Why every TOTP app default uses SHA-1 hash encryption? (lemmy.world)

submitted 4 months ago by PrivacyWayFinder@lemmy.world to c/privacy@lemmy.ml

11 comments fedilink hide all child comments

I use Aegis as my 2fa. Today on new token creation I observed that there's hash function set to SHA-1, later checked all my tokens and the result is same type of encryption used for all. So I have edited all my tokens to SHA-256 as a result my totp doesn't authenticate. Do I have to rescan my tokens for updating to SHA-256 or it doesn't work like that?

Security: SHA-1 < SHA-256 < SHA-512

Speed: SHA-1 > SHA-256 > SHA-512

My doubts are: Why can't we use SHA-256? Is it because TOTP requires less time so faster one(SHA-1) is chosen? Can we use SHA-256 for TOTPs?

you are viewing a single comment's thread
view the rest of the comments

[-] RvTV95XBeo@sh.itjust.works 10 points 4 months ago

capture the generated codes and time of input in some way, then brute force hashes until they generate one that produces the correct codes at x time

Given a TOTP key is usually at least 18 characters for a 6-digit code, having only one data point sticks you with something on the order of 10^28 possible keys for a given singular code (way more if case sensitive). You'd need to be regularly intercepting TOTP codes to brute force your way to the right key, and even then it'd only be valid for a single site. At that point it probably means you've fully compromised the connecting device or server, at which point, why do you even need the TOTP again?

this post was submitted on 07 May 2024

41 points (97.7% liked)

Privacy

31258 readers

453 users here now

A place to discuss privacy and freedom in the digital world.

Privacy has become a very important issue in modern society, with companies and governments constantly abusing their power, more and more people are waking up to the importance of digital privacy.

In this community everyone is welcome to post links and discuss topics related to privacy.

Some Rules

Posting a link to a website containing tracking isn't great, if contents of the website are behind a paywall maybe copy them into the post
Don't promote proprietary software
Try to keep things on topic
If you have a question, please try searching for previous discussions, maybe it has already been answered
Reposts are fine, but should have at least a couple of weeks in between so that the post can reach a new audience
Be nice :)

Related communities

Chat rooms

[Matrix/Element]Dead
Discord

much thanks to @gary_host_laptop for the logo design :)

founded 4 years ago

MODERATORS