<P> A restricted keyblank has a keyway for which a manufacturer has set up a restricted level of sales and distribution . Restricted keys are often protected by patent, which prohibits other manufacturers from making unauthorized productions of the key blank . In many cases, customers must provide proof of ID before a locksmith will cut additional keys using restricted blanks . Some companies, such as Medeco High Security Locks, have keyways that are restricted to having keys cut in the factory only . This is done to ensure the highest amount of security . These days, many restricted keys have special in - laid features, such as magnets, different types of metal, or even small computer chips to prevent duplication . </P> <P> Another way to restrict keys is trademarking the profile of the key . For example, the profile of the key can read the name of the manufacturer . The advantage of a trademark is that the legal protection for a trademark can be longer than the legal protection for a patent . However, usually not all features of the profile are necessary to create a working key . By removing certain unnecessary features, a non restricted profile can be derived, allowing the production and distribution of non restricted key blanks . </P> <P> Keys appear in various symbols and coats of arms, the best - known being that of the Holy See--derived from the phrase in Matthew 16: 19 which promises Saint Peter, in Roman Catholic tradition the first pope, the Keys of Heaven . But this is by no means the only case . Many examples are given on Commons . </P> <P> Among Palestinians, the key is widely used as a symbol of commemoration of the Nakba (the 1948 Palestine war in which Israel was created and hundreds of thousands of Palestinians became refugees). This usage is derived from the fact that many of the Palestinians who became refugees in 1948 had locked their homes when leaving, expecting to return soon, and took the keys with them . Such keys are preserved as family heirlooms in many Palestinian refugee families - even though the house to which the keys belong often does not exist anymore . In Palestinian posters and in signs carried in demonstrations, a key is used to denote the demand for the Palestinian Right of Return . </P>

The key fob you use to open your car before you get to it is an example of