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Nov
7
revised Which attacks are possible against raw/textbook RSA?
added 76 characters in body
Nov
7
comment What is the value of Q such that Q|P-1 where P is a prime number?
I'm assuming $Q$ should be prime. If that is the exact wording of the problem, then it doesn't sound like it (though if that is the exact wording of the problem, then the problem is strange as $Q=1$ is an answer).
Nov
7
comment What is the value of Q such that Q|P-1 where P is a prime number?
BTW, there is a very simple answer that works for all primes but one.
Nov
7
comment What is the value of Q such that Q|P-1 where P is a prime number?
That notation means $Q$ divides $P-1$. In other words, divide $P-1$ by $Q$, is there a remainder, if so then $Q$ does not divide $P-1$, if not then $Q$ divides $P-1$.
Nov
7
answered Which attacks are possible against raw/textbook RSA?
Nov
7
comment Zero Knowledge Example using discrete log
BTW, please don't get discouraged by the down votes on the answer. I noticed in your profile that you are very interested in crypto. We are glad to have you here. Check out the Help Center to learn about the scope of this SE site.
Nov
7
comment Zero Knowledge Example using discrete log
@sayan, then you should state your assumption on computationally bounded adversary as "don't get any information" sounds like you are talking about information theoretic security (i.e., computationally unbounded)
Nov
7
comment What does “circuits” mean in Cryptography?
@GuutBoy no confusion. In boolean circuits addition and XOR are equivalent, multiplication and AND are the same thing. You can think of it as an arithmetic circuit over GF(2). You can get NOT using the XOR (addition) gate.
Nov
7
comment Repeated XOR decryption
Are you the same person that asked this? If so, you should merge your accounts.
Nov
7
comment Repeated XOR decryption
If that is all the information you have, likely you can't decrypt it. Do you have any additional information? For example, in the title you mention repeated xor. Do you know for a fact that the encryption method was repeated xor with some small key?
Nov
6
comment What does “circuits” mean in Cryptography?
@dorafmon Taken from here (yes it is 3d shaders, but it applies). Shader model 3.0, which is used in the latest PC hardware and on Xbox 360, has fully general looping abilities and is Turing complete in the theoretical sense. This rather nicely highlights the difference between theory and practice, though! When people claim a device is Turing complete, what they actually mean is "if this had infinite time and infinite storage, it would be Turing complete".
Nov
6
comment What does “circuits” mean in Cryptography?
@dorafmon, not turing complete due to the size issue pointed out in the link I posted. It is a different computation model. See the beginning of this chapter from Boaz Barak's book.
Nov
6
revised What does “circuits” mean in Cryptography?
added 494 characters in body
Nov
6
comment What does “circuits” mean in Cryptography?
@ThomasM.DuBuisson that (conditionals become bit masking where each branch is evaluated) is something that I think a lot of people miss. Thanks for pointing that out.
Nov
6
comment Is it possible to add OpenSSL engine for a block algorithm with different input and output block size?
I would think the openssl mailing list to be a much better place to ask this. Don't get me wrong. I am glad you are using our site and hope you continue to, but I just want you to get the best answer possible.
Nov
6
comment What does “circuits” mean in Cryptography?
@dorafmon, I found this answer and the comments to be interesting and related.
Nov
6
answered What does “circuits” mean in Cryptography?
Nov
5
reviewed Leave Open Isn't Groth-Sahai proof system applicable beyond Bilinear groups?
Nov
5
reviewed Close I need to know number of encryption/decryption operations?
Nov
5
reviewed Close The use of the term “sound” in cryptography