If you are talking about a smart-contract being able to do stuff with encrypted data without other people being able to access the data, I don't think this would help with that, because whatever system the contract would use would be available to whoever is trying to get the data from the contract.

Though, things may be enough to make it hard for other contracts to get stuff from a particular contract? I'm somewhat skeptical of that, but maybe. Also, in any case, the "attacker" contract could just make an incentive for people to give it the information, which I think would work. (and that might be necessary for it to get the info from the defending contract anyway? I don't remember. I don't think it is, but I'm not sure.)

However, I'm not sure that is what you meant, and also I'm not sure of what I'm saying.

edit: well, there are other systems that have been designed to let contracts keep information secret but I think those are still too expensive to be used, and relied on a secret sharing scheme iirc, so would require that not all the info be on chain.