4 ms·

It's time for a careful analysis by a qualified cryptographer of how key escrow weakens the protections encryption is supposed to afford. Schneier does conclud

It's time for a careful analysis by a qualified cryptographer of how key escrow weakens the protections encryption is supposed to afford. Schneier does conclude his post with a general "weakening encryption does more harm than good", but the title still uses the term backdoor. No one who's learned a bit about crypto (omitting Lindsey Graham here https://www.politico.com/news/2019/12/10/tech-companies-bipartisan-congress-encryption-080704 https://www.politico.com/news/2019/12/10/tech-companies-bipa...) is advocating for a "master key," short key lengths or backdoors that use obscurity to keep bad actors from exploiting them. Key escrow is real & already deployed in things like FileVault's Institutional Recovery Key https://support.apple.com/en-us/HT202385 https://support.apple.com/en-us/HT202385 All institutions don't use the same key and the vendor doesn't have to have a copy. [Microsoft offers companies a recovery mechanism too https://docs.microsoft.com/en-us/windows/security/information-protection/bitlocker/bitlocker-recovery-guide-plan https://docs.microsoft.com/en-us/windows/security/informatio...] My guess to how key escrow weakens protections is through implementation mistakes. Are there also mathematical weaknesses that effectively shorten the key length making brute force more feasible??? Why is the discourse on the anti-lawful-intercept side so imprecise?

driverdan 7y ago
Key escrow is still a backdoor.
TallGuyShort 7y ago
Key escrow doesn't change the fundamental mathematics behind the key. It's entirely an implementation detail / matter of trust. You're sharing what would otherwise be a secret with a new party. If they are untrustworthy or get compromised, it's no different than if you got compromised directly. But now you have roughly 2x the exposure.
SamuelAdams 7y ago
From the wikipedia page [1]: > The third party should be permitted access only under carefully controlled conditions, as for instance, a court order. Thus far, no system design has been shown to meet this requirement fully on a technical basis alone. All proposed systems also require correct functioning of some social linkage, as for instance the process of request for access, examination of request for 'legitimacy' (as by a court), and granting of access by technical personnel charged with access control. The social issue is a significant problem. How do you make sure court officials are not bribed? Who has access to the key escrow service, and what sort of checks make them trusted? Employees snoop on things all the time [2, 3, 4]: how are you going to ensure this does not happen with all communications for an individual? [1]: https://en.wikipedia.org/wiki/Key_escrow https://en.wikipedia.org/wiki/Key_escrow [2]: https://www.wired.com/2008/05/five-irs-employ/ https://www.wired.com/2008/05/five-irs-employ/ [3]: https://reason.com/2015/05/20/more-irs-employees-abuse-access-to-taxpa/ https://reason.com/2015/05/20/more-irs-employees-abuse-acces... [4]: https://www.accountingtoday.com/news/irs-celebrity-snoop-gets-three-years-probation https://www.accountingtoday.com/news/irs-celebrity-snoop-get...

driverdan 7y ago

Key escrow is still a backdoor.

TallGuyShort 7y ago

Key escrow doesn't change the fundamental mathematics behind the key. It's entirely an implementation detail / matter of trust. You're sharing what would otherwise be a secret with a new party. If they are untrustworthy or get compromised, it's no different than if you got compromised directly. But now you have roughly 2x the exposure.

SamuelAdams 7y ago

From the wikipedia page [1]: > The third party should be permitted access only under carefully controlled conditions, as for instance, a court order. Thus far, no system design has been shown to meet this requirement fully on a technical basis alone. All proposed systems also require correct functioning of some social linkage, as for instance the process of request for access, examination of request for 'legitimacy' (as by a court), and granting of access by technical personnel charged with access control. The social issue is a significant problem. How do you make sure court officials are not bribed? Who has access to the key escrow service, and what sort of checks make them trusted? Employees snoop on things all the time [2, 3, 4]: how are you going to ensure this does not happen with all communications for an individual? [1]: https://en.wikipedia.org/wiki/Key_escrow https://en.wikipedia.org/wiki/Key_escrow [2]: https://www.wired.com/2008/05/five-irs-employ/ https://www.wired.com/2008/05/five-irs-employ/ [3]: https://reason.com/2015/05/20/more-irs-employees-abuse-access-to-taxpa/ https://reason.com/2015/05/20/more-irs-employees-abuse-acces... [4]: https://www.accountingtoday.com/news/irs-celebrity-snoop-gets-three-years-probation https://www.accountingtoday.com/news/irs-celebrity-snoop-get...