The essential characteristics of legal punishment are it must be oppressive and condemnation to the person who committed a crime. There are different kinds of how severe legal punishments to a criminal in every country but mostly follow these two characteristics. An example is a person must be condemned that he or she really did a crime to a person or to his or her country. They should not be punished until a judge passes them guilty.
Then that person will be oppressed to pay off his or her crime by his freedom. He or she is free to live but inside the metal gates being watched by policemen. They will live a life following a routine and a minimal chance to get outside the jail and live like a normal, innocent civilian.
Legal punishment must follow legal rules of some sort. It is authorized by a legal entity and follows a set of rules that establish who is to be punished, how, and how much.