I wrote some software as part of an internship. It worked well for the task and we published a paper on it. However, because the internship was at a company, not my graduate institution, the code is technically property of the company and they do not want to release it. I've received several requests for the code, and I know that releasing the software will increase my paper's citations and impact. Is it okay to re-implement the code I wrote and release it as open source, or could that violate some laws or policies?
For the record, when I say re-implement, I mean start from scratch, not reuse most of the same code and change a few things.