Shadok

just a quick issue I found while editing: when two people edit an answer at the same time some strange things can happen: superuser.com/posts/541656/revisions

@JourneymanGeek I'll do sir! Better die tryin'

sorry i have to go get something to eat, brb. And thanks for your answers !

@JourneymanGeek votes should show you that theoritically

@JourneymanGeek ouch !

@JourneymanGeek I'm looking for my own rep per answer right now, i'm not very used to all the details in my profile

@JourneymanGeek Actually you raped that limit four times already ^^

@Sathya I'd like to but it's not that easy to do :) I never had a question to ask and answering can be challenging, given the quality of input from certain users I can only edit their posts to correct some mistakes/typo or add a few explanations

@Boris_yo Just use official sites, you'll get official sources/binaries and would likely contribute a little bit by displaying ads. Don't trust third-parties.

@Sathya thank you but eek! that's a very high level for such a thing as seeing why a post as been deleted.

@Boris_yo try FSLint if you use Linux

ok, i thought iw ould be able to at least see the reason for the delete, do you have an idea of how much point i need for that ?

hi! I received an upvote and a message (marked as a circled "1") on a deleted message, how come ? Here is the link to question: superuser.com/questions/235125/…

@ThomasPornin Sorry I have to go now. :/ That was very interesting , I may be here tomorrow, thanks again!

I see the parallel between a counter as an IV generator in CBC mode and my point above related to the similarity of outputs given input parameters but are we talking about the risk of having two GIF headers (copies) encoding the same way using the same IV if it's not unpredictable by the attacker ?

excellent ! I just bookmarked this conversation and I'm going to dig a little more on the BEAST attack which interests me (junior sys/netadmin here) and EAX could help me understand a use for MAC because I can't seem to grasp the interest (hash with a salt (=counter) per block maybe ?).

or maybe it's not a requirement as I thought.

@ThomasPornin ahem, "IV is meant to be publicly transmitted" as you stated seems to contradict my point, why require a crypto-safe PRNG in this case ? I'm always missing a little piece of info in your detailed answers ^^

I see the problem with ECB, same input + same key = same output , even with a salt you start with a handicap which could easily avoid given you have a "good" source of random to generate that first IV as used in CBC mode.

Oh right, that's the point of the prng on the first step in CBC, just because you need that first hash from a block you don't already have, nice !

@ThomasPornin I'll be back tomorrow but i may leave the window open for a few hours, I'll get back to you when I have time and maybe post my first links as a question, that could turn interesting. Thanks again for your kind explanations even though I can get a good hold on them, have a nice day and keep flowing those good answers on stackX !

Or could it be accepted as a question ? If so I'm posting it right now.

And while I'm thinking about it, isn't there already a place to store interesting things like the one I mentionned (that's a coompletely subjective point of view), maybe a page in a wiki ?

so instead of slowing the process you just "Enlarge you space" ? (yes I meant "search space" but I had to say it)

Great place here, come and blast your brain with crypto ^^ A bit hard but delightful anyway !

I tought there would be an equivalent in crypto

does that mean their only interest is in slowing the decryption process as salts do ? (even if there are IVs too in encryption which is used later)

... or we can reconstruct the s-box state from the key and find the coordinates of our encrypted input in the s-box to "decrypt" it ? That would make sense given the article cites the term of "confusion" as used by Shannon (which happened to interest me)

@ThomasPornin @Mvy Even if the description seems really clear to me here en.wikipedia.org/wiki/S-box I can't figure what is the output used for after that, i just lost a third of my information

@mvy oh ! ok in this case it makes sense but I jsut don't now yet the use of the output, I'm going to read that wkipedia page right now and get back when i'm done cause i need a few minutes

why does that seems like compression to me ? "6 bits input, 4 bits output", I'm must be missing soomething else

@ThomasPornin ok, i'm looking at the article :)

@Mvy are you telling me i'm wrong ? that would be pretty fun (and proving my point at the same time) !

I'll continue my search for 3DES modes specs for a few minutes, worst case i'll search through comments in libssl source code

ahah, i'm french, I already used that quote :)

I already searched and read a few papers on this but the schemas are really obscure for me ("S-boxes ? I heard there are some in blowfish which it's also used as a prng for scrypt" but that's where my comprehension stops due to my lack of skills in math/crypto :) ) Anyway it's always good to be told where to look precisely, I'll have a look at this article.

I think I'm understanding that (from a conceptual, not mathematical point of view)

I'm looking at that right now, that page is full of details :) openssl.org/docs/apps/enc.html (3des is supported in many modes cbc, ecb, ofb...)

@ThomasPornin For me IVs are the equivalent of salts in hashes, am I (approximately) right ?

I'm just thinking openssl should b able to decrypt it, I'll just try it now :)

@ThomasPornin great news so ! Thanks for that answer, I'll try to hack something in python but I'm not at ease at all

/me loves the "xxx" and "food" tags !

Context (part 2): That user, "A858DE45F56D9BC9" or the admin on reddit have deleted multiple times previous posts (for an unknown reason, at least to me) but knowing the community someone must have copies of those, if that message can be decrypted I will ask them happily :)

@Mvy I was just looking into that

For the context the reddit user named "A858DE45F56D9BC9" posts at (seemingly) random intervals message consisting of bunches of base64 strings, generally possesing some strange duplicate strings in a way which doesn't seem to indicate padding (maybe a few headers concatenated ?). See here for more: reddit.com/user/A858DE45F56D9BC9

fail on the paste... sorry !

oopsie