[Cryptography] Does this keying scheme make sense?

Jon Callas jon at callas.org
Sun Oct 22 00:37:10 EDT 2017

> On Oct 21, 2017, at 7:24 PM, John Levine <johnl at iecc.com> wrote:
> I was talking to a guy at a conference who sells a package which,
> among other things, encrypts files in cloud storage with each file
> having a different key.  The keys are all generated from a secret
> keystore seed in a way that is supposed to be secure.
> I'm looking at his patent on the technique and can't tell whether it's
> clever, or just overclever:
> https://patents.google.com/patent/US9703979B1/

I know this sounds bad, but it does not behoove anyone who is an expert in the field to read someone else's patents. The reason is simple – knowing infringement is triple damages.

I can think of about ten ways to do this securely. If he invented an eleventh, I'd rather just award a golf clap from afar.


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