Apple's CEO Tim Cook has reacted sharply to a federal court order in the U.S. that would require the company to help the FBI search the contents of an iPhone 5c seized from Syed Rizwan Farook, one of the terrorists in the San Bernardino, California, attack on Dec. 2.The U.S. government "has demanded that Apple take an unprecedented step which threatens the security of our customers," Cook wrote in an open letter to customers posted on Apple's website on Wednesday. He added that the moment called for a public discussion and he wanted customers and people around the country "to understand what is at stake."The tech industry has been increasingly using encryption in its products and services. The move has been criticized by U.S. government officials, including FBI Director James Comey, who say that it makes it more difficult for them to track terrorists who take cover under the encryption. The industry has taken the stand that encryption protects individual privacy and it opposes any mandatory backdoors.After the government told the court they were stymied by an auto-erasure feature in the iPhone that could erase data after 10 unsuccessful tries to crack the iPhone passcode, U.S. Magistrate Judge Sheri Pym of the U.S. District Court for the Central District of California on Tuesday ordered Apple to offer its technical assistance, including if required by providing signed software, to bypass or disable the auto-erase function whether or not it has been turned on in the device. That would enable FBI investigators to try different combinations to break the passcode and get to the data."Apple's reasonable technical assistance may include, but is not limited to: providing the FBI with a signed iPhone Software file, recovery bundle, or other Software Image File ( "SIF") that can be loaded onto the SUBJECT DEVICE. The SIF will load and run from Random Access Memory ( "RAM") and will not modify the iOS on the actual phone, the user data partition or system partition on the device's flash memory," Judge Pym added in her order. "The SIF will be coded by Apple with a unique identifier of the phone so that the SIF would only load and execute on the SUBJECT DEVICE."The government is asking Apple to build a backdoor to the iPhone, said Cook who added that what the government was asking it to provide was something that the company did not have and also considered too dangerous to create."Specifically, the FBI wants us to make a new version of the iPhone operating system, circumventing several important security features, and install it on an iPhone recovered during the investigation," Cook said. "In the wrong hands, this software \u2014 which does not exist today \u2014 would have the potential to unlock any iPhone in someone\u2019s physical possession."Apple has five business days to appeal against the order on grounds that it would be unreasonably burdensome for it to follow the ruling. The government has argued that the phone used by Farook runs iOS 9 and the company has the ability to assist the government despite its claims that it has written the software differently in the newer versions of the software, it added.Although it has helped the government in some cases, the company has recently fought against helping the government to unlock phones, when asked to under instructions under the All Writs Act. A similar case is pending in a New York federal court where the government wants to access the passcode-protected phone of a defendant in a criminal suit.