Would be interested & interesting. Been doing the same thing with on-chipcard generated public keys to to the 'reverse' - be able to wipe a part of your off-site backup store by cutting up the secret. So I think there is a general case - and I've got a gut feeling that when propably analysed some of the usual assumptions around KDFs do not quite hold (as in effect one can often cause a lot of known plaintext to be passed in).
Dw. Op 3 sep. 2013, om 17:02 heeft Phillip Hallam-Baker <hal...@gmail.com> het volgende geschreven: > Want to collaborate on an Internet Draft? > > This is obviously useful but it can only be made useful if everyone does it > in the same way. > > > On Tue, Sep 3, 2013 at 10:14 AM, Peter Gutmann <pgut...@cs.auckland.ac.nz> > wrote: > Phillip Hallam-Baker <hal...@gmail.com> writes: > > >To backup the key we tell the device to print out the escrow data on paper. > >Let us imagine that there there is a single sheet of paper which is cut into > >six parts as follows: > > You read my mind :-). I suggested more or less this to a commercial provider > a month or so back when they were trying to solve the same problem. > Specifically it was "if you lose your key/password/whatever, you can't call > the helpdesk to get your data back, it's really gone", which was causing them > significant headaches because users just weren't expecting this sort of thing. > My suggestion was to generate a web page in printable format with the key > shares in standard software-serial-number form (XXXXX-XXXXX-XXXXX etc) and > tell people to keep one part at home and one at work, or something similar, > and to treat it like they'd treat their passport or insurance documentation. > > Peter. > > > > -- > Website: http://hallambaker.com/ > _______________________________________________ > The cryptography mailing list > cryptography@metzdowd.com > http://www.metzdowd.com/mailman/listinfo/cryptography
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