a clean room implementation means that the person writing the code does not have acess to the code they're trying to replicate. Even when the source is availab

a clean room implementation means that the person writing the code does not have acess to the code they're trying to replicate. Even when the source is available, it is looked at by people, who write requirements based on what they observed in the code. After that, they are considered compromised, and are banned from ever touching the code of the re-implementation.