257 reputation
16
bio website
location http://www.maths.manchester.ac.uk/~burdges/
age 38
visits member for 2 years, 11 months
seen Mar 4 at 13:40

Sep
12
awarded  Yearling
Jan
17
comment Information leakage from the ecryptfs filesystem
Is the only big difference between eCryptFS and EncFS that EncFS is userspace with all that entails, and requires users reserve another directory elsewhere for the encrypted files?
Dec
24
comment How does one design a traffic analysis resistant protocol?
Agreed, making the server useless was the whole point talking about "mailboxes". I think what I'd be most interested in is any rigorous analysis of what makes a server useless for traffic analysis while still making ordinary usage reasonable.
Dec
23
revised How does one design a traffic analysis resistant protocol?
added 173 characters in body
Dec
23
comment How does one design a traffic analysis resistant protocol?
I'd consider that "traffic analysis" refers to any attempt to discern the traffic pattern, but especially contacts/friends lists. I suppose one should view this on-server traffic analysis as a completely separate problem form internet traffic analysis.
Dec
23
awarded  Editor
Dec
23
revised How does one design a traffic analysis resistant protocol?
added 136 characters in body
Dec
23
comment How does one design a traffic analysis resistant protocol?
I'd implicitly assumed that the IM server cannot be trusted, maybe I should edit the question, but everything you say still applies of course. I suppose you could achieve this extra traffic merely by using Tor hidden services with all nodes configured as Tor relays.
Dec
23
asked How does one design a traffic analysis resistant protocol?
Dec
21
accepted How does the wider cryptographic community view non-abelian group based cryptography?
Dec
21
accepted Is there any serious discussion about using blinding intermediaries in digital currency scenarios?
Dec
21
awarded  Scholar
Dec
21
accepted How close is homomorphic encryption to handling regular expressions?
Dec
21
comment How close is homomorphic encryption to handling regular expressions?
Is homomorphic encryption even the correct term when we aren't talking about the ring structure? It'll work, I suppose.
Dec
21
asked How close is homomorphic encryption to handling regular expressions?
Dec
3
comment How do we find the last two correspondences in an otherwise known even permutation?
You could achieve sublinear space by modifying this algorithm to implement the set as a Bloom filters for the done array, but you must watch that the false positive rate doesn't grow too much, i.e. cycles cannot be too long. en.wikipedia.org/wiki/Bloom_filter
Dec
3
comment Could one prevent double spending in decentralized digital currencies (like Bitcoin) without all transactions being public?
Agreed, digital currency theory should remain inside crypto.SE.
Dec
2
awarded  Commentator
Dec
2
comment How do we find the last two correspondences in an otherwise known even permutation?
Yes, you must choose the queries, obviously. Just fyi, online algorithm is the technical term for an algorithm that acts on data arriving in a fixed sequence without any chance for going backwards.
Dec
2
comment How do we find the last two correspondences in an otherwise known even permutation?
Create an object Pmod with two variables a and b such that Pmod(a) = n-1, Pmod(b) = n-2, and Pmod(j) = P(j) otherwise. For i=0..n-3, if done[i]==0 then : Initialize j=i. Loop setting done[j]=1 and j=Pmod(j)$ until done[j]==1. If j==n-1, set a=i. If j==n-2, set b=i. You compute the answer using the final values of a and b.