I have advocated for bcrypt many time specifically for this. If you can't deploy bcrypt, enforce an upper limit in your authentication form. 100 characters is stupidly more than enough, even for long passphrases.
https://instatunnel.my/blog/the-1mb-password-crashing-backends-via-hashing-exhaustion
@atoponce That's an AI vibe coded company and that article has massive errors besides hallucinating the whole issue. Since none of those algorithms (properly implemented) can DoS. Here's a fun vulnerability they created:
> 1. User sends a 1MB password.
> 2. Server computes `temp_hash = SHA-256(password)`.
> 3. The output of SHA-256 is always a fixed 32-byte string.
> 4. Server computes `final_hash = Bcrypt(temp_hash)`.
In PHP, this is broken because of C strings in the library that does bcrypt.
P.S. The contact page has this:
> InstaTunnel Inc.
> 123 Tech Street
> Suite 100
> San Francisco, CA 94105
> United States
> Phone: +1 (555) 123-4567
Aaron Toponce ⚛️
Sc00bz