A host of technology industry groups and civil liberties advocates have filed legal arguments backing Apple in its fight with the FBI.
They include security experts worried about hacking and independent app-makers who fear more burdens on their business.
These “friends of the court” briefs aim to bolster Apple’s challenge of a court order that would force it to help FBI agents hack an encrypted iPhone used by a San Bernardino gunman.
The government must file its response next week, before a hearing on March 22.
Among those backing Apple are some of its biggest competitors, including Google, Microsoft and Facebook, which have signalled they will file a joint brief on Apple’s behalf.
A group of 17 smaller tech firms, including Twitter, LinkedIn, Airbnb and Reddit submitted a separate joint filing.
The phone at the centre of the dispute was used by Syed Farook, one of the gunmen who killed 14 people in San Bernardino.
Many, though not all, of the filings rehash arguments made by Apple itself in a court filing last week. For instance, a group of cryptographers and security experts warned in their brief that forcing Apple to write software that overrides iPhone security features would produce a dangerous new tool that itself would be vulnerable to theft or hacking.
An organisation of app makers, meanwhile, argued that the order would create untenable burdens for smaller tech companies and software developers who might be asked to create similar programmes for their own products.
“If the government prevails, then this case will be the first of many requiring companies to degrade the security and to undermine the trust in their products so essential to privacy in the digital age,” attorneys for the American Civil Liberties Union warned in their brief, adding that the precedent would implicate “the security and privacy of hundreds of millions of Americans”.
Security experts argued the government’s request is not as simple as it sounds. Any new software code is likely to have unexpected bugs that could be exploited by hackers, according to a brief from Stanford computer scientist Dan Boneh, cryptologist Bruce Schneier, independent researcher Jonathan Zdziarski and four others.
“The security bypass this court would order Apple to create almost certainly will be used on other iPhones in the future,” they warned. “This spread increases the risk that the forensic software will escape Apple’s control either through theft, embezzlement, or order of another court, including a foreign government.”
Meanwhile, the app-makers trade group, known as ACT, noted that Apple has said it would take “between six and ten” engineers to create the software. A similar demand “would be exceptionally onerous for the small companies that constitute the majority of ACT’s members and that are the heart of the mobile economy,” the group argued.
Telecommunications giant AT&T also filed a brief arguing that current law doesn’t support the government’s demand. AT&T urged the magistrate to rescind her order and let Congress address the issue.
Another trade group warned the order would undermine public confidence in “the integrity of the internet”. The Computer and Communications Industry Association said its members invest heavily in technical measures to protect customers’ information against theft by criminals and hackers backed for foreign states.
CCIA members include Google, Facebook, Amazon and Microsoft — but not Apple. The association has been at odds with Apple over various policy issues such as disputes over technology patents. But an official said the organisation believes Apple’s position is right for the industry and the country.