Re:The Catch 22 of Base64: Attacker Dilemma from a Defender ...
by zrm on Tuesday May 01, 2018 @03:04PM
(#16970306)
> based on the assumption that legitimate users have no practical need to do multiple encoding of the same text.
Things can legitimately be encoded multiple times because encapsulation is a thing and multiple independent stages may each be configured to accept possibly binary input and produce base64 output.
You also don't need to re-encode something an unreasonable number of times to get "Vm0wd", all you have to do is start with "Vm0" and base64 encode it twice. "Vm0" only has 24 bits of entropy which means it will regularly occur at random in legitimate data.
And then nobody can figure out why "Vm0-Edge-West" isn't working.
Things can legitimately be encoded multiple times because encapsulation is a thing and multiple independent stages may each be configured to accept possibly binary input and produce base64 output.
You also don't need to re-encode something an unreasonable number of times to get "Vm0wd", all you have to do is start with "Vm0" and base64 encode it twice. "Vm0" only has 24 bits of entropy which means it will regularly occur at random in legitimate data.
And then nobody can figure out why "Vm0-Edge-West" isn't working.