D.W.

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May 16	comment	SHA-1:Is there any mathematical result that gives us the minimum number of 1's in a 160-bit SHA-1 hash output? @Adnan, see pg1989's answer for the correct approach to get the right answer.
May 16	comment	What is a fair exchange scheme? Have you done a literature search on fair exchange protocols? If you've found only one paper, you've done it wrong.
May 16	comment	True random numbers generated by sensors @user1028028, why you need something that's a TRNG? What's wrong with a cryptographic-quality PRNG? Most people who think they need a TRNG, don't actually need one, and would actually be better off with a crypto-strength PRNG. (And are you aware that if you're hashing or otherwise processing sensor output, you've essentially built a crypto-strength PRNG, not a TRNG?)
May 16	comment	SHA-1:Is there any mathematical result that gives us the minimum number of 1's in a 160-bit SHA-1 hash output? Adnan, your calculation of the probability in the second half of the question is wrong.
May 16	comment	Generating IV in TLS 1.2 How do you know that it's safe to re-use the same key for encrypting the IV and for CBC encryption? That smells fishy to me. (For instance, in a chosen-nonce chosen-message attack scenario, this smells like it might allow distinguishing attacks.) Superficially, re-using the same key in this way seems like dangerous practice, unless there's a proof of security to demonstrate that nothing can go wrong. Do you know of a proof of security for this construction?
May 15	comment	Is there a way to do fair exchange between two parties who don't trust each other? "there has been done very little research in this area" - Not true. There have been tons of papers written on fair exchange protocols. (Google Scholar turns up over 100.) Have you done a literature search? You should.
May 14	comment	CSPRNG in JavaScript using Audio and Video "Which mode should I use for AES encryption?" - None of them. Encryption is the wrong primitive here. You want to use a cryptographic PRNG (which may involve hashing low-entropy data, so it might use a hash function); but you really don't want to build one of those yourself, you're better off using a carefully-vetted scheme and implementation built by someone who knows this stuff cold.
May 14	comment	CSPRNG in JavaScript using Audio and Video "Gathering binary data from a webcam/microphone" - This is not a good solution for a web application (written in Javascript, and running in the browser). First, only modern browsers support access to the webcam/microphone from Javascript (without using Flash), but if the user has a modern browser, it'll probably support window.crypto.getRandomValues() too, and in that case you're better off using the latter. Second, even if the browser allows access to webcam/microphone, it'll prompt the user to grant access. Users may be reluctant to grant your website that access; then whatcha gonna do?
May 13	comment	Is there a way to do fair exchange between two parties who don't trust each other? I think you know this, but just to be very explicit: The protocol in this answer doesn't meet the requirement of the original question. If Alice is malicious, she can arrange to learn Bob's message without revealing her own message.
May 13	comment	Why is the following RSA PRNG cryptographically secure? It's not cryptographically secure. Why do you think it is? Where did that premise come from? You might want to investigate where you got that assumption from -- that might help you answer your question yourself.
May 12	comment	Combining LFSRs for Stream Ciphers: Why do we need high non-linearity? @DilipSarwate, absolutely, great point! My answer keeps it simple and assumes the feedback polynomial / tap locations are known. Yes, if the feedback polynomial is not known, then twice as many bits of known keystream are needed, and more sophisticated methods are needed. Thank you for pointing this out!
May 10	comment	How to do a literature search I'm hoping this may generate a good reference question that will be generally applicable, so when people have questions about how to find research papers on topic X, we can refer them to this question for a good starting point.
May 10	comment	random number generator 10-side dice alternative I don't understand. What problem are you trying to solve, that dice don't solve? Do you just want something different for the sake of being different? Or do you have some specific metric that you're trying to optimize, where you want something that's better than dice on that metric? If the latter, can you be more explicit about what that metric is?
May 10	comment	Cryptography based upon neural networks Jager, do you know how to do a literature search? If not, I suggest that you ask a question about how to do a literature search/review; that will be broadly useful to others. Alternatively, if you do know how to do a literature search, your first step should be to conduct a literature review first, to find all the research you can that seems related to this subject, and then read the papers you've found. That should help you figure out whether you have a more concrete, answerable question about this subject.
May 10	comment	Trying to better understand the failure of the Index Calculus for ECDLP What's the question again? I see some reasonable statements, but I'm having a hard time understanding what is the question you want an answer to. Can you try to formulate a concrete, answerable question?
May 10	comment	Cryptography based upon neural networks This site is not a good place for general, open-ended discussions ("I would like you to express your opinions about [broad subject]"). Instead, it is for concrete questions with a correct answer. Please read the FAQ before asking questions.
May 10	comment	Security of Salsa20 with some known plaintext? It depends. There are many details. For instance, if you use a key derived from a password, it'll likely be insecure. If you fail to use authenticated encryption (e.g., a MAC), it'll be susceptible to chosen-ciphertext attacks. There are a number of ways to go wrong. Usually you shouldn't try to encrypt in this way; instead, you should use an existing, well-vetted scheme/software, like GnuPG
May 9	comment	What kind of adversary is the cloud? It might be silly for Amazon to attack their customers, but that doesn't mean the semi-honest threat model is a good one for treating Amazon's cloud services. See my answer for explanations/details on why.
May 8	comment	Increased CRC collision probability when adding bits to input message I don't understand what this has to do with cryptography. A CRC is not cryptographically secure.
May 8	comment	Injecting salt into PyCrypto KDF - useful? Regarding your edit: Understood. That last link does talk about concatenation, but it is talking in the context of an ordinary hash function (which does not intrinsically support a salt). That's different from PBKDF2. PBKDF2 is designed to support salts, so the answer for PBKDF2 is different than for a vanilla cryptographic hash. Oleksi's answer remains the correct one.