1,394 reputation
1720
bio website
location Bangalore, India
age 32
visits member for 2 years, 10 months
seen 7 hours ago

Security and Crypto Technologist


Feb
25
comment PRP, PRF and modular arithmetic
I believe , what could be found out from google , can be left for seekers exercise and save some time of one who answers it.
Feb
21
comment Which gives better deterministic encryption SIV or Plain ECB mode?
@pg1989 yes got it . so i dont have length preservation as criteria . the output could be longer .
Feb
19
comment Which gives better deterministic encryption SIV or Plain ECB mode?
Imagine some data type that is 128 bits like say IPv6 address and for some reason i want to encrypt it deterministically.
Feb
19
comment Which gives better deterministic encryption SIV or Plain ECB mode?
ok i meant message and block as same . let me edit the question
Feb
19
comment Which gives better deterministic encryption SIV or Plain ECB mode?
same holds good for ECB mode too .
Feb
13
comment Pseudo random permutation for arbitrary size domains
my last suggestion of , Feistel Networks + Cycle walking should help . please "PRP Luby Rack off revisited" by Naor and Reingold .
Feb
12
comment Pseudo random permutation for arbitrary size domains
@PaŭloEbermann using FPE with AES-NI is comparable speeds with AES-NI. Feistel networks with 10 or so rounds with AES-NI hardly slows it down .
Feb
12
comment Should tweak be unique per message?
well that is not the point , the TBC can be used in any mode, it is just a block cipher with additional input tweak , for all practical purposes its block cipher and can be used in any mode .
Feb
11
comment Should tweak be unique per message?
Tweaks are designed to provide randomness to block ciphers directly rather than using the block cipher in some mode. I cannot agree for few things in the answer. 1. "Tweaks are never used directly", check out the different modes of FPE, tweaks are given directly by the user. 2."None of these needs to be visible to a programmer...", same check FPE. Now with this its appropriate to ask the comparison if its more secure to use a block cipher + IV per message or use a block cipher + same tweak for all messages !
Feb
11
comment Should tweak be unique per message?
if the developer does not need to know about tweak , how is the tweak generated/provisioned/provided as input to encryption algorithm , how is the same tweak provided again to decryption algorithm run in a different machine ?
Feb
1
comment Is knowing the distribution of input domain only way to do cipher text only attacks?
either way would be of help .
Jan
31
comment Is it ok to send part of digital signature if we have bandwidth constraints?
how would you verify ? if you have only part of signature ?
Jan
30
comment Block cipher with key longer than block size
but the relation is not established correctly. the factor does not depend on cardinality of block size but cardinality on the set of permutations possible which is the crucial part to be specific
Jan
25
comment Impact of distinguishing between random text and cipher text?
stand corrected
Jan
24
comment Impact of distinguishing between random text and cipher text?
initially LR schemes suggested 4 , patarin proved its not enough and we need atleast 6 to get good security bounds
Jan
9
comment implication of tweak on bruteforcing a block cipher
i have added more details in my question .
Jan
9
comment implication of tweak on bruteforcing a block cipher
i have edited my question accordingly. so can you tell if tweak has an implication ?
Dec
14
comment What is the impact of different modes on pseudo randomness of AES?
@RichieFrame you mean if ecb used as PRF for more than one block u mean ? because below answer says so
Dec
12
comment What is the difference between PPE and SPPE?
yeah am aware of those references except Lee,Kim's one . am actually looking for Super PRP from PRF Constructions u mentioned of
Dec
12
comment What is the difference between PPE and SPPE?
@e-sushi can u give me pointer to luby-rackoff construction of SPRP you are talking about ?