Double Blind Passwords (aka Horcruxing)

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Before we get into Horcruxing, here's a quick prologue on online security hygiene. You can skip to the Horcruxing section if it seems redundant.

Rules for Strong Online Security

1. Longer passwords (atleast 16 characters) are better than shorter ones

=> cutesamantha15101995 > cutesamantha

2. Randomized passwords are better than personally identifiable passwords

=> process-cancel-stingy-garnet > cutesamantha15101995

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

3. Have a significantly different password for each account

Having the same password for different accounts is like using the same key for different locks. It beats the whole point of having multiple locks! Also, having different passwords but with only one easily guessable word different (like the ones below) still poses the same risk. The passwords should be significantly different.

bounce-unfold-stunning-chute        process-cancel-stingy-facebook
symptom-untouched-unpaid-arena  >   process-cancel-stingy-twitter
sediment-tweak-annually-koala       process-cancel-stingy-gmail

4. Use 2FA/MFA wherever possible

Both Google and Facebook offer a 2FA feature where you need the second factor only when you login from a new device or a new location, instead of needing 2FA every time. That's a rare combination of convenience & security right there! Most other sites also offer some variation of 2FA.

NOTE: Use the andOTP (or any other) app's TOTP as the second factor since it cannot be spoofed or spied on lock-screen like the SMS OTP and does not require a mobile network or internet connection. You can also use Biometrics (finger print or face recognition)

Woah! How do I create a long password for each of the bazillion websites out there, and have them significantly different and remember them? Security seems like such a pain in the ass!


A password manager helps you manage all your passwords in one place, either in the form of a browser extension, mobile app, or website. Good password managers will offer a browser extension and a mobile app with one-click auto-fill-login-page feature by removing the hassle of copy pasting or typing your login details. A few smart ones even detect phishing pages and warn you indirectly, by not showing the login details for such web pages.

They enable all the above measures for strong online security with ease. While I agree it takes some effort to set it up for the very first time. But, after that, it just flows like butter.

For example, password generator in BitWarden lets you custom design your random password in different flavours.

BitWarden's password generator

YAY! I'm Secure!

You meticulously move all your passwords and secrets to a trusted password manager. Finally, you can rest easy knowing that your digital life is truly secure. Or, is it?

What if
  • your master password (the password to your password manager) is compromised due to a security breach or you left it in plaintext on a post-it/ email/ notes app
  • someone gained temporary access to your unlocked system (computer or phone) when you stepped away to get that last coffee for the day and your password manager is still logged in for everyone to see

The answer: you're screwed. The cost of putting all your eggs in one basket is that it could all go into oblivion in one fell swoop. How do you overcome this challenge now?

Double Blind Passwords (aka Horcruxing)

For all his faults, Voldemort did one good thing for us muggles. He gave us the concept of a horcrux. For the uninitiated, a horcrux is any object in which you store a piece of your soul, putting the proverbial eggs of your soul into different baskets, to gain quasi-immortality.

The basic idea: You split your password into 2 parts - one which is stored in the password manager, and the other which is stored in your head (aka horcrux).

Basically, at any given point in time, you and your password manager know only a piece of the password. It's double-blind. In effect, just like You-Know-Who, you're splitting your password (soul) into pieces and storing them in different places.


# As stored in the password manager
username: rick
password: rollthepeople1732

# Actual credentials
username: rick
password: rollthepeople1732


# As stored in the password manager
username: rick
password: roll-the-people-venus

# As stored in your head
horcrux: papel

# Actual credentials
username: rick
password: roll-the-people-venuspapel

The horcrux adds an additional layer of security that only you can unlock. It's a kind of 2FA. Again, the longer the horcrux the better. But, a simple word should also be fine as long as only you know the horcrux.

If it feels like too much effort, use a horcrux only for the most important logins - your social media, bank accounts etc.

One Last Thing

Security is never absolute. One can try to secure a system as tightly as possible, but never really say that it is fully secure (if you see someone claiming otherwise, it's mostly marketing bullshit). If we cannot make systems completely secure, the next best thing to do is to make them as secure as possible and a good way to do it is Defense In Depth - basically make sure that even if one layer of security is breached, there exist other layers to mitigate further damage - which is what we've tried to achieve all along.


1. Use a good password manager

I use BitWarden (since it is open source and costs just $10 a year for the PRO features)

2. Use TOTP/ biometrics instead of SMS-based OTP

I use andOTP (since it is open source)

3. Use a horcrux (a double-blind password) for the most important logins

P.S. Keep in mind that horcruxing only works fine until you connect your brain to NeuraLink and accidentally upload your thoughts online for everyone to see. :P

Jérémy Basso's photo

Came for the Harry Potter reference, stayed for the content. Great article ! I use this approach when allocating secrets to users : the secret is a mix of a unique secret in database per user, and a environment secret shared by all users. This way if one of the source is compromised my secrets remains safe.

The "2FA with my head" looks very interesting to me.

On a side note, the risk of using only one Horcrux is that if 2 of your passwords gets compromised, your Horcrux gets slayed by Basilik Venom (because that's an easy catch). Somehow Voldemort was ahead of us in muggles in terms of security with the powerful choice of 7 Horcrux.

Phani Karan's photo

Haha, Lord Voldemort was way ahead of his time, even without a time turner! :P

Yeah, the risk of using only one Horcrux exists. I guess one can create as many Horcruxes as their memory permits, but one still beats zero.

Chris Bongers's photo

This Horcrux password is new to me, so did I get it right, you'll have your password auto-filled by 1password (or whatever) and then typo your addition to it (which was stored in your head)?

I use the following at the moment: 1Password (Master pass only in my head, very long and random) All passwords generated and unique 2FA for all-important apps with G2FA

To me, that seemed pretty solid because even if you'd get my 1Password you couldn't really get into the important part.

Phani Karan's photo

Hey Chris

Yeah, you understood it right. The horcrux (stored in your head) is effectively a second factor.

Your password + 2FA usage is pretty secure IMHO. You can probably use a horcrux for websites that don't offer 2FA, or use it as a third factor for websites which do offer 2FA (3FA might seem a bit too much but to each his own I guess :)

AJ Henderson's photo

Phani Karan Well it's also not adding a factor. 2 passwords is not 2FA. It has to be 2 different factors. A master password for a password manager and a mini-password are still just different version of "what you know" and are just a slightly more complicated single factor.

Prashanthi's photo

Very good idea. Best solution for my password management. I am gonna implement it.

Show +1 replies
Phani Karan's photo

Thanks Prashanthi! :)

Phani Karan's photo

Thanks ranjith Guduru :) I'd suggest you try out BitWarden or any other open source password manager. I liked the UI/UX of BitWarden over LastPass tbh. And there's a simple way to export all your passwords from LastPass to BitWarden.

Szymon Adamiak's photo

That is such a good title I had to click :) Great job!

Phani Karan's photo

Thanks Szymon :)

S Vempati's photo

This was such a fun read! All I gotta do now is change only every password of mine.

Phani Karan's photo

Haha, thanks! Make the passwords long & strong, you must.

May the horcrux be with you :)

Molly Dodge's photo

Terrific job - well explained for someone not as familiar with password standards. Hope to read more of your posts!

Phani Karan's photo

Thank you, Molly :)

David's photo

So this is great but... I have left a sealed envelope for my wife in case I violate Rule #1 ("No dying!")

I would have to put my horcrux in there, which renders it pretty useless as such.


Phani Karan's photo

I wouldn't say it is totally useless as long as it is sealed and stored in a secure place - your wife's password manager, a physical vault (many people use this to actually store their private keys), or your wife could commit it to memory.

The core idea is to keep adding as many layers of security as possible without inconveniencing you/your wife much.

Appaji's photo

Multiple levels of security is a good suggestion and a layman can adhere to the new rules of securing personal information. Appreciated for the quick education to the new bees.

Phani Karan's photo

Thanks Appaji :)

sridhar katta's photo

Phani KaranI use one password for password management, it works great and it also works great with the two-factor authorization for GitHub or any other site which supports 2FA.

Phani Karan's photo

Hey Sridhar

The horcrux is effectively a second factor to your password, especially when the website doesn't offer the regular 2FA.

vaibhav kumar's photo

Very well explained.

Phani Karan's photo

Thank you, Vaibhav :)

Damien Murphy's photo

Makes sense, reduces the possibility of the password manager being a single point of failure.

Also today I learned I can use a passphrase in bitwarden :-)

Srinivas Kagitapu's photo

This is cool Phani, I have an add-on technic for it. Use a fixed number like 4 or 5 along with Horcrux.After the password manager fills the password enter left-arrow 4-5 times (the fixed number that you have in mind) and start entering the Horcrux. You need to remember the number+Horcrux. Some of my colleagues were using it, I felt it super cool. Just incase anyone likes it. 2FA is a must these days BTW.

James Bartlett's photo

Cool! I have an add on to your add on, instead of pressing the left key 4-5 times before entering the ‘horcrux’ - how about replacing part of the stored password? Eg, the first or last 4 characters?

Joseph's photo

I had a related idea of how to do encrypted messaging:

Show +4 replies
AJ Henderson's photo

Joseph But it doesn't fix it. Even if offline, if the NSA has put a pattern in to the CNG of Windows for example and you use the randomness from that machine, they may be able to defeat it and thus defeat your one time pad.

Granted, you might be able to get around this by having multiple systems work together to form the one time pad, all offline.

Joseph's photo

AJ Henderson

Please read the website. I already say the hardware should have a good random (ideally hw source) source of randomness.

Priyank Gupta's photo

While it is great advice/suggestion. Here is a catch that should be carefully considered. You can't have too many Horcrux phrases. Using the same one across all websites means that when a website handles your data irresponsibly and is leaked to hackers/unintended-users, then the phrase is ousted immediately and rendered useless (and leaving you under a false sense of security). So Horcruxes need to be used selectively. Not on websites that don't offer 2FA, but on websites/services where you trust them to handle your data responsibly. for example using the same Horcrux for a food delivery app and a banking app is a bad idea. They don't do the same threat modeling and possibly don't look at data privacy and security with the same lense.

Paul Serdiuk's photo

This is exactly like salting hashes before storing them in a DB, quite clever.

AJ Henderson's photo

Except that salting is only intended to make the use of rainbow tables inefficient. It doesn't add a security benefit beyond making it harder to attack an individual password. In this case, it's more accurate to say that in the compromised password DB scenario, this provides a very weak password as a protection against the main password being converted to effectively being a salt.

Unfortunately, that's not likely to do much if someone has both a compromised hash table and your main password and the simple "horcrux" would rapidly be found by brute force hashing given it is short and rememberable.

Dave's photo

See - "Horcrux: A Password Manager for Paranoids".

AJ Henderson's photo

I'm not seeing what this adds. This is the same thing as putting up 2 passwords and calling it 2FA (which it isn't). Under the vast majority of threat cases I can think of, you are either still screwed because they capture your login at the same time they capture your master password or you are stuck back with the problem of remembering a secure, non-guessable element for every account, which is exactly why password managers exist in the first place.

This is either ineffective, impractical or both depending on the threat you are trying to protect against. It's also trying to solve a problem that was already solved. This is exactly the reasoning behind 2FA/MFA and making sure that access to multiple things is needed.

It would be much better to get a Yubikey or similar and put your HOTP/TOTP secrets in to that so that it is physically isolated from your phone and the internet and thus can't be compromised without direct theft of multiple devices. You get the same advantages without the disadvantages and limitations of hanging your security on two of the same factor.

R. M.'s photo

This is good advice, and in fact I make and sell a line of offline password generator/recall rings, key fobs, bracelets and cards which help to do exactly this:

The advantage to these is that they are not software which can be hacked like password wallets, being completely offline.

Show +1 replies
R. M.'s photo

AJ Henderson As you correctly point out, just having a scheme to create randomness, plus a mentally-remembered 'horcrux' isn't 2FA. It serves only to keep full passwords from residing in one place.

My widgets were specifically created for people who are techno-phobic, who in my experience were resistant to using any sort of software wallet solution -- at least it gets them to stop using the same password or a trivial variant thereof, across all their accounts...

As always, defense-in-depth is important; each measure can serve to incrementally improve security.

AJ Henderson's photo

R. M. yeah, to be clear, I think your devices are a good idea. My point was mostly that this original post isn't really that useful of an idea. Much better to harden the password storage instead, which is exactly what an offline device does for you.

Ridhik Govind's photo

Okay so I have been using this method of making my own extra word, remembering it and adding it to password for sometime now and its been great. But honestly, I never knew this was "actually" a method that was used to give passwords an additional layer of security until I read this article. What an amazing article !