5 ms·

They could use multiple signing keys. One in America, one in Hong Kong, one in Germany, etc. If a firmware update is not signed in all (or N of M) jurisdictions

They could use multiple signing keys. One in America, one in Hong Kong, one in Germany, etc. If a firmware update is not signed in all (or N of M) jurisdictions, the secure enclave simply rejects it.

tlrobinson 11y ago
This is an excellent solution. A bit like Ripple's concept of trusting a set of validators are unlikely to collude against you, without having to trust any single one of them: https://wiki.ripple.com/Consensus#Not_colluding https://wiki.ripple.com/Consensus#Not_colluding Of course it doesn't stop any particular government from making it illegal to sell unbackdoorable phones in their country.
zik 11y ago
Or even better a single signing key for each phone so they don't get carte blanche access from a single request.
zekevermillion 11y ago
Here's another possibility. Let's say DOJ wins, or a new law is passed requiring Apple to sign malware version of iOS. Apple risks losing huge market share overseas, where people will stop buying iPhones. Apple spins off affiliate companies in these other countries, distributing controlling share of the affiliate stock to current Apple shareholders. Then apple just licenses its tech to the spin-off affiliates. No control over their ops. (Obviously would be more convoluted, much more -- but that's the basic idea.)
btbuilder 11y ago
This sounds like a good case for a threshold signature scheme[1] where no one member has all of a complete key and can partially sign without revealing their piece of the key to anyone. [1] http://www.iacr.org/archive/eurocrypt2000/1807/18070209-new.pdf http://www.iacr.org/archive/eurocrypt2000/1807/18070209-new....
- TillE 11y ago
  You don't actually need any new clever algorithms at all. At least on Windows, you can simply sign code with multiple certificates.
  - btbuilder 11y ago
    Aren't all algorithms "clever" at some level? I assume you are implying non-mainstream - that always carries risks, but there are some advantages: 1. The software that verifies the certificate doesn't need to be changed - which is quite an advantage if it has already been shipped, or if you need to change the signing rules at a later date. 2. The verification logic is exactly the same as if checking a regular, single signature certificate. Nice and simple, no bugs related to whether all criteria have been met by multiple certificates.

They could use multiple signing keys. One in America, one in Hong Kong, one in Germany, etc. If a firmware update is not signed in all (or N of M) jurisdictions, the secure enclave simply rejects it.

tlrobinson 11y ago

This is an excellent solution. A bit like Ripple's concept of trusting a set of validators are unlikely to collude against you, without having to trust any single one of them: https://wiki.ripple.com/Consensus#Not_colluding https://wiki.ripple.com/Consensus#Not_colluding Of course it doesn't stop any particular government from making it illegal to sell unbackdoorable phones in their country.

zik 11y ago

Or even better a single signing key for each phone so they don't get carte blanche access from a single request.

zekevermillion 11y ago

Here's another possibility. Let's say DOJ wins, or a new law is passed requiring Apple to sign malware version of iOS. Apple risks losing huge market share overseas, where people will stop buying iPhones. Apple spins off affiliate companies in these other countries, distributing controlling share of the affiliate stock to current Apple shareholders. Then apple just licenses its tech to the spin-off affiliates. No control over their ops. (Obviously would be more convoluted, much more -- but that's the basic idea.)

btbuilder 11y ago

This sounds like a good case for a threshold signature scheme[1] where no one member has all of a complete key and can partially sign without revealing their piece of the key to anyone. [1] http://www.iacr.org/archive/eurocrypt2000/1807/18070209-new.pdf http://www.iacr.org/archive/eurocrypt2000/1807/18070209-new....

TillE 11y ago
You don't actually need any new clever algorithms at all. At least on Windows, you can simply sign code with multiple certificates.
- btbuilder 11y ago
  Aren't all algorithms "clever" at some level? I assume you are implying non-mainstream - that always carries risks, but there are some advantages: 1. The software that verifies the certificate doesn't need to be changed - which is quite an advantage if it has already been shipped, or if you need to change the signing rules at a later date. 2. The verification logic is exactly the same as if checking a regular, single signature certificate. Nice and simple, no bugs related to whether all criteria have been met by multiple certificates.