A trade secret is a piece of information used in business that is an ingredient of a product or key process of a service. A trade secret can be used in any business. It can be used to make a product, or it can be a part of marketing and sales methods. Many companies have their own zealously guarded customer lists, and these are considered trade secrets. The secret is information that is not available to the public. The best way to keep them secret is to limit the amount of people who know about them. Trade secrets have virtually no specific lifespan. As long as they remain secret, they can be secrets for eternity. There is, however, a risk associated with claiming a trade secret. Companies are not allowed to claim copyright or patents rights. In this sense trade secret can be transmitted or sold in international markets through International Technology Transfer Agreements.