# What is the current security level of an algorithm?

I was reading a paper of some years ago about a cryptography and a phrase got my attention.

We want to ensure a security level of at least $$2^{80}$$

I know that $$2^{80}$$ was used as rule of thumb rule, that's probably why they wrote that sentence.

But reading this I think that $$2^{100}$$ may also be too low. Considering for example the resource that a state like US can have what is a reasonable security level?

EDIT: I'm considering only the security level for a bruteforce attack, other algorithm can have a solution that require less computational force.

• keylength.com documents what various people consider to be an appropriate security level.
– SEJPM
Apr 24 '20 at 14:25
• @SEJPM so reading from the NIST, 2**120 can be used as thumb rule for a bruteforce attack right? Apr 24 '20 at 14:50
• NIST basically says 112 bits through 2023, then transition to 128-bit, with 112 no longer being allowed by 2030 Sep 21 '20 at 17:38