unencrypted FTA viewers. Periodically, a provider will change the processes in which its encryption information is sent. When this happens, illegitimate viewing is disrupted. Third-party coders may release an updated altered version of the FTA receiver software on internet forums, sometimes hours to days after the countermeasure is implemented, although some countermeasures have allowed the encryption to remain secure for several months or longer. The receivers, meanwhile, remain able to receive unencrypted DVB-S broadcasts and (for some HDTV models) terrestrial ATSC programming. The same is not true of standard subscription TV receivers, whereby unsubscribing from a pay-TV package causes loss of all channels. The use of renewable security allows providers to send new smart cards to all subscribers as existing compromised encryption schemes (such as Nagravision 1 and 2) are replaced with new schemes (currently Nagravision 3). This "card swap" process can provide pay-TV operators with more effective control over pirate decryption, but at the expense of replacing smart cards in all existing subscribed receivers. While this approach is used by most providers, deployments tend to be slowed due to cost. While smart-card piracy often involves individuals who re-program access cards for others (usually for a price), piracy using FTA receivers involves third-party software that is relatively easy to upload to the receiver and can even be uploaded using a USB device, network, or serial link (a process called "flashing"). Most such firmware is distributed freely on the Internet. Websites that third-party coders use to share this software often have anywhere from 50,000 to over 200,000 registered users. Another method of pirate decryption that has become popular recently is known as Internet Key Sharing (IKS). This is accomplished by an Ethernet cable hooked to the receiver that allows updated decryption keys to be fed to the unit directly from the internet. The DVB-S common scrambling system and the various conditional access systems are based on the use of a legitimately subscribed smart cards which generates a continuous stream of cryptographic keys usable to decrypt one channel on a receiver. A key-sharing scheme operates by redistributing these keys in real-time to multiple receivers in an unlimited number of locations so that one valid smartcard may serve almost 10000 viewers. this was the only active pirate decryption system still in widespread use in North American satellite TV, due to the shutdown of the compromised Nagravision 2 system by providers such as Dish