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Security and Crypto Technologist


2d
comment Feistel network output if round function is the identity function
it is not clear from the question and identity function is just a wiki click away
Nov
25
comment Feistel network output if round function is the identity function
This question appears to be off-topic because it is about a home work problem and the questioner does not clearly say what he has tried so far. This might encourage more people to just post their question here and seek answers
Nov
25
comment Feistel network output if round function is the identity function
you should also tell us what you have tried so far. as such home work problems are not encouraged.
Nov
16
comment Secure symmetric encryption algorithm for any-size base62 data
are you looking for format preserving encryption ?
Nov
7
comment Can we give access to controlled functionality in Fully homomorphic encryption schemes?
the question was about controlled functionality for FHE but not FE
Nov
6
comment What is the most computationally efficient way of generating pseudo-random permutations?
If security is not a major concern , vanilla feistel network with AES-NI as PRF , with 6 rounds would be good enough thank FFX modes
Oct
30
comment Encrypting twice with same key gives back plain text
@owlstead looks like yes, thanks !
Oct
30
comment Encrypting twice with same key gives back plain text
the question is about block-cipher
Oct
30
comment Encrypting twice with same key gives back plain text
@squeamishossifrage the above question is about block ciphers , i thought it was explicit from the question i was pointing it , anyway edited it now to make it more clear
Oct
23
comment Recover plaintext from truncated ciphertext using AES for FPE
Why are you decrypting using AES ? AES_decrypt is never needed ! may be that is the reason you are not able to recover, share the code on pastebin.com or so , its easier that way for us to tell
Oct
23
comment Format Preserving Encryption for 32 or 64 bit plaintext values
Feistel networks with AES as PRF is the popular and well studied approach for Format Preserving
Oct
23
comment Format Preserving Encryption for 32 or 64 bit plaintext values
am curious which PRF should be used ? What would be the impact on security and performance. doing the above.
Oct
23
comment Format Preserving Encryption for 32 or 64 bit plaintext values
@pg1989 Voltage claims patents on BPS mode too , check this link voltage.com/technology/patents-research
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"