# How to express difficulty of breaking crypto when writing?

When writing for both technical and non-technical readers I find my self naturally wanting to write things such as :

"..therefore it would be impossible to decrypt the data."

When trying to convey the real world difficulty in breaking AES for example.

My question is, what is the most succinct yet correct term for expressing this, both from a work effort perspective and a side-channel one?.

For a pure work effort perspective :

"Computationally infeasible"

Sounds good, but would not take into account side-channel type attacks.

Any appropriate term would need to be technically correct but strong enough so that non-technical readers understand the risk is extremely low.

Thanks

• I've used lots of terms here; no threat from brute-force, theoretically broken but not practically, have 128-bit security, this implementation is currently safe to known side-channel attacks, ( See BearSSL, which is almost secure against most of the recent attacks :) ). in short the correct word using is really changing who is the audience and what is the attack we are talking, etc. – kelalaka Mar 28 at 16:43
• Probably that's why screen writers prefer to express the difficulty via some graphics like tumbling letters (Matrix) or dissolving screens (Hackers), especially for the non-technical market. And Star Trek handles difficult tech talk with percentage movements. – Paul Uszak Mar 29 at 11:55
• Your last sentence is almost an oxymoron, unless you're looking for strong words like "Giga-flippin' hard". – Paul Uszak Mar 29 at 11:56

Your technical readers will gloss over the example. If you use this try to use fixed pitch for the large numbers.

The technical term is computationally infeasible. But as an example consider the two numbers:

 7,500,000,000,000,000,000
18,446,000,000,000,000,000


The first is 7.5x1018, the second number is somewhat less than 264.

The first number is a reasonable guess of the number of grains on sand on planet earth. The second is the number of different 64-bit numbers. Trying to check each one would take many very fast computers a very long time. But today, doing so is Giga-flippin’n hard but is still possible given a large budget. Please note that adding a single bit doubles the number of possible values.

The minimum key size for AES is 128 bits. That’s 3.4x1038 possible short keys.

There is some concern that quantum computers may someday be able to break AES if only minimum key sizes are used. AES is often used with 256-bit keys.