Do we have any rules about obvious homework questions and socratic responses? I could write a two-liner to answer crypto.stackexchange.com/q/58853/49826 but I feel the greatest value to anyone reading the question came out of the first comment I wrote, and to condense it into an answer that answers the question would detract from that value.

@SqueamishOssifrage Actually, there are no "rules" I'm aware of. But we do have somewhat of a guideline: crypto.meta.stackexchange.com/questions/626/…

Besides that, there's not that much related to homework/assignment Q&As

For a block cipher in CTR mode, wouldn't keeping the nonce secret theoretically improve security, since you'd need to know the nonce to generate the keystream?

@SqueamishOssifrage There is only one rule and it's time stamps

case in point, youtu.be/aB16fJpoj-I

IMO bobby fischer was an idiot expatriate

@Q-Club I do not get the case in point link and chessmaster reference. OTOH, there is no topicality rule for TSC, that's part of the fun.

@fgrieue exactly! Cryptography is as much about cultural slang as math

@forest this sounds like a somewhat interesting Q for the main site!

I thought about posting it there, but it seemed too much of a novice question. My hunch is that keeping the nonce secret would, at most, make known-plaintext attacks harder, which no modern widely-used block ciphers are vulnerable to.

@forest Keeping the nonce secret wouldn't necessarily hurt security, but the security of CTR mode doesn't rely on it. Conceivably, it might reduce the impact of multi-target attacks on, e.g., AES-128, turning them from maybe within the realm of feasibility for humanity to probably not within the realm of feasibility for humanity. But there's a much better way to do that: use AES-256.

hey is anyone on rn?

theres a little coding thing that

requires me to encode and decode base91

and then i take the decimal version of those into an array

and then i iterate over the array, giving me int/91 and int %91

is that not what it is?

@bleh as this is a place for Cryptography you may get lucky with your question here, but I wouldn't count on it and would suggest searching for a more appropriate room on Stack Overflow's chat?

just asking for how base 91 works

and apparently, my school deemed stack overflow chat inappropriate

:44364408    code_string = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
   x = convert_bytes_to_big_integer(hash_result)

   output_string = ""

   while(x > 0)
       {
           (x, remainder) = divide(x, 58)
           output_string.append(code_string[remainder])
       }

   repeat(number_of_leading_zero_bytes_in_hash)
       {
       output_string.append(code_string[0]);
       }

   output_string.reverse();

@bleh ^ this is for Base58

replace the code string with the one for Base91 and it should work

taken from: en.bitcoin.it/wiki/Base58Check_encoding

hmm

k

wait that literally is my algorithm :/

@bleh be happy then? :P

well it doesnt work D:<

whatever

thanks anyway

a wild vulture appears

notices how literally 5 people are in here and still nothing happens

it would appear everyone prefers silence

BTW @fgrieu, congratz on your 99% socratic badge!

@bleh Do you mean that you were advised that Stack Overflow chat is a toxic place, or that you were administratively or technically barred from reaching it?

@SqueamishOssifrage I would suppose the latter

maybe the just blocked "[*.]stackoverflow.com" to avoid students get cheap solutions? :p

@SEJPM I wanted to double-check straight from the horse's mouth before decrying the authoritarian thugs censoring the internet at an institution of higher education.

admin bar

stack overflow is fine, chat is not

@bleh Censorious authoritarian thugs! Shameful at an institution that bills itself as educational. Maybe you can use Tor to work around it.

lol if we download tor or shady stuff like that and the school finds out we die

@bleh Where are you, in Iran or something?

close, usa

lol

@bleh Whisky tango foxtrot!? If I may inquire, which institution of authoritarian reeducation is this? And what execrable administrative brownshirted tool forbid you from using Tor?

bellaire high school, blueshield or some fascist program

@bleh (No social obligation to answer: you are welcome to remain anonymous. But I hope the institution will not escape recourse for such bullshit.)

lol

@bleh Ah. I understand that in the United States, institutions of ‘education’ that precede ‘higher education’ are more blatant about their goals of indoctrination than universities are, and regularly employ various methods of incarceration, surveillance, and censorship to implement these goals.

For all the THINK OF THE CHILDREN rhetoric one hears from them, the yanks sure do seem to like imprisoning their children in the custody of fascist thugs.

Tor, shady stuff. Seriously!

Blocking a chat site = "imprisoning their children in the custody of fascist thugs."? :D

gimem a break

gimme*

@puzzlepalace I didn't say blocking a chat site is imprisoning their children in the custody of fascist thugs. I was referring to the systems of incarceration and surveillance, like detaining children after classes for failure to turn in homework or for walking to the bathroom without an authorization token, or hiring police to patrol school grounds and beat students up, or requiring metal detectors to enter the school, or installing spyware on students' laptops to watch them in their bedrooms, or…

Oh, I forgot one: dumping children's lunches on the floor in front of all their classmates for their parents' poverty. That's a great one. I could never have thought of that one myself.