11 reputation
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bio website staff.science.uva.nl/~ciancia/…
location Amsterdam, Netherlands
age
visits member for 2 years, 1 month
seen Dec 21 '13 at 10:31

I am a travelling salesman, I spoke to God, I know the truth, but that's not because He told me.


Sep
24
awarded  Autobiographer
Oct
19
comment Self-expiring symmetric keys, or: cryptography in absence of secure deletion
My stronger constraint is that we do not trust the server, so we can not count on secure deletion. However, I am interested in solutions that involve some trust in a third party (that could become a peer to peer algorithm maybe)
Sep
30
comment Self-expiring symmetric keys, or: cryptography in absence of secure deletion
Well, I think it's "very standard" to encrypt something with a (randomly chosen) symmetric key and then encrypt the key with a private key. But yes, one needs to "bring around" Priv to access the data. Think there is one H for each piece of data C, so it would be unpractical to bring it with you when storing many data, while Priv is just one piece of information.
Sep
28
comment Self-expiring symmetric keys, or: cryptography in absence of secure deletion
@David Wachtfogel: I need that, since users should be able to get all of their data from the server, without storing anything else (think dropbox, or wuala, for the matter).
Aug
27
comment Self-expiring symmetric keys, or: cryptography in absence of secure deletion
Yes I imagine the random stream is available only for some time. Thinking about it, I can think of methods to "slow down" the stream in various ways, so for the moment let's assume the random stream generates a "large enough" number just "when I need it". Then I can encrypt the current key with the current number, and store the result on the server. Then I just need to refresh the key "when I need it".
Aug
24
awarded  Student
Aug
24
asked Self-expiring symmetric keys, or: cryptography in absence of secure deletion