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Working in industry as a cryptography engineer.

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


2d
comment vector space retrieval model
It's very unclear what you're asking. Can you give a little more detail?
Dec
8
comment Looking For Additively Homomorphic Encryption
Why can't you use hidden group order?
Dec
3
comment What cipher algorithm is this routine using?
This question appears to be off-topic because it is about a specific software implementation of cryptography.
Dec
3
comment Soundness of GRC.com Haystack padding concept
That website sets off several of my 'kook' alarm bells.
Dec
2
comment Using the same symmetric key in both directions?
This is verifiably false. Per-direction symmetric keys prevent replay attacks.
Dec
1
comment Verifying DER encoded DSA/ECDSA signature with extra content?
Well, what does the RFC say?
Nov
14
comment As a cryptographer, what are the things I should care about in my implementation of pairing functions?
In my opinion the question is too open-ended. You should ask specific questions about specific aspects of pairing implementations. Also pairings are a new and complex primitive that are still pretty niche. Also, you could ask the author of PBC this in an email.
Nov
10
comment What is the most computationally efficient way of generating pseudo-random permutations?
FFX and the oblivious card shuffles have identical use cases. They are both used in the same way to efficiently generate PRPs for arbitrary sets.
Nov
9
comment As a cryptographer, what are the things I should care about in my implementation of pairing functions?
On number 2, can you give a citation? I know there has been work that broke the DL problem for finite fields of small characteristic, but that work doesn't apply to ECDLP.
Nov
6
comment What is the most computationally efficient way of generating pseudo-random permutations?
In terms of the number of AES calls needed to encrypt a value, it would be more expensive. For your purposes the speed difference would probably not be significant, especially if you use AES-NI.
Oct
31
comment RSA Decryption given n, e, and phi(n)
Well, do you understand how RSA encryption and decryption work?
Oct
29
comment What are SNARKs?
eprint.iacr.org/2013/879 The citations from this should get you started.
Oct
23
comment Format Preserving Encryption for 32 or 64 bit plaintext values
I seriously doubt Voltage's patent covers as much as they say it does. Anyway, for small blocks you could use any of the FPE schemes based on oblivious card shuffles, e.g. the Thorp shuffle.
Oct
23
comment Format Preserving Encryption for 32 or 64 bit plaintext values
Also, to the OP: There are plenty of other schemes which achieve FPE that are not patented. Look (for example) at the BPS mode of operation, the spec of which is on the NIST modes development page.
Oct
23
comment Format Preserving Encryption for 32 or 64 bit plaintext values
Please, for the love of god do not make custom modifications to AES when there are other solutions that could work perfectly fine.
Oct
17
comment Prove that the affine cipher over Z26 has perfect secrecy if every key is used with equal probability of 1/312
Well, I'd start by reviewing the definition of perfect secrecy.
Oct
8
comment How costly is to find millions of large prime numbers for RSA?
OP: Are you implementing a Honey Encryption scheme for RSA secret keys?
Sep
30
comment Bridging the gap between security proofs and “real-world” security
Hmm... you might be right. I wouldn't be offended if people voted to close; this was just on my mind and I wanted to solicit input from the community.
Sep
30
comment Bridging the gap between security proofs and “real-world” security
I guess a salient example of this is encryption that preserves some functionality of the plaintext in the ciphertexts. Most good schemes in this area provide a proof of security based on a constructed model of the ideal functionality. How do we reason about the relevance of that model to a real deployed implementation of the scheme?
Sep
24
comment what is the difference between IBE and ABE schemes
This sounds like a homework question. Is it?