These numbers are very rough estimates but give an idea of what length of passphrase a very powerful adversary like a state-sponsored attacker could guess.

Even if guessing a passphrase of 3 random words with LUKS1 costs very little energy, any such attack also requires:

- Physical access to the device - Very expensive computer equipment - Professional hacking skills

You can see the details of our calculations in [[!tails_ticket 19615]] and this [spreadsheet](https://cryptpad.disroot.org/sheet/#/2/sheet/view/KdOJLeuCsc4dS3vq-bHhFw6zByUSRJXsCcAkB-ERxtc/).

<h2 id="schemes">Other password schemes give too little guarantee</h2>

We recommend using passphrases made of several random words because using randomness is the only way to really guarantee the strength of a password.

Using other password schemes give little guarantee over the strength of a password, even if it follows complicated password policies and validates on password strength meters.

For example, a [Dutch hacker logged into Donald Trump's Twitter account *twice*](https://www.washingtonpost.com/world/2020/12/17/dutch-trump-twitter-password-hack/) by guessing his passwords, despite that these passwords included several words, were more than 8 characters, and even had special characters. They were definitely not random enough: "*maga2020!*" and "*yourefired*".

To understand the maths behind password strength, watch [An information theoretic model of privacy and security metrics](https://media.libreplanet.org/u/libreplanet/m/an-information-theoretic-model-of-privacy-and-security-metrics/). Bill Budington from the EFF explains the concept of entropy and its implication on browser fingerprinting and password safety in accessible terms.

<h1 id="updating">Keeping your encryption secure</h1>

All users are recommended to upgrade to LUKS2 on all their encrypted devices: Persistent Storage, backup Tails, and other external encrypted volumes.

Depending on the strength of your passphrase, we might also recommend choosing a different passphrase and migrating to another Tails USB stick:

- [[If your passphrase has 4 random words or fewer|argon2id#4]] - [[If your passphrase has 5 random words|argon2id#5]] - [[If your passphrase has 6 random words or more|argon2id#6]]

<h2 id="4">If your passphrase has 4 random words or fewer</h2>

If your current passphrase has 4 random words or fewer:

- Your encryption is insecure with LUKS1.

You have to upgrade to LUKS2.

- Your encryption is more secure with LUKS2.

We still recommend changing your passphrase to be 5 random words or more.

Persistent Storage (4 words or fewer)

Persistent Storage (4 words or fewer)