Clojurians Log v2

@xcthulhu has joined the channel

@lvh Here

yay, this channel now exists for a reason

hi

It's nice to meet another person doing crypto with Clojure/ClojureScript

so much crypto

and macros named ✨

So it's been a massive effort to do ECC in ClojureScript

uhuh

do you care about running in browsers or something?

(also, how did you acquire that code? emscripten?)

Yeah, I want my app to be somewhat decentralized. Users should be able to sign their state and pass it to a third party for processing without necessarily going through my server.

But you still need to trust your server, right

Eh, not really.

You have to trust content delivery

I'd do content delivery via IPFS if I could, but maybe in 2019 or something

But I'd love it if someone else wanted to use the library I've been working on.

Sure; that’s what I meant by “trust my server” 🙂

or trust your server rather

anyway; so I do https://github.com/lvh/caesium

I’d like to make that work with libsodium.js in pure JavaScript at some point

but no guarantees when that happens

also potentially JS-but-ffi

for node

I wonder if you could reasonably test the property you care about (determinism) with test.check

It would seem that you could generate nilpotent sequences of operations

I dunno: see an array, copy it; see a map; split it in two and then merge the result

stuff like that

This is cool. Yeah, another reason to go with secp256k1 is that BitCoin already has a proper JNI interface to their library for that curve, which uses GMP to avoid timing attacks...

that might be easier than manual verification because your test stays

But it's not safe for other reasons.

makes sense

apropos: my “ECC for programmers” talk that I do (mostly internally) ends with breaking a secp256k1 impl that doesn’t check if points are on the curve correctly 🙂

I'm pretty crazy about enforcing that everywhere, actually

Anyway, so what do you do if you want to sign {:foo "bar", 123 {:baz 'symbol}}?

yeah; sorry; for clarity; that wasn’t a criticism of any software you wrote, just why I don’t like secp256k1

Ah, I don't like it because it's not a safe curve - https://safecurves.cr.yp.to/

that is one of the reasons it’s not a safe curve 🙂

(The attack I mentioned is on https://safecurves.cr.yp.to/twist.html)

ok

OK, so signing some data

first off; why do you care about canonicalization?

(I’m not saying that canonicalization is bad; just interested)

I want the client to be able to sign updates to their data when they make a delta, like {:old-hash [245 0 10 ...], :delta <...>, :new-hash [123 23 0 ...]}

Without them necessarily remembering the hashes; so they can remember what they incidentally sent, rather than what they must have sent?

Well, it's so a third party can reconstruct their transaction history

aha

in my case, txns are signed; so I can just go use the actual signature as a reference; I don’t necessarily care about it being reconstitutable from just the data

i.e. I validate txns before using them for anything anyway

(I dunno if it helps, but I’m using https://github.com/ptaoussanis/nippy)

I will file a ticket to see if peter has thought about this problem at all

test.check might already have something in its ecosystem to produce equal-but-different data structure

s

Yeah, it's worth digging in test.check...

I guess you probably care about hash-map vs array-map?

Not really, because I have to deal with stuff being in either Clojure or ClojureScript.

I don’t understand the implication

Oh, wait, maybe I do; just poor choice of words on my part

Well, does clojurescript even have array-maps?

You want (= a b) to imply (= (freeze a) (freeze b))

I’m trying to find a way to define that property cross-runtimely

I guess nippy is not relevant to you then because it’s Clojure-only 🙂

Yeah, I probably just need to do the silly canonical transformation thing. I probably could have something that doesn't load the stack up too high with clojure.walk

Does transit let you pick compressors?

Not in ClojureScript, no...

@donaldball has joined the channel

@lvh Since I'm hashing and flinging deltas around, compression isn't such a big deal...

@lvh One thing that sucks is that ClojureScript falls back on goog.math.Integers when deserializing java.math.BigIntegers, but they aren't actually usable because mulitiplication is broken for them - https://github.com/google/closure-library/pull/741

Gary is the man for trying to fix this mess