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Signal adds a payments feature with a privacy-focused cryptocurrency

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Re: Signal adds a payments feature with a privacy-focused cryptocurrency

#71

Post by eMGm4D0zgUAVXc7 »

josh2600 wrote: post #4
leifg wrote: post #3

What's the consensus function you use on the mobile coin blockchain. Couldn't see if it's proof of work or proof of stake.

We use a modified version of the Stellar Consensus Protocol that we reimplemented from scratch using Rust. https://github.com/UkoeHB/Mechanics-of-MobileCoin/blob/maste... << Page 81 is where you want to go.

So this does seem to use some voting mechanism instead of scarcity through PoW.

How do you prevent the sybil attack then if there is no scarcity?

I.e. what prevents an individual from spinning up 10 million nodes to get more voting power?

Re: Signal adds a payments feature with a privacy-focused cryptocurrency

#72

Post by dunefox »

brodo wrote: post #24
qrbLPHiKpiux wrote: post #8

Is your backend open source, or not? Haven’t seen the git updated in a while.

Effectively not anymore. Here is a very recent german article about it: https://www.golem.de/news/crypto-messenger-signal-server-nic... No updates in the repo for over a year and no answers from the team. The whole crypto currency thing is also a red flag for me. Matrix seems to be the better option by now...

If anything, Threema is the best alternative.

Re: Signal adds a payments feature with a privacy-focused cryptocurrency

#74

Post by txr »

I'm not sure this solves any problem users have. Due to the nature of Signal requiring the phone number of the counter part to be in the phone book this feature will mostly be usable with friends or people you know directly. A feature which some users might want is to easily send money to a friend. These transfers will therefor be inherently be based on the countries currency. I'm not sure people will accept a cryptocurrency which value fluctuates in relation to the normal currency.

For other uses cases they can use a cryptocurrency directly (even MobileCoin) from another app. I can understand that cryptocurrencies are very interesting from a technical and cryptographic point of view. But in their current state most of them a more for speculation and doing state of the art computer science.

Therefore I think this totally useless in the signal app.

Re: Signal adds a payments feature with a privacy-focused cryptocurrency

#75

Post by crystaln »

hhjj wrote: post #60
edsimpson wrote: post #5

MobileCoin looks fantastic! Seems to solve the major pain points of Bitcoin: fast transactions, low transaction fees, private and no massive environmental impact with mining. Any ETA on when this will come to the USA?

Looks like it depends on SGX, so basically delegates trust to Intel. Bitcoin doesn't depend on trusting anyone.

SGX is only used for an extra layer of privacy, beyond what any other currency offers. SGX is not used for the security of the currency. This criticism has been answered countless times.

Re: Signal adds a payments feature with a privacy-focused cryptocurrency

#77

Post by josh2600 »

eMGm4D0zgUAVXc7 wrote: post #71
josh2600 wrote: post #4

Earlier quoted context omitted.

We use a modified version of the Stellar Consensus Protocol that we reimplemented from scratch using Rust. https://github.com/UkoeHB/Mechanics-of-MobileCoin/blob/maste... << Page 81 is where you want to go.

So this does seem to use some voting mechanism instead of scarcity through PoW. How do you prevent the sybil attack then if there is no scarcity? I.e. what prevents an individual from spinning up 10 million nodes to get more voting power?

Stellar is essentially a liquid democracy system similar to DNS. The core proof at the heart of David Mazieres paper is that in a densely interwoven graph, any set of nodes in a quorum slice reaching consensus is graph consensus. Regarding Sybil, nodes define their own trust relationships, so membership is open but not automatic.

Re: Signal adds a payments feature with a privacy-focused cryptocurrency

#78

Post by vitno »

fastball wrote: post #42
RL_Quine wrote: post #37

Earlier quoted context omitted.

> Signal Foundation is a 501c3 nonprofit. We’re proud of that designation and we’re out to prove that a nonprofit can innovate and scale as well as any business driven by a profit motive. https://signalfoundation.org/

Unsurprisingly money is still needed to pay for development and hosting costs, and Brian Acton's loan won't last forever.

This explicitly doesn't monetize Signal so this line of argument isn't particularly relevant.

Re: Signal adds a payments feature with a privacy-focused cryptocurrency

#79

Post by josh2600 »

fourstar wrote: post #70
josh2600 wrote: post #54

Earlier quoted context omitted.

Stellar actually does nothing to prevent double-spends as it is the consensus layer and not the ledger. The ledger prevents double spends in mobilecoin by using a proof called a "key image" which is part of CryptoNote ( https://bytecoin.org/old/whitepaper.pdf ). Essentially, a ring signature is produced by the user which says "one of these N transactions belong to me" and the key image proves that one of the members…

So essentially, this is a mashup between XMR (ring sigs) and XLM (consensus protocol)? Why not use zk-proofs?

If you can find a way to do ZK-proofs that work in the time constraints that we have (1-3 seconds end to end transaction completion and finality), then we'll switch to them. Right now this is the only way we could get the performance we wanted.

Re: Signal adds a payments feature with a privacy-focused cryptocurrency

#80

Post by ncmncm »

RL_Quine wrote: post #12

This is garbage, and shouldn't be part of Signal. Everything on the internet is being corrupted with adding cryptocurrency scams where they absolutely don't belong, it turns Signal from an obvious recommendation into something that makes me hesitate. There's something to be said for focusing on doing one thing well, and that doesn't mean turning a communication platform into a kitchen sink.

Agree. It would be OK to make Signal able to integrate payment systems and make this thing compatible with that or with any other comm that implements the interface. Tying them together is pernicious.

Anyway Signal is itself pernicious by being tied to a phone number and to Google Play services, and by being very choosy about who gets ports.

I had high hopes for Matrix, once they got E2EE, but they have flubbed that by requiring a very heavyweight bounce server that won't fit on (e.g.) your typical home router or super-cheap cloud VM. Matrix should enable a place to keep your message archive independent of the bounce server, and allow gatewaying a non-public storage service via the lightweight bounce service.

But Element.io's business model is tied to heavy-weight bounce service.

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