Until such time as the information learned becomes

Until such time as the information learned becomes public knowledge.
As examples: if a contract were to be involved the NDA would expire when the contract was reveled publicly. Also,my understanding would be no buying or selling of stock would be allowed during that time.
In the case of a trade secret such as a manufacturing process,or a proprietary formula ( as in Coca-cola) it could be forever. Stock trading would not be effected in that case.