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Double Blind Passwords a.k.a. Horcruxing

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Re: Double Blind Passwords a.k.a. Horcruxing

#51

Post by nucleardog »

GekkePrutser wrote: post #21

I do't really agree with the long passphrase thing.. I leave my passwords at 12 characters max (and 8 for less important sites) Reason: You still have to type it sometimes. Like on a device you don't have the password manager on. That makes it really annoying. And because it's only used on one site it doesn't really matter how long it is. If a hacker gets hold of the password file they already own that site anyway. D…

> Reason: You still have to type it sometimes. Like on a device you don't have the password manager on.

Assuming a standard typeable character set (letters upper/lower, numbers, symbols you can type on a standard US keyboard), you've got 92 characters. (Safe assumption given you're planning on typing this on all sorts of devices.)

Your randomized eight character password has 52 bits of entropy. Twelve characters takes it it to 78 bits. Not really enough if you're up against an offline attack.

Assuming you choose 5 random English words (which will probably take you about two seconds to type on something like a phone), you'll have a more secure password.

I agree typing on devices that don't have your password manager is annoying, but in my experience it _really_ doesn't come up that often. Yours is the exact reason I use 32 character passwords rather than the 64/128/etc some people I know use.

But 12 is.. short. The trade-off between the added security and the inconvenience makes it a pretty obvious choice for me. (And you're wrong--having a database dump full of password hashes does not "already owning that site" make.)

Typing 32 characters on a game console to log into Netflix taking an extra minute every few years is really not that inconvenient relative to the added security. And it's something like 2^130 times more secure than your 12 character password for the inconvenience it brings. Or about 1,361,129,500,000,000,000,000,000,000,000,000,000,000 times (I can't actually find the SI prefix for how big this is) stronger.

Re: Double Blind Passwords a.k.a. Horcruxing

#52

Post by lstamour »

GoblinSlayer wrote: post #44
Thorrez wrote: post #32

Earlier quoted context omitted.

I had one of the most valuable accounts in a video game, so attackers of all kinds were constantly contacting me. I was immediately suspicious of anyone who contacted me. I signed up for the forum with a password from my password manager (I like toying with attackers). I told him I signed up, and a few minutes later he said there was a problem with my account and asked if I used a password manager. I said yes. He sai…

All security eventually relies on obscurity, it's a bad idea to disclose your security practices. Use hunter2 as password for junk sites.

By that same logic, use disposable email addresses and the password doesn’t matter? I mean, this kind of thing only holds up while you don’t care to enter any data about yourself and re-visit the site later. Those who need to be anonymous can provide junk info to junk sites, sure, but for everything else, there’s email and 2FA TOTP codes and password managers for a reason... largely because OAuth and FIDO2 aren’t universal yet I suppose ;-)

Re: Double Blind Passwords a.k.a. Horcruxing

#53

Post by blueblisters »

29athrowaway wrote: post #45

> NOTE: process-cancel-stingy-garnet is technically a passphrase - basically an easy-to-remember password in comparison to randomized strings like B6fSpxMj&f6DU@5^k (Word dictionary size)^4 > (Alphabet size)^17 I don't think so

With a dictionary of 10k words, you can get 1e16 combinations, which seems adequate when used with a deliberately slow hash function like bcrypt.

Re: Double Blind Passwords a.k.a. Horcruxing

#54

Post by TacoSteemers »

gulbrandr wrote: post #36
mjevans wrote: post #3

I don't like raid-0 for passwords.

What do you mean?

They probably mean that they don't like situations where the loss of one password element / harddisk means losing everything.

In other words: they don't like having a single point of failure.

Re: Double Blind Passwords a.k.a. Horcruxing

#56

Post by boomboomsubban »

GoblinSlayer wrote: post #42
Thorrez wrote: post #28

If there's generic malware that's targeting your password manager, then yes this provides protection against that. But it doesn't provide protection against a targeted attack, because the malware can just keylog your horcrux. Another weakness that doesn't require a keylogger, is the attacker might be able to find some stolen database of a website that stored passwords in plaintext, then deduce your horcrux from the d…

>And if no password databases are available, the attacker can create a website and ask you to join it under the hope you'll reuse your horcrux on the attacker's site. Some sites email your password to you: https://plaintextoffenders.com/

It's sad to think that the list of 5801 sites probably only accounts for a couple percent of the total amount of offenders.

Re: Double Blind Passwords a.k.a. Horcruxing

#57

Post by Dylan16807 »

war1025 wrote: post #10
emmanueloga_ wrote: post #7

This is a cool/useful idea. I thought the article was gonna be about "Shamir's Secret Sharing" [1], "where a secret is divided into parts, giving each participant its own unique part. To reconstruct the original secret, a minimum number of parts is required.". Sounds horcruxy to me :-p. I learnt about it from the PIM book [2]. 1: https://en.wikipedia.org/wiki/Shamir%27s_Secret_Sharing 2: https://pimbook.org/

I thought that algorithm was crazy magic when I first heard of it. The method behind it is pretty fascinating. A nth degree polynomial is uniquely identified by n+1 points. So the algorithm interprets your secret to a binary numeric value, sets that as the value at x=0 (i.e. the constant term of the polynomial), picks random coefficients for all the polynomial degrees, then computes coordinate pairs for however many…

While it's a clever method, it's also worth noting that for moderately-sized groups you can achieve the same thing with a much simpler method and almost no math.

Let's say you have a 256 bit key as the secret, and you want any 5 out of 15 people to have access.

For each combination of 5 people, pick 4 random 256 bit numbers. 4 people get those and 1 gets the key encrypted with those numbers as a one time pad.

Once you do every combination, each person will end up with a list of a thousand numbers. Any 5 of them can get together, each grab their number for that group, and XOR them to access the secret.

That's only 32KB of data to hang onto. With 15 people the absolute max is 107KB. Even printed as plain text it would need less than 20 sheets of paper.

Re: Double Blind Passwords a.k.a. Horcruxing

#58

Post by vinay_ys »

tobib wrote: post #17
vinay_ys wrote: post #11

It is much better to use a password manager than trying to remember poorly crafted passwords in your head. But also really/truly remember not to really put all your eggs in one proverbial basket. Password managers are not without dangers: 1. If you forget your master password or secret key (you need both to setup a new device), you are screwed. 2. If the password manager cloud sync service (like 1password) decides to…

> 4. If your password manager logs your sign-in access patterns along with your IP addresses (even from behind your fancy VPNs), you are screwed. Can you explain why one would be screwed in this case?

In this case, screwed w.r.t privacy (your credentials may still be safe). But you may become a target because of your sign-in activities which are no longer private.

Re: Double Blind Passwords a.k.a. Horcruxing

#59

Post by TwoBit »

Thorrez wrote: post #28

If there's generic malware that's targeting your password manager, then yes this provides protection against that. But it doesn't provide protection against a targeted attack, because the malware can just keylog your horcrux. Another weakness that doesn't require a keylogger, is the attacker might be able to find some stolen database of a website that stored passwords in plaintext, then deduce your horcrux from the d…

> attacker can create a website and ask you to join it under the hope you'll reuse your horcrux on the attacker's site.

I don't think that reusing the same pepper (horcrux string) for all sites would be best practice.

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