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comment How broken is a xor of two LCGs?
@RamchandraApte, OK, you probably know more about x86-64 than I do. Would you like to do a back-of-the-envelope estimate of the performance of this stream cipher, on x86-64? How many cycles does a 64x64 multiple take?
Dec
10
awarded  Popular Question
Nov
30
comment Does MD5 hash have quasi commutative property?
What do you mean by quasi-commutative? Please expand your question with additional details, examples, etc. to clarify what you are asking. Also, tell us what you've tried and what research you've done.
Nov
30
comment Issue about randomness : what if random looks “human” ?
What do you mean by "what if"? (Yeah, well, it could happen. So what?) I honestly can't tell what your question is. Are you looking for a discussion, or do you have a specific technical question you are looking for an answer to? "What would we say?" is not a specific technical question.
Nov
30
comment transforming RC2 keys to have effective minimum length in implementations with fixed effective lengths
Why are you using RC2? Don't use RC2. It's not a good choice for any new design. Use a better cryptosystem, e.g., AES in an authenticated encryption mode.
Nov
13
awarded  Nice Answer
Nov
10
comment repeating-key xor and hamming distance
Hi @GabeHollombe, for new questions, I recommend you post a new question. But the short answer is: yes. If you guessed the key length correctly, you're looking at $\text{wt}(X \oplus K \oplus Y \oplus K) = \text{wt}(X \oplus Y)$, which is 2-3 bits. If you guessed it incorrectly, you're looking at $\text{wt}(X \oplus K \oplus Y \oplus K')$, which is about 3 bits (here all of $X,Y,K,K'$ are independently distributed English ASCII letters). ASCII lowercase letters are 0x61 to 0x7A, so the xor of four of those is close to uniform on its low 6 bits, and thus has 3 bits set on average.
Nov
9
comment Which attacks are possible against raw/textbook RSA?
What research have you done? There's lots written on this. See, e.g., Dan Boneh's survey. Or, search on "textbook RSA" on this site (or elsewhere) and you'll find many references.
Nov
3
comment Is splitting AES ecrypted data safe?
What research have you done? Have you looked at the other questions marked secret-sharing? Why are you considering this approach rather than one of the standard schemes that are mentioned in those other questions, such as Shamir secret sharing?
Oct
21
awarded  Notable Question
Oct
14
comment How costly is to find millions of large prime numbers for RSA?
@user153465, that's because pseudorandom generators require their seed to be uniformly distributed. The way to extract the entropy in a value and make it look uniformly distributed is to use a hash function. Justifying that would probably require some non-trivial cryptographic knowledge (e.g., the random oracle model, definitions of security of a PRG, and so on). Or, you can just trust me that this is a competently engineered cryptographic construction.
Oct
13
comment Weak key schedule IDEA
Nova, OK, I'm sympathetic. But the papers that describe the design of IDEA are cited in "Weak Keys for IDEA", which you link to in your post; see the introduction and references [1,2]. So, you can check for yourself whether the designers said anything on this topic in those papers. Are you familiar with how to do a literature search?
Oct
13
comment How to compute the decompositions used in fast FHE bootstrapping?
Are you really asking for an algorithm to represent an integer $x$ in base $b$? That's standard stuff. Have I misunderstood your question?
Oct
13
comment Weak key schedule IDEA
Nova, well, OK, what research have you done? Have you searched on Google Scholar? If that's what you want to know, you could edit your question to ask "Is there a paper explaining the design decisions that went into IDEA?". But, truthfully, that's not a good question -- the answer is yes there's such a paper and you can find your own using Google Scholar, so asking such a question would be a poor question because it would indicate you haven't done your research.
Oct
13
answered How costly is to find millions of large prime numbers for RSA?
Oct
13
comment Weak key schedule IDEA
How could anyone other than the designers of IDEA possibly answer this question with any degree of certainty? I suggest you edit the question to ask a technical question, one where answers can be supported by facts and reasoning and evidence, not a question that invites speculation (asks us to read the mind of the designers of IDEA).
Oct
13
comment Isn't 'exponent' only present in MSME equations in Groth-Sahai framework?
Don't use images as main content of your post. This makes your question impossible to search and inaccessible to the visually impaired. Please transcribe text and maths (note that you can use LaTeX) and don't forget to give proper attribution to your sources!
Oct
6
comment Does AES CTR mode store header information in encrypted files?
What research have you done? Counter mode is described in many places, including on Wikipedia, in a NIST standards document, and in textbooks. Have you checked those places to see what they say about this? I think you'll find a number of different ways of nonce management described there.
Oct
4
comment Witness and Commitment in Commitment schemes
This site is not a book recommendation service, but Lindell & Katz is good for much intro level material, and Goldreich's book is worth reading too.
Oct
4
comment Witness and Commitment in Commitment schemes
What research have you done? Have you read standard textbooks on commitment schemes? This is a very basic level question, and should be settled by reading standard references. I expect you to do a significant amount of research/self-study on your own before asking; this site is not a replacement for that.