Apple Inc is resisting a federal court order that it help the US government break into the iPhone 5c of Rizwan Farook, who along with his wife killed 14 people in a December shooting in San Bernardino, California, which the government has described as a terror attack.

The government has asked Apple to create a new version of iOS that disables the auto-erase function. It also requested the new software circumvent a feature that causes delays of up to one hour when nine wrong passwords are entered – making it possible to break into the phone using the “brute force” method of trying millions of different passwords. The government says it is possible for Apple to create software that will only work on the device used by Farook.

Apple says that such a tool would essentially create a “backdoor” that could be used by the FBI or others to break into any iPhone. Apple CEO Tim Cook, in a letter to customers, cited the possibility of the specially created software falling into the “wrong hands” and rejected the notion that it would only be used in this single case.

Cook also said that the move would establish a dangerous precedent. “The government could extend this breach of privacy and demand that Apple build surveillance software to intercept your messages, access your health records or financial data, track your location, or even access your phone’s microphone or camera without your knowledge,” he said.

Even if the government is right in its assumption that the phone was used to plan that attack, Farook may have used encrypted apps that wipe all evidence of communications. For example, Islamic State uses an mobile messaging service known as Telegram for propaganda and recruitment. The service allows the group to broadcast messages to large numbers of followers, then move to private, one-to-one encrypted messaging that likely cannot be retrieved by forensics experts.

Smartphones powered by Google’s Android operating system offer a variety of encryption options, depending on the manufacturer and model. Forensic technicians can “bypass” passcodes on some of the devices, according to a November report by Manhattan’s district attorney. Google can remotely reset the passcodes, when served with a search warrant and an order instructing them to assist law enforcement to extract data, allowing authorities to view contents of a device.