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Mar
14
comment How to best mix two arbitrary/random n-bit words?
The specific application that interests me currently would certainly be deemed too mundane from a theoretical point of view. In a certain encryption processing I am considering there are two n-bit words, x and y, one on the plaintext side and one on the ciphertext side (but neither is directly plaintext or ciphertext). I like to combine them into z and sum the z's of all preceding blocks into a value s and use that to chain the blocks. It's my thinking that, if z is "somehow" optimal in capturing the randomness of x any y, then the chaining would also be fine. Would that satisfy your query?
Mar
14
comment How to best mix two arbitrary/random n-bit words?
What I would prefer to have is not to use, if possible, a rather complex computation like a crypto-secure hash function but some more simple computations in practice, of the genre of xor you mentioned. For it is not extremely high crypto security that is demanded in the cases I have in mind but, roughly speaking, certain comparatively good security that could be obtained with some not too expensive computing expenses.
Mar
12
comment How to best mix two arbitrary/random n-bit words?
I am merely using an example to answer your question of defining "optimally". That is, the notion of "better" exists in the present context. My problem as such is evidently indepent of what one could best do with that specific potential application.
Mar
11
comment How to best mix two arbitrary/random n-bit words?
Let's consider the following case: Suppose one encrypts 2 natural language texts (there are estimates of some 1 bit pro character, if I don't err) with a certain block cipher to obtain 2 sequences of blocks. Now one desires to combine these sequences into one sequence with the goal that the resulting sequnce is hopefully better in the sense of entropy. (If I don't err, measuring entropy is difficult, but it seems nonetheless not incorrect to expect/demand that the resulting sequence should have higher entropy.)
Mar
11
comment How to best mix two arbitrary/random n-bit words?
ok. Let's say one has in some crypto processing obtained x and y and then need to combine them into z for going further, how should one do that optimally?
Mar
11
comment How to best mix two arbitrary/random n-bit words?
I am most interested in the case of pseudo-random, i.e. x and y are from some good crypto processing.
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?
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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.)