267 reputation
28
bio website
location Singapore
age 22
visits member for 1 year, 10 months
seen Apr 12 at 11:16

Apr
4
comment Is it possible to ensure security with zero pre-shared information?
@RickyDemer.. ok, but that's just being overly picky on his words...
Apr
4
revised Is timestamping possible without publishing?
added 16 characters in body
Apr
4
asked Is timestamping possible without publishing?
Apr
4
comment Why use a timestamp and how can someone know it's the correct one?
Do you have some examples? All the statements above seem vague...
Apr
4
suggested suggested edit on Random oracle model proofs and programmability
Feb
15
comment “SHA-256” vs “any 256 bits of SHA-512”, which is more secure?
@fgrieu, Thanks for the info =)
Feb
14
comment “SHA-256” vs “any 256 bits of SHA-512”, which is more secure?
Hmm, does SHA-512/512 share the same initialization value as SHA-512/256?
Feb
12
comment “SHA-256” vs “any 256 bits of SHA-512”, which is more secure?
@fgrieu, What's the difference between 512/224 and SHA-512/256? Are they just different names for the same thing?
Feb
12
accepted How can we sign a contract digitally between two parties?
Feb
12
revised How can we sign a contract digitally between two parties?
added 164 characters in body
Feb
11
asked How can we sign a contract digitally between two parties?
Feb
11
comment How does RSA signature verification work?
@poncho , you said that with a 2048 bit RSA key, we would be unable to directly sign any messages longer than 256 bytes long. Do you mean that there are no other solutions to sign a message longer than 256 bytes (e.g. 257 bytes) without first hashing it? In other words, do you mean that hashing is compulsory?
Jan
19
comment How to ensure that a “received value” is not altered?
@DrLecter, Yes it is based on human decision, but when my program record that decision, I want that record to be verifiable. So the user can lie and show us an altered record, but then we must be able to identify that it's fake. For example, he can say time=349058,amt=10,buy=100,sell=130,proof=GOI3098572GLIASD and we can tell whether it's real or fake. The trading site has APIs for me to do trades only, my program will record the trades done when they are done via my program.
Jan
19
comment How to ensure that a “received value” is not altered?
Yes, upon f(a) = b, the user submits c instead. I'm not sure what you meant when you say publishing the function can solve the problem. Publishing the function wouldn't help, since the function is Rand(0, 1) (for the actual function see the comment I wrote to DrLecter)
Jan
19
comment How to ensure that a “received value” is not altered?
@fgrieu, as my above comment to DrLecter, how could we modify the meaning of generating the message so that it becomes revealing an inherently verifiable message?
Jan
19
comment How to ensure that a “received value” is not altered?
@DrLecter, it's a program to help people trade more effectively by reducing much of the manual work involved. Basically, it works like an alternative GUI for a trading site. One of the features I'm trying to implement is to keep the "history" of trades. For example, we assume the user bought 30 stuff at £100‚Äč and sold them at £130 via my trading interface. Then, the interface would record this down in a history page. The user can share his history with anyone he wishes, but I'm trying to make it such that the results are verifiable (he cannot lie that he sold at £120 when he sold at £130)
Jan
19
comment How to ensure that a “received value” is not altered?
But the program is downloaded and run on the user's own computer, thus isn't there no way to hide the key from the user? As such, isn't using a MAC simply another form of obfuscation that can be easily defeated by a determined user?
Jan
18
revised How to ensure that a “received value” is not altered?
deleted 1 characters in body
Jan
18
awarded  Commentator
Jan
18
comment How to ensure that a “received value” is not altered?
@fgrieu, Since people can download and run the software, the key could definitely be extracted and leaked. Especially so since everyone's copy of the software is going to be using the same key for hashing/verifying right?