First of all, if you develop software yourself and have sold it normally, the authorship rights of this software already belong to you. "Unless otherwise provided by laws and administrative regulations, software copyright belongs to the software developer. If there is no proof to the contrary, the natural person, legal person or other organization who signs the software is the developer." So of course you enjoy the copyright.
Secondly, the licensed use of software copyright: "The licensee shall not exercise the rights that are not expressly granted by the software copyright owner (that is, you) in the license contract." So your three questions are easily solved. , as long as you do not grant him the right to publish or distribute in the licensing contract, the other party cannot register or resell it.
Copyright use contracts generally include the following main contents: (1) Types of licensed rights, including exclusive use rights and non-exclusive use rights. If the user obtains the exclusive right to use the work, he or she has the right to exclude all others, including the copyright owner, from using the work in the same manner. So this is what you need to pay attention to. If you want to continue selling this software, you must not grant him exclusive use rights. (2) The geographical scope and period of licensed use (3) Payment standards and methods (4) Liability for breach of contract (5) Others
I will give you two additional reminders: (1) If you have not entered into a written If the contract or the contract does not expressly stipulate an exclusive license, the rights to be exercised by the license shall be regarded as non-exclusive rights. In other words, after you sign a non-exclusive license contract with him, you can also sign such a non-exclusive license contract with someone else. It cannot prevent you from transferring your software to several people at the same time.
(2) If he publishes, registers, modifies, translates, copies or partially copies, distributes, rents, deletes, changes, transfers, or permits others to use your software without your permission, it is Infringement of your copyright. You can request the people's court to require the other party to bear civil responsibilities such as stopping the damage, eliminating the impact, making an apology, and compensating for losses.