For a trade secret to exist, there must be novelty, secrecy and value to the owner's business. Under some laws, it is a criminal offense to take or use another's trade secret without permission. A trade secret exists as long as it is kept a secret. An effort must be made to keep the trade secret. If a person is told the secret and there is no confidential relationship, property rights in the secret can be lost.
Most companies have employees sign an Employee Agreement when they are hired.
This agreement and state and federal laws obligate the employee to keep confidential company information in confidence. The employee cannot legally go to another employer and use or disclose confidential lists of his or her former employer's customers, its confidential business practices, its confidential marketing plans, its confidential technology, etc. If a patentable invention is kept as a trade secret, there is a risk that a later inventor might obtain a patent on the same invention. The fact that a secret product or process is used commercially does not prevent the issuance of a patent to another party and is not grounds for invalidating the patent. Under U.S. patent laws, the patent would be infringed by the prior secret user and such user could be forced either to stop using the patented invention or to pay a royalty to use the invention.