Coalitions representing Apple, Microsoft, Google, Amazon, and other tech companies have published an open letter expressing their concerns over a proposed US bill that would require smartphone makers to decrypt data on demand. In an open letter addressed to the bill's sponsors, Senators Richard Burr (R-NC) and Dianne Feinstein (D-CA), and signed by Reform Government Surveillance, the Computer and Communications Industry Association, the Internet Infrastructure Coalition, and the Entertainment Software Association, the coalition's members express their "deep concerns about well-intentioned but ultimately unworkable policies around encryption," as those would "weaken the very defenses we need to protect us from people who want to cause economic and physical harm. "

"We believe it is critical to the safety of the nation’s, and the world’s, information technology infrastructure for us all to avoid actions that will create government-mandated security vulnerabilities in our encryption systems."

Any mandatory decryption requirement, such as that included in the discussion draft of the bill would "force companies to prioritize government access over other considerations, including digital security."

A draft of the bill was published last week, in the wake of Apple's standoff with the FBI over access to an iPhone used by one of the shooters in the San Bernardino terrorist attack.

The bill's backers have sought to dispel concerns over privacy and security, arguing that it is critical to law enforcement. "No entity or individual is above the law," Feinstein said in a statement last week. "The bill we have drafted would simply provide that, if a court of law issues an order to render technical assistance or provide decrypted data, the company or individual would be required to do so."