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Dec
6
comment How can I add more rounds to AES?
@quantumSoup, yes, but Bruce also wrote: "choosing the number of rounds for a cipher is a combination of experience and guesswork. The AES rounds of 10, 12, and 14 were arbitrary, but represented the designers' best guess as to what would be secure. In my 2000 paper, I recommended increasing the number of rounds considerably, based on my best guess at the time. The round recommendations I gave above -- 16, 20, 28 -- are designed to restore AES's security cushion. They're off the top of my head, and certainly not the last word on the topic."
Dec
6
answered Speeding up partially known plaintext preimage recovery attack on MD5
Dec
5
comment Webcam random number generator
@Thomas, Usually, the purpose of cryptography is to be secure against malicious attackers, not to "be creative". If you want to be secure, then you should use best practices, even if it feels like that's "repeating itself". A creative-but-insecure solution isn't going to help anyone.
Dec
5
answered How can I add more rounds to AES?
Dec
4
reviewed Approve suggested edit on Does RSA-OEAP have integrity and authenticity properties?
Dec
4
comment Sigma-protocol for 3SAT problem
Welcome to Crypto.SE! This looks like an interesting question, but it would help to have a little more information. What have you tried so far? What research have you done on your own so far? As the faq suggests, it is important to "do your homework" and show us what you've done so far. I encourage you to read the links in this comment -- they may provide helpful background about this site!
Dec
3
revised Bent Combining Functions
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Dec
3
comment Bent Combining Functions
@WilliamHird, OK, you are right! It does make sense to use standard terminology. I withdraw my comment about names. (A suggestion for future questions: maybe including the definition of the term you are asking about in the question would help others answer?)
Dec
3
comment Is Convergent Encryption really secure?
The probability of obtaining a weak key in this way is negligibly small (unless your crypto algorithm is incredibly broken). Better to worry about getting struck by lightning...twice...in the same hour.... or to worry that a cosmic ray may cause a bitflip error during the crypto computation and cause your secrets to be accidentally printed in the clear.
Dec
3
answered Bent Combining Functions
Dec
3
comment Webcam random number generator
I would want to see a lot more detailed analysis than that the idea "sounds good" before recommending this to users of cryptography. In other words: I don't think this is good advice to end users. I don't think it does a service to users to encourage them to roll their own entropy sources like this; I think giving users this kind of advice is likely to lead to increased incidence of poorly seeded crypo. Instead, I think it is better to stick to advising them to use standard, well-vetted crypto PRNGs provided by the system.
Dec
3
comment Webcam random number generator
@CodesInChaos, nonetheless, I stand by my comment. End users of cryptography shouldn't be rolling their own PRNG; they should use a standard system PRNG, and let the system designers take care of ensuring it has sufficient entropy. (Let the system designers choose to use webcam data if that is appropriate and improves security, but most users of cryptography should not be making decisions like this.)
Dec
1
revised Stopping timing attacks on AES: Why is it important to prevent the OS from interrupting the AES computation?
added 5 characters in body
Dec
1
comment Webcam random number generator
I've never heard of this randcam thing, and wouldn't recommend using it. Instead, I recommend using a standard random-number source, such as /dev/urandom, CryptGenRandom(), or similar (depending upon what platform your code is running on).
Nov
30
revised Stopping timing attacks on AES: Why is it important to prevent the OS from interrupting the AES computation?
added 1039 characters in body
Nov
30
revised Stopping timing attacks on AES: Why is it important to prevent the OS from interrupting the AES computation?
added 1611 characters in body; added 1522 characters in body
Nov
30
revised AES timing attacks
elaborate more on how attacker could get high-quality timing data
Nov
30
revised AES timing attacks
deleted 1 characters in body; edited tags
Nov
30
answered Stopping timing attacks on AES: Why is it important to prevent the OS from interrupting the AES computation?
Nov
30
revised Stopping timing attacks on AES: Why is it important to prevent the OS from interrupting the AES computation?
added 5 characters in body; edited tags; edited title