This is perhaps a very newbie question but I can't find a definitive answer, so hence my question.
My theoretical scenario.
An organisation has a PKI CA with a very low key strength, say for example 1024 bits
The decadents such as the users registered from the CA have a higher key strength of 2048 bit and each have a physical ID file which contains information of their public key and the key identifier of the CA that issued their ID,
An attacker has managed to steal the user's ID even if the user's original ID was recreated/re-certified would the lower encryption of the CA allow the attacker find enough information to help compromise the CA even in theory?
Thanks in advance for all replies