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| visits | member for | 1 year, 9 months |
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| stats | profile views | 137 |
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Nov 8 |
answered | Cryptanalysis of Linear Feedback Shift Registers |
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Nov 8 |
answered | Blowfish: hex digits of pi used for s-boxes? |
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Nov 5 |
comment |
RSA and prime difference @jug, If you want your key generation evaluated for NIST certification, and if they require that you add a check that $|p-q|$ be not too small, you do whatever they require you to do to comply with their standard. If your goal is compliance, there's no point asking us about what value of $\Delta$ to use; you just use whatever the standard (or the certifiers) tell you to use. In this case, though, compliance is orthogonal to the technical question of what is required for security. |
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Nov 5 |
comment |
RSA and prime difference OK, I provided the quantification you desired in my answer. (I still maintain that this question is not relevant to security in practice, given a proper implementation of RSA key generation, as it is dominated by other considerations.) |
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Nov 5 |
revised |
RSA and prime difference added 395 characters in body |
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Nov 5 |
revised |
RSA and prime difference added 395 characters in body |
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Nov 5 |
revised |
RSA and prime difference added 334 characters in body; added 268 characters in body |
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Nov 4 |
revised |
RSA and prime difference added 8 characters in body |
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Nov 4 |
revised |
RSA and prime difference added 8 characters in body |
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Nov 4 |
revised |
RSA and prime difference added 666 characters in body |
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Nov 4 |
comment |
CPA Secure Chosen plaintext scheme No. IND-CPA is a standard term for a particular definition of security (see any modern crypto-theory textbook for the precise definition). Roughly speaking, IND-CPA formalizes "indistinguishability under chosen-plaintext attacks", though of course you have to look at the precise mathematical definition to specify exactly what is meant by IND-CPA. (I'm not sure how we got here...) My point earlier was that when the original question mentions "IND-CPA", it was asking whether the scheme Enc_k meets IND-CPA; it's not something that implies that E_k is a block cipher/PRP. |
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Nov 4 |
comment |
CPA Secure Chosen plaintext scheme When you ask "is that a standard concept?", what are you referring to? IND-CPA is a standard concept. A PRF and PRP are a standard concept. The first encryption scheme presented here can be viewed as basically just counter mode. The second one is not standard, precisely because it is insecure. :-) Not sure if that answered your question. |
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Nov 4 |
comment |
CPA Secure Chosen plaintext scheme I think the "IND-CPA" in the question referred to the encryption scheme (Enc_k) not to the PRF (E_k). |
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Nov 4 |
answered | ECM Implementation is really slow |
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Nov 4 |
revised |
RSA and prime difference added 50 characters in body |
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Nov 4 |
comment |
RSA and prime difference @poncho, I'm not saying FIPS 186-3 said that -- I'm saying that SquareRootOfTwentyThree's question seemed to contain an implicit assumption that this is how we should pick RSA keys. |
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Nov 4 |
comment |
RSA and prime difference Your question seems to start from an assumption that there exists some $\Delta$ for which it is sensible/useful to check that $|p-q|\ge \Delta$. This assumption is not valid (in my opinion). Can you rephrase the question in a way that does not contain implicit assumptions? |
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Nov 4 |
comment |
RSA and prime difference There is absolutely no point in checking this condition (that $|p-q|\le \Delta$ holds). If you generated $p,q$ properly, the probability of a violation of this condition is about $1/2^{100}$, or negligibly small. Checking this condition is a waste of time and software development resources, adds unnecessary complexity, and just distracts people from the things that truly matter. It's far more likely that you have an error in the computation due to a cosmic-ray bitflip, than that $|p-q|$ happens to be too small when you generated $p,q$ by the proper procedure. |
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Nov 4 |
comment |
RSA and prime difference @SquareRootOfTwentyThree, sorry, I didn't know it covered RSA now. I edited my answer to reflect this. My bottom-line answer remains the same. |
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Nov 4 |
revised |
RSA and prime difference deleted 145 characters in body |
