Because they are valuable, commonly used, portable, and easy to hide in a backpack or other type of travel bag, laptops are often stolen. Every day, over 1,600 laptops go missing from U.S. airports. The cost of stolen business or personal data, and of the resulting problems (identity theft, credit card fraud, breach of privacy), can be many times the value of the stolen laptop itself. Consequently, physical protection of laptops and the safeguarding of data contained on them are both of great importance. Most laptops have a Kensington security slot, which can be used to tether them to a desk or other immovable object with a security cable and lock. In addition, modern operating systems and third-party software offer disk encryption functionality, which renders the data on the laptop's hard drive unreadable without a key or a passphrase. As of 2015, some laptops also have additional security elements added, including eye recognition software and fingerprint scanning components.