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visits member for 1 year, 11 months
seen Aug 24 at 16:23

Mar
11
asked How to best mix two arbitrary/random n-bit words?
Sep
22
awarded  Yearling
Jul
2
comment can permutation matrix be found in parallel processing technique?
I don't understand why "matrix" is essential for your question. That is, couldn't a bit string of size n be ok for the same context?
Mar
26
comment Any efficient text-based steganographic schemes?
A grille is commonly classified as a transposition cipher if I don't err.
Mar
23
comment Export from US of crypto software with key-size > 56 bits still needs permission?
Right. I simply want to caution too optimistic interpretations of that document without serious and careful examinations. (An analogy: certain commercial contracts commonly contain in footnotes and in difficult to read tiny fonts some "non-trivial" passages.)
Mar
23
comment Export from US of crypto software with key-size > 56 bits still needs permission?
Maybe I am thinking in a gravely wrong pedantic direction. But a software/technology which "has been" made available without restrictions ... is not identical to the same stuff that up to the present has not been made available ... but is now going to be made available ... for the first time, isn't it? If yes, that passage wouldn't as such exempt control and need of permission by some autorities of a first-time public introduction/disclosure of certain software/technology, if such authorities for whatever reasons "want" to do so by all means, I am afraid.
Mar
23
comment Export from US of crypto software with key-size > 56 bits still needs permission?
Is it really the case that open-source and free-of-charge alone will exempt from Wassenaar's requirements? I have the same doubts as rath. Could you be kind enough to cite the relevent passages or section numbers of the Wassenaar document?
Mar
20
comment Security of Deterministic Encryption Scheme
@sashank: The link I cited was intended for you to get some useful informations via comparing deterministic with probabilistic (non-deterministic) encryptions. You may also look at Wikipedia's article on deterministic encryption.
Mar
20
comment Security of Deterministic Encryption Scheme
See en.wikipedia.org/wiki/Probabilistic_encryption
Mar
20
revised Export from US of crypto software with key-size > 56 bits still needs permission?
added 5 characters in body
Mar
20
revised Export from US of crypto software with key-size > 56 bits still needs permission?
deleted 3 characters in body
Mar
20
answered Export from US of crypto software with key-size > 56 bits still needs permission?
Mar
18
comment Export from US of crypto software with key-size > 56 bits still needs permission?
But publishing on the Internet is export to the entire world, including the couple of blacklisted states, isn't it?
Mar
18
comment Export from US of crypto software with key-size > 56 bits still needs permission?
Do I understand you correctly that "strictly" speaking an approval would be needed but "defacto" the authority tolerates the online publications? (I just want to be 100% sure of having correctly understood the issue.)
Mar
17
asked Export from US of crypto software with key-size > 56 bits still needs permission?
Mar
3
comment How to solve the reverse of an equation that uses MOD?
@hsikcah: You have r=83172, b=3182, a=380951. b**(a-2)=62135 mod a. So v=r*62135=291905 mod a, and v*b=83172=r mod a, as required.
Mar
2
comment Are there any practical implementation of a homomorphic hashing or signature scheme?
@sashank: Note though that I had responded to your original (unedited) OP with a comment and given there a negative answer.
Feb
27
comment Are there any practical implementation of a homomorphic hashing or signature scheme?
As far as I know, there is yet no practically efficient implementation of fully homomorphic encryption on the horizon. So the answer to your question would evidently be negative, at least for a good hashing scheme, IMHO.
Feb
10
comment Can we replace the XOR operation in DES with some other operation?
If xor is used somewhere in encryption, that effect is reversed in decryption with xor. Similarly addition mod 2**n can be reversed with subtraction mod 2**n. So you could use instead of xor the modular addition. But the result isn't DES and I don't know what severe adverse effects one obtains with that kind of modification to DES.
Feb
10
asked Any historical accounts of cryptanalysis of Jefferson's wheel cipher?