness as well as sheer strength That's not been true ever since the development of good password managers. There are fewer than 10 passwords I remember. One of them is my password manager's master passphrase (5 misspelled-and-with-random-punctuation words). The others include stuff like my work and home laptop/disk passwords, which I can't autofill, my 3 important ba…

I'm curious if you have a rotation/audit practice for those? With 600 odd passwords, I'm not even sure how I would keep track of access to the items being protected.

Rotating/expiring random 25 char passwords is unnecessary.

One big advantage of a password manager is you _can_ audit accounts/passwords. I do a once a year sweep of my personal ones in KeePass, and use it as an opportunity to close accounts on services I no longer use. (Not that I believe any 3rd party service can be trusted to actually delete your data when you close your account, but spending 5 minutes updating your profile with junk data before deleting it improves your chances of not ending up on spam lists or automated credential stuffing attacks when that service gets popped.)

For the work shared passwords we use 1Password, which while I prefer their old standalone app over their new cloud thing, they do two very useful things - 1) integrate with HIBP's password checking service so it warns you when you have a password that's been published in a dump, and 2) provides an audit trail of which credentials each team member has ever accessed, so you can revoke only what's needed instead of rolling all shared passwords every time a staff member leaves.

Re: Entropy isn't sufficient to measure password strength

#95

Post by krupan »

BeFlatXIII wrote: post #71
mojuba wrote: post #23

Earlier quoted context omitted.

In one of my current web-based projects I decided to experiment with magic links sent via email. They are pretty convenient (and secure enough) but turns out there's a problem with mobile email clients: they tend to open links in isolated embedded browsers and then forget the cookies. For most non-technical people this is a show stopper unfortunately. I then went with one-time 6-digit sign in codes that are emailed t…

Having to check my e-mail for each login is a major annoyance. Perhaps something like SQRL[0] may help. [0]: https://sqrl.grc.com/pages/what_is_sqrl/

More annoying than passwords?

Re: Entropy isn't sufficient to measure password strength

#96

Post by krupan »

kevincox wrote: post #70
mojuba wrote: post #23

Earlier quoted context omitted.

In one of my current web-based projects I decided to experiment with magic links sent via email. They are pretty convenient (and secure enough) but turns out there's a problem with mobile email clients: they tend to open links in isolated embedded browsers and then forget the cookies. For most non-technical people this is a show stopper unfortunately. I then went with one-time 6-digit sign in codes that are emailed t…

I find this way less convienent because my password manager automatically fills in my username and password. So I can log in with 1 click. With "magic links" I need to enter my email (which may be autocompleted, but it is much less reliable) and then wait for the email to show up. (Assuming I have my email available.) Also email is never going to be reliably "instant" spam techniques include bouncing an email and wai…

My experience with password managers is that it works that well on about 10% of websites/apps, and I have to resort to copy and paste from the password manager everywhere else. It's not that great

Re: Entropy isn't sufficient to measure password strength

#97

Post by krupan »

voiper1 wrote: post #34
mojuba wrote: post #23

Earlier quoted context omitted.

In one of my current web-based projects I decided to experiment with magic links sent via email. They are pretty convenient (and secure enough) but turns out there's a problem with mobile email clients: they tend to open links in isolated embedded browsers and then forget the cookies. For most non-technical people this is a show stopper unfortunately. I then went with one-time 6-digit sign in codes that are emailed t…

Sometimes the magic links or codes expires in X minutes. That helps them feel secure. But like password resets, you're hosed if your email is hacked (unless you have 2FA).

So, no worse than passwords at all

Re: Entropy isn't sufficient to measure password strength

#98

Post by krupan »

yosamino wrote: post #39
krupan wrote: post #18

When will we stop using passwords?! They are an elementary school kid “secret club” game taken way, way too far. They are totally broken. Nobody can come up with and remember good passwords. Nobody can store passwords securely. 100% busted. Instead of continuing to debate what makes a good password, we need to put our energy into better techniques altogether! No more shared secrets! Let’s talk about one-time codes, a…

> Nobody can store passwords securely. 100% busted. [...] Let’s talk about > one-time codes One-time codes rely on a password: either it is stored in your 2FA App, or they rely on your email password, or they rely you storing a password somewhere else. OTP rely on stored secrets. You can make these secrets be much larger than the humble password and call them "private keys" : > asymmetric key cryptography, hardware t…

I feel like this whole argument is saying, "these other solutions have problems that somewhat resemble problems that passwords have, so just keep using passwords." Sorry I'm not convinced.

Re: Entropy isn't sufficient to measure password strength

#99

Post by krupan »

taeric wrote: post #26
krupan wrote: post #18

When will we stop using passwords?! They are an elementary school kid “secret club” game taken way, way too far. They are totally broken. Nobody can come up with and remember good passwords. Nobody can store passwords securely. 100% busted. Instead of continuing to debate what makes a good password, we need to put our energy into better techniques altogether! No more shared secrets! Let’s talk about one-time codes, a…

I'm curious how you think these other items work. They ultimately boil down to a shared secret that is beyond what you can remember. Which... isn't the best thing, necessarily. Consider, if I leave my hardware token at home when I go on vacation, I'm basically locked out of all of my accounts. This is fine, as I typically plan for this to be the case. But it is an attack vector. I can't even audit my protected assets…

How is any of that worse than passwords? I only see improvements. Still not perfect, but big improvements.

Re: Entropy isn't sufficient to measure password strength

#100

Post by perryizgr8 »

mojuba wrote: post #23
krupan wrote: post #18

When will we stop using passwords?! They are an elementary school kid “secret club” game taken way, way too far. They are totally broken. Nobody can come up with and remember good passwords. Nobody can store passwords securely. 100% busted. Instead of continuing to debate what makes a good password, we need to put our energy into better techniques altogether! No more shared secrets! Let’s talk about one-time codes, a…

In one of my current web-based projects I decided to experiment with magic links sent via email. They are pretty convenient (and secure enough) but turns out there's a problem with mobile email clients: they tend to open links in isolated embedded browsers and then forget the cookies. For most non-technical people this is a show stopper unfortunately. I then went with one-time 6-digit sign in codes that are emailed t…

> one-time 6-digit sign in codes that are emailed to the user

> I'm wondering if they will feel secure to the users

I don't know about secure, but most users will feel extremely irritated for sure.

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