The mottled spread-spectrum bar code resembles the marbled cover of a composition notebook. It contains embedded correction parameters, and can encrypt and limit access to various levels of information. The bar code can be reset during inventory, and it can be used to track elapsed time, temperature or environmental conditions.
In fact, the code doesn’t actually have to be seen as a distinct bar code. It can be hidden in a logo, it can be designed to expire after a period of time, or it can indicate suspicion of tampering when used as a seal.