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Security and Crypto Technologist


Oct
23
comment Format Preserving Encryption for 32 or 64 bit plaintext values
@Tim, To best of our knowledge there aren't any standards apart from NIST's FFX modes which are patented. Yes we did analyze FastPRP, these techniques work on very tiny spaces less than 16 bits , they tend to be expensive for 32 bits and above although we dont have bench marked results
Oct
9
comment Is .NET DESCryptoServiceProvider secure in this case?
Would suggest, you spend some more time on various modes. and find out which suits your application
Oct
8
comment Does this guarantee a unique 32 bit Hash?
@otus 20934 is the minimum i could get for MD5 , for SHA-256 it was more than 70k, just pull the code in any IDE eclipse or intellij and run it even on CLI .
Oct
8
comment Does this guarantee a unique 32 bit Hash?
@otus hardly few nano seconds may be . the program quickly exits. Even if i remove the "Hello" part. you can try it yourself its easy
Oct
8
comment Does this guarantee a unique 32 bit Hash?
@mikeazo not sure if you have noticed, it is not for entire MD5 but the tweaked version mentioned above, code is here pastebin.com/fZ1LR9as
Oct
7
comment Does this guarantee a unique 32 bit Hash?
i have written a bruteforce approach for MD5 in java for the above and i get collisions much sooner than 65536 limit which is 2^16. with SHA-256 am not getting the same
Oct
1
comment Why are we not using multiple ciphers per message?
@RickyDemer what does this mean ? "don't get ruled out"
Sep
25
comment What is Attribute Based Encryption?
@DrLecter , the paper , "Building Encrypted and Searchable log" has two schemes, the first one, i would say is symmetric ABE
Sep
23
comment reducing false positives in searchable encryption
what is his id ?
Sep
23
comment Is it possible to find out whether a number is greater than another number without knowing the numbers?
use orderpreserving encryption ?
Sep
22
comment Forward pseudorandom permutation
it is not clear what you want to achieve. what is the actual problem ?
Sep
22
comment Checking the share membership in secret sharing schemes
@GuutBoy, yes am considering the setting you described
Sep
22
comment Checking the share membership in secret sharing schemes
$P_i$ knows the secret and t,n parameters also.
Sep
22
comment Checking the share membership in secret sharing schemes
@pg1989 the distinguishing ability may break some security if other parameters like $t,n$ are not made available etc. here we are only speeding up the process of identifying the membership
Sep
22
comment Understanding Pseudo Random Generators
Check this video , good introduction with visualization usenix.org/conference/woot14/technical-sessions/presentation/…
Sep
20
comment What is Attribute Based Encryption?
@DrLecter can u point me to the "recursive secret sharing" schemes you were saying above ?
Sep
20
comment Does Ciphertext policy ABE support search operation on encrypted data
In theory , ABE, PBE are further generalized as Functional encryption. So is your question whether FE (or its variants) could be used for Searchable encryption ? if then how ?
Sep
19
comment Does Ciphertext policy ABE support search operation on encrypted data
It is not clear what you are asking. you may consider re-editing it. Are you asking if cp-abe supports searchable encryption by giving away appropriate keys ?
Sep
19
comment Authenticating Very Short (Sub-Block) Data
What if i dont want the tags for authentication and just the length preserving short block encryption is needed ? any suggestions apart from FPE techniques ?
Sep
13
comment breaking fully homomorphic encryption schemes
will the cipher text probabilistic in general ?