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13h
comment Is there any such thing as “proof of location”?
Can they be anywhere in the world? I.e., is there any bound on their distance from you? Not sure if this is really the right site for this question. Security.SE may be better. We can migrate if needed.
20h
comment Has anyone heard of matrix-based “Roman Doll” encryption techniques?
where do those theorems come from? If you won't cite sources, it is going to be impossible for anyone to help you.
22h
comment Library to find an addition chain for a large number?
@Chris, now that you've implemented it, are you going to open source it? If you do, add a link in the question. While the question was put on hold, since it has an upvote, it won't be deleted. Could be useful to someone in the future.
23h
comment Permuting Small Sized Set in Practice
@user13676 There are a lot of posts on this kind of stuff online. Most programming languages have methods to help with this.
1d
comment Library to find an addition chain for a large number?
@Chris, I suggest another edit. Questions asking for tools are generally not well received on this site. Also, you still haven't explained the relationship to cryptography.
1d
comment Permuting Small Sized Set in Practice
@user13676 The state of the random number generator. If you need it to be "keyed" so you can reproduce the permutation, then seed the random number generator.
1d
comment Library to find an addition chain for a large number?
what do you mean by "addition chain"? Also, what is the relationship to cryptography?
2d
comment Simulator in Private Outsourced Computation over Outsourced Datasets
@user13676 you should ask that as a separate question, instead of in the comments.
Jul
24
comment Terminology: differences between the terms “pre-master secret”, “master secret”, “private key”, and “shared secret”?
$R_{bob}$ would be a new random number every time, AFAIK. So it wouldn't be anything in the cert. Though things can change quite a bit for specific cipher suites. If there is a specific cipher suite you are interested in, I'd ask that as a separate question. My answer most relates to the RSA cipher suite.
Jul
24
comment Can a 1 byte difference in AES 128 bit keys make huge difference in output?
RE: security, if that is your question, you should edit that in. As is, your question just asks if making a 1 byte change in the key results in a huge change in the ciphertext. Does AES have stronger avalanche effect compared to what?
Jul
24
comment Can a 1 byte difference in AES 128 bit keys make huge difference in output?
You can test this yourself echo abcd | openssl enc -aes-128-ecb -nosalt -K 000000000000000000000000000000ff -iv 00 | xxd -p, then change one byte of the key and try again.
Jul
24
comment Terminology: differences between the terms “pre-master secret”, “master secret”, “private key”, and “shared secret”?
+5 Sometimes I wish we could give extra rep points for really good questions. Who would have thought, someone actually searched around and read related questions before posting :)
Jul
23
comment What are the implications of a birthday attack on a HMAC?
I would think that this is only true for HMAC if a Merkle-Damgård hash function is used
Jul
23
comment How to find the crypt algorithm from a table of crypt vs results? I guess this is MD5
Are the inputs always 16 bytes? Or can you pass other strings?
Jul
23
comment Does pseudorandom secret sharing require a central dealer?
@user124384 Take a look at Martin Geisler's PhD dissertation it has a lot of detail. Especially about PRSS as implemented in VIFF. It has been a while since I have looked that closely at the PRSS stuff.
Jul
22
comment Decrypt ARC4 messages that are using the same keystream
See crypto.stackexchange.com/questions/59/… Reusing a key in a stream cipher has the same effect as reusing a one-time pad. Now, since it is RC4, there may be more advanced attacks. But with only 16-byte messages, I doubt it.
Jul
22
comment Question about the key in RC4
It looks like they are using AES in Counter mode, which basically turns AES into a stream cipher.
Jul
22
comment Question about the key in RC4
AES is a block cipher that can be operated in streaming modes. I have no experience doing voice encryption in this type of application, so I can't really recommend a mode. That is why I suggest looking at what others are doing. A stream cipher like Salsa20 may work just fine too.
Jul
22
comment Question about the key in RC4
@lena, "best" is hard for me to say given the amount of information I have. Given the fact that someone else is already using it for a similar application, I would say it has good potential. But, if you design your protocols such that they are not specific to one particular cipher, you can start with AES (not sure which mode OWS is using, but go with that too). Then you can switch things out if needed.
Jul
22
comment Question about the key in RC4
@lena, maybe not, but you can learn from what they are doing and try to apply some of the general ideas. For example, how are symmetric keys established? Etc. The fact that they are using AES w/o issue, says you probably can too.