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Working in industry as a cryptography engineer.

To contact me, email paulgrub AT umail DOT iu DOT edu


Sep
22
comment Checking the share membership in secret sharing schemes
I suspect this kind of distinguishing ability would break the information-theoretic security of the Shamir scheme, but I'm not sure.
Sep
19
comment reducing false positives in searchable encryption
David Wagner is a member of this community... Hopefully he'll see this and give you an authoritative answer :)
Sep
17
comment Secure order preserving hash function
To the OP: It's also possible to construct an order-preserving compression algorithm for strings: 1 2
Sep
17
reviewed Approve suggested edit on Pollard's Rho - Constructing the random function
Sep
3
comment Statistical tests for pseudorandom permutations
Also, my internal PRP in the FPE scheme is merely an unbalanced Feistel network similar to the Thorp shuffle.
Sep
3
comment Statistical tests for pseudorandom permutations
Yeah, I don't plan on relying solely on statistical tests to argue the security of my scheme. I think of passing statistical tests as a necessary but not sufficient condition for security.
Sep
3
comment Statistical tests for pseudorandom permutations
Saw that one. Thanks much :)
Sep
3
asked Statistical tests for pseudorandom permutations
Aug
29
comment How does Random Oracle and Standard Model differ?
Well, yes and no. The counterargument is that good crypto is about minimizing the assumptions you have to make. Assumptions are dangerous.
Aug
26
reviewed Approve suggested edit on How is SHA1 different from MD5?
Aug
13
comment How is SHA1 different from MD5?
I don't understand your question - every hash function can be described as having "chunks of bits, bit rotation, xor, and special functions".
Aug
10
comment Is HMAC-SHA-1 secure?
The gist is that the HMAC construction has properties which allow its security definition to be met even if the hash used internally is not a cryptographic hash. It need only meet a weaker definition, which is why HMAC-MD5 is also still considered secure.
Aug
8
comment Hardware Implementation of Pairing over BN curves
Whoa... that sounds really interesting. I only know epsilon about pairings, but do you have like a project page or a description of what you're trying to accomplish?
Aug
6
comment Homogenous and heterogeneous Unbalanced Feistel Networks
One person who could give a really good answer to this is Thomas Pornin... You could email him if you don't have a satisfactory answer in a few days.
Aug
6
comment How feasible is word-level frequency analysis over English (or any language)?
You can call it a codebook if you want, but it has nothing to do with ECB.
Aug
6
comment How feasible is word-level frequency analysis over English (or any language)?
Another thing that's been bugging me: Don't all these methods only work for guessing fairly common words from the corpus? If the word distribution is like most languages, there is a small subset of very common words at the top of an inverse-power-law curve, then most words are nearer to the bottom. For example, statistical attacks can easily guess which token corresponds to 'the' but 'finance' or 'contract' would be much harder to guess.
Aug
6
comment How feasible is word-level frequency analysis over English (or any language)?
Ahh I hadn't thought of using close-word statistics. Though doesn't that assume at least partially known plaintext?
Aug
6
comment How feasible is word-level frequency analysis over English (or any language)?
No it isn't. ECB is a block cipher mode of operation.
Aug
6
comment Straightforward method for hampering frequency analysis on deterministic encryption
Also - can the downvoter explain? I think this is a reasonably well-articulated question that is not too open-ended.
Aug
6
comment How feasible is word-level frequency analysis over English (or any language)?
Interesting, thanks for your answer. What if after tokenizing each document, the words in the document were shuffled according to some pseudorandom permutation like the Knuth shuffle? Something that is reversible with a secondary secret key that the adversary doesn't know.