4 ms·

Show HN: P2P decentralized messaging application over Bitcoin Cash

zero_kool 8y ago
Video demo: https://youtu.be/9LqJeqwzwJs https://youtu.be/9LqJeqwzwJs
stephengillie 8y ago
The page shows little beyond a Play store link, a Youtube video, and some buzzwords that seem split between messaging and payment. > Start uncensorable chatting! You can soon start sending and receiving money from friends. From the video, the chats don't seem to be connected to any Coin - there's no mention of transaction fees to send or receive messages, and they seem to send and arrive nearly instantaneously - more like a Hangouts message than a Bitcoin payment. The app stores your private key too, so this chat service could be using standard public/private key encryption, and a chat server that uses public keys as usernames. Like a PGP chat server - that's in the same app as a Coin payment system, so you can have your private chats and your surreptitious payments in the same central location.
- sumanthneppalli 8y ago
  We should have explained better and we will improve our website, sorry about that. The blockchain that we are connected to is Bitcoin Cash(BCH). Bitcoin Cash is a fork of Bitcoin that aims at instant, cheap transactions. Bitcoin Cash transactions are instant unlike Bitcoin transactions. Each message costs around a cent as the fees is 1satoshi/byte(https://bitinfocharts.com/comparison/bitcoin%20cash-transactionfees.html https://bitinfocharts.com/comparison/bitcoin%20cash-transact...). The private key is being stored on the client side and we will open source the code soon so that users can verify that we do not store their private key. This is similar in functionality to Bitcoin wallets.
makomk 8y ago
This involves saving an encrypted copy of the message and unencrypted metadata about which identities are messaging each other when to the publicly-accessible Bitcoin Cash blockchain forever. Not only is this rather inefficient (every single full Bitcoin Cash node carries a copy of every user's messaging history forever), it's not good for privacy and definitely not "uncensorable". You're entirely reliant on miners including the messages in blocks and those full nodes giving you a copy of your messages on request.
- sumanthneppalli 8y ago
  The unencrypted metadata is a transaction between Bitcoin addresses, not mapped to any identity. This is similar to the Bitcoin network, where we just know that addresses contain a certain amount of Bitcoin but we cannot identify who the address belongs to. Compared to privacy apps such as Signal or Telegram, they have some metadata about users. One should think of a message as a small transaction that embeds some encrypted data on the blockchain. Miners are including messages on blocks because they get paid a small miner fee. These transactions are uncensorable because the Bitcoin network is uncensorable. Traffic of apps such as Telegram can be identified and blocked as Russia has done so in the past.
  - ShorsHammer 8y ago
    Bitcoins pseudonymous nature is getting weaker daily and blockchain analysis is maturing as a technology, the biggest coin mixer recently admitted that their services were useless and shutdown. There's very few exchanges if any in the western world where you can swap cash for bitcoin and not hand over ID. Blockchains are forever.
    - xiphias 8y ago
      Aftersignature aggregation between different inputs is implemented (probably in a few years), it will make mixing more efficient than normal (online) tranzactions. Hopefully it will give enough people incentive to use it.
- ShorsHammer 8y ago
  And absolutely terrifying the moment elliptical curves get broken.
  - sumanthneppalli 8y ago
    When elliptical curves get broken, Bitcoin is also broken. So we think this day is far off.
woah 8y ago
This is just putting messages directly on the blockchain
dotsh 8y ago
So many buzzwords but nothing interesting.
nickodell 8y ago
It looks like every message in this system create a new Bitcoin Cash transaction. Is that a good idea? You don't really need the consistency guarantees of the blockchain, so any gossip protocol would work equally well, and you wouldn't need to keep every message around forever. Also, this leaks unnecessary metadata. If you know Alice's address, and you know that she talked to Bob at 8:05 yesterday, you can figure out Bob's address by following the money.
- sumanthneppalli 8y ago
  There is no gossip protocol that is built over Bitcoin Cash right now. The only way to send data over the network is to create a transaction. If we want to use a gossip protocol, users will have to run federated servers and that requires a different incentive system. In this system, users pay a small fee and are assured that their message reaches the intended party. New addresses can be used for new chats, since these addresses can be generated randomly, there is no way to connect them to an identity. Money can be routed to the address through a Bitcoin mixer to increase anonymity. (https://news.bitcoin.com/coingeek-to-fund-the-bch-anonymizer-mixing-platform-cash-shuffle/ https://news.bitcoin.com/coingeek-to-fund-the-bch-anonymizer...)
  - nickodell 8y ago
    >Money can be routed to the address through a Bitcoin mixer to increase anonymity. [...] That's a cool solution to the problem, but you didn't need attach bitcoin addresses to it at all. For example, in Bitmessage, the source address is inside the encrypted portion. You can tell how many messages someone received, but not where they came from. If you separate your routing from your anti-spam incentives, your protocol will be more secure.
tehabe 8y ago
Does this mean I would need an own power plant to sent and receive message with this protocol?
- stephengillie 8y ago
  It would be like an IRC server where your username is your public key - and your messages are signed with the recipient's public key, so only the recipient can decrypt it. Like some kind of "PGP chat server". Unless you wanted Coin functionality included. Public rooms in the "PGP chat server" would have their public key as their room name. "Joining" the room would involve being sent the room's private key by an administrative bot. The server could send to all clients the full firehose of encrypted strings from all parties, and let the clients decrypt any messages they can. The clients could group chats into channels and messages by which private key successfully decrypted each string.
- sumanthneppalli 8y ago
  While the Bitcoin network does consume a lot of power, the Bitcoin Cash network is highly efficient and can process a lot of transactions with the same energy requirements. You would need to pay a fees of around a cent to send each message. You need not pay anything to receive a message. We believe that as the Bitcoin Cash network becomes stronger, transaction fees would get even cheaper.
  - aafdginionio 8y ago
    >the Bitcoin Cash network is highly efficient and can process a lot of transactions with the same energy requirements. Untrue. It's one order of magnitude better. That doesn't make it "highly efficient." Bitcoin is well over four orders of magnitude less efficient than Visa, which is appalling. Even a tenfold improvement over Bitcoin is still dog shit. And that's comparing to Visa, which isn't reasonable. Chat messages don't need the same guarantees as financial transactions. There's no need to put every chat message in a single ACID database. A system built specifically for chat (like Tox) can scale far better. >You would need to pay a fees of around a cent to send each message. Only because Bitcoin Cash isn't used for anything. If people start building applications that stress the network (like your chat application!), those fees will skyrocket. Fees are only low as long as the system has spare capacity. Low transaction fees are only evidence that the system is underused, which means no one's found a use case yet. >We believe that as the Bitcoin Cash network becomes stronger, transaction fees would get even cheaper. Blockchains are anti-scalable. As the network gets bigger and more popular, it gets no faster at all. It just gets vastly less efficient. More miners means more power consumption and more users means more congestion. There is no known way to scale these systems.
rawrmaan 8y ago
Just cause it CAN be done doesn’t mean it SHOULD be done.
- EGreg 8y ago
  WHY!
sschueller 8y ago
Why bitcoin cash and not bitcoin core or etherium?
- sumanthneppalli 8y ago
  Bitcoin and Ethereum are clogged and have hit their transaction capacity. Bitcoin cash is the only blockchain that has a scaling solution that works today and doesn't need any new innovation.
  - nipponese 8y ago
    Huge blocks are not a scaling solution, they are technical debt.
kemonocode 8y ago
This really looks like Bitcoin Cash propaganda, and really, not a very efficient way to do messaging at all. If you're interested in more practical approaches to do this instead of just shoving messages into a blockchain, Twister [1] does decentralized microblogging (a la Twitter) with e2e encryption for direct messages. Instead of using its "blockchain" to store every message, a Bitcoin-like protocol is used for authentication and a DHT network is used for the messages themselves. If the push came to shove, it'd be far easier to implement scaling or message pruning with this approach, while keeping the auth layer relatively limber. There's also Bitmessage [2] which uses a different approach and aims to hide metadata as well. Disclaimer: I've contributed to the Twister project. [1] http://twister.net.co/ http://twister.net.co/ [2] https://bitmessage.org/wiki/Main_Page https://bitmessage.org/wiki/Main_Page
- marknadal 8y ago
  Twister looks cool, I haven't seen it before. How long have you been helping with it? Using BitTorrent for these things seems like an obvious solution compared to everybody trying to do it on some blockchain (just not scalable). Although BitTorrent, in my experience, isn't the best at small rapid data, like tweets, versus large files/assets. Which is why I've worked on similar tech, for doing P2P stuff (short tutorial here: https://hackernoon.com/so-you-want-to-build-a-p2p-twitter-with-e2e-encryption-f90505b2ff8 https://hackernoon.com/so-you-want-to-build-a-p2p-twitter-wi... ), so I'd love to chat with you about how you did it for Twister and compare notes. Like, why couldn't you have done it all with BitTorrent, why did you need Bitcoin pieces? How did you get microblogging on BitTorrent to work efficiently?
  - kemonocode 8y ago
    My contributions to Twister are relatively minor- mostly focused towards UI/UX stuff, something I personally loathe, but figured it'd be good learning. Also, out of all projects that itch for a nail to smash with the Bitcoin hammer, it's one of the few that make the most sense to me. The reasoning to use a Bitcoin-based protocol for the auth layer is detailed in the whitepaper [1] but it's basically in order to have unique identities tied to a given username while still remaining decentralized. Just like with Bitcoin, there's Proof of Work needed to perform these validations, but instead of getting paid in coin, whoever finds a block has a chance to get a given message promoted for people to find more easily on their client. Does it scale? I'm not sure myself, it's working pretty well right now, but it certainly scales way better than using Bitcoin for every damn thing. In theory, you could use different protocols to those the original developer chose for all three layers since they're mostly independent (the user registration/auth layer, the DHT layer for messages themselves and the BitTorrent swarm layer for distribution and notification) [1] https://arxiv.org/abs/1312.7152 https://arxiv.org/abs/1312.7152
mtw 8y ago
I didn't get how the parties knows about new incoming messages. The app has a wallet that watches the blockchain for new transactions involving the user? What if the app is turned off? Or you guys have a central server that watches the blockchain and then updates users? In the case of a central server, does that mean this can be taken down if authorities take over the central server?
MertsA 8y ago
Ehhh... I like cryptocurrencies as much as the next guy but this feels like an attempt to shoehorn something into cryptocurrency "because blockchain". As far as I can see, ordering of messages is not protected at all without using the method that provides forward secrecy. Deniability is non-existent with this scheme. Every person you've ever sent a text to is saved accessible to everyone forever. It looks like messages aren't even padded at all other than just up to the 32 byte block. As far as the claim that it's somehow censorship proof, there's absolutely nothing at all here to prevent an adversary from identifying and blocking messages. It's a Bitcoin Cash transaction, but it's not magic. If Eve is in a position to block a message from Alice to Bob, Eve is also in a position to block a transaction from Alice to a miner. Also that Satoshi Nakamoto conversation is farcical to say the least. I honestly don't see a single advantage to this over existing solutions.

Video demo: https://youtu.be/9LqJeqwzwJs https://youtu.be/9LqJeqwzwJs

The page shows little beyond a Play store link, a Youtube video, and some buzzwords that seem split between messaging and payment. > Start uncensorable chatting! You can soon start sending and receiving money from friends. From the video, the chats don't seem to be connected to any Coin - there's no mention of transaction fees to send or receive messages, and they seem to send and arrive nearly instantaneously - more like a Hangouts message than a Bitcoin payment. The app stores your private key too, so this chat service could be using standard public/private key encryption, and a chat server that uses public keys as usernames. Like a PGP chat server - that's in the same app as a Coin payment system, so you can have your private chats and your surreptitious payments in the same central location.

sumanthneppalli 8y ago
We should have explained better and we will improve our website, sorry about that. The blockchain that we are connected to is Bitcoin Cash(BCH). Bitcoin Cash is a fork of Bitcoin that aims at instant, cheap transactions. Bitcoin Cash transactions are instant unlike Bitcoin transactions. Each message costs around a cent as the fees is 1satoshi/byte(https://bitinfocharts.com/comparison/bitcoin%20cash-transactionfees.html https://bitinfocharts.com/comparison/bitcoin%20cash-transact...). The private key is being stored on the client side and we will open source the code soon so that users can verify that we do not store their private key. This is similar in functionality to Bitcoin wallets.

makomk 8y ago

This involves saving an encrypted copy of the message and unencrypted metadata about which identities are messaging each other when to the publicly-accessible Bitcoin Cash blockchain forever. Not only is this rather inefficient (every single full Bitcoin Cash node carries a copy of every user's messaging history forever), it's not good for privacy and definitely not "uncensorable". You're entirely reliant on miners including the messages in blocks and those full nodes giving you a copy of your messages on request.

sumanthneppalli 8y ago
The unencrypted metadata is a transaction between Bitcoin addresses, not mapped to any identity. This is similar to the Bitcoin network, where we just know that addresses contain a certain amount of Bitcoin but we cannot identify who the address belongs to. Compared to privacy apps such as Signal or Telegram, they have some metadata about users. One should think of a message as a small transaction that embeds some encrypted data on the blockchain. Miners are including messages on blocks because they get paid a small miner fee. These transactions are uncensorable because the Bitcoin network is uncensorable. Traffic of apps such as Telegram can be identified and blocked as Russia has done so in the past.
- ShorsHammer 8y ago
  Bitcoins pseudonymous nature is getting weaker daily and blockchain analysis is maturing as a technology, the biggest coin mixer recently admitted that their services were useless and shutdown. There's very few exchanges if any in the western world where you can swap cash for bitcoin and not hand over ID. Blockchains are forever.
  - xiphias 8y ago
    Aftersignature aggregation between different inputs is implemented (probably in a few years), it will make mixing more efficient than normal (online) tranzactions. Hopefully it will give enough people incentive to use it.
ShorsHammer 8y ago
And absolutely terrifying the moment elliptical curves get broken.
- sumanthneppalli 8y ago
  When elliptical curves get broken, Bitcoin is also broken. So we think this day is far off.

woah 8y ago

This is just putting messages directly on the blockchain

dotsh 8y ago

So many buzzwords but nothing interesting.

nickodell 8y ago

It looks like every message in this system create a new Bitcoin Cash transaction. Is that a good idea? You don't really need the consistency guarantees of the blockchain, so any gossip protocol would work equally well, and you wouldn't need to keep every message around forever. Also, this leaks unnecessary metadata. If you know Alice's address, and you know that she talked to Bob at 8:05 yesterday, you can figure out Bob's address by following the money.

sumanthneppalli 8y ago
There is no gossip protocol that is built over Bitcoin Cash right now. The only way to send data over the network is to create a transaction. If we want to use a gossip protocol, users will have to run federated servers and that requires a different incentive system. In this system, users pay a small fee and are assured that their message reaches the intended party. New addresses can be used for new chats, since these addresses can be generated randomly, there is no way to connect them to an identity. Money can be routed to the address through a Bitcoin mixer to increase anonymity. (https://news.bitcoin.com/coingeek-to-fund-the-bch-anonymizer-mixing-platform-cash-shuffle/ https://news.bitcoin.com/coingeek-to-fund-the-bch-anonymizer...)
- nickodell 8y ago
  >Money can be routed to the address through a Bitcoin mixer to increase anonymity. [...] That's a cool solution to the problem, but you didn't need attach bitcoin addresses to it at all. For example, in Bitmessage, the source address is inside the encrypted portion. You can tell how many messages someone received, but not where they came from. If you separate your routing from your anti-spam incentives, your protocol will be more secure.

tehabe 8y ago

Does this mean I would need an own power plant to sent and receive message with this protocol?

stephengillie 8y ago
It would be like an IRC server where your username is your public key - and your messages are signed with the recipient's public key, so only the recipient can decrypt it. Like some kind of "PGP chat server". Unless you wanted Coin functionality included. Public rooms in the "PGP chat server" would have their public key as their room name. "Joining" the room would involve being sent the room's private key by an administrative bot. The server could send to all clients the full firehose of encrypted strings from all parties, and let the clients decrypt any messages they can. The clients could group chats into channels and messages by which private key successfully decrypted each string.
sumanthneppalli 8y ago
While the Bitcoin network does consume a lot of power, the Bitcoin Cash network is highly efficient and can process a lot of transactions with the same energy requirements. You would need to pay a fees of around a cent to send each message. You need not pay anything to receive a message. We believe that as the Bitcoin Cash network becomes stronger, transaction fees would get even cheaper.
- aafdginionio 8y ago
  >the Bitcoin Cash network is highly efficient and can process a lot of transactions with the same energy requirements. Untrue. It's one order of magnitude better. That doesn't make it "highly efficient." Bitcoin is well over four orders of magnitude less efficient than Visa, which is appalling. Even a tenfold improvement over Bitcoin is still dog shit. And that's comparing to Visa, which isn't reasonable. Chat messages don't need the same guarantees as financial transactions. There's no need to put every chat message in a single ACID database. A system built specifically for chat (like Tox) can scale far better. >You would need to pay a fees of around a cent to send each message. Only because Bitcoin Cash isn't used for anything. If people start building applications that stress the network (like your chat application!), those fees will skyrocket. Fees are only low as long as the system has spare capacity. Low transaction fees are only evidence that the system is underused, which means no one's found a use case yet. >We believe that as the Bitcoin Cash network becomes stronger, transaction fees would get even cheaper. Blockchains are anti-scalable. As the network gets bigger and more popular, it gets no faster at all. It just gets vastly less efficient. More miners means more power consumption and more users means more congestion. There is no known way to scale these systems.

rawrmaan 8y ago

Just cause it CAN be done doesn’t mean it SHOULD be done.

EGreg 8y ago
WHY!

sschueller 8y ago

Why bitcoin cash and not bitcoin core or etherium?

sumanthneppalli 8y ago
Bitcoin and Ethereum are clogged and have hit their transaction capacity. Bitcoin cash is the only blockchain that has a scaling solution that works today and doesn't need any new innovation.
- nipponese 8y ago
  Huge blocks are not a scaling solution, they are technical debt.

kemonocode 8y ago

This really looks like Bitcoin Cash propaganda, and really, not a very efficient way to do messaging at all. If you're interested in more practical approaches to do this instead of just shoving messages into a blockchain, Twister [1] does decentralized microblogging (a la Twitter) with e2e encryption for direct messages. Instead of using its "blockchain" to store every message, a Bitcoin-like protocol is used for authentication and a DHT network is used for the messages themselves. If the push came to shove, it'd be far easier to implement scaling or message pruning with this approach, while keeping the auth layer relatively limber. There's also Bitmessage [2] which uses a different approach and aims to hide metadata as well. Disclaimer: I've contributed to the Twister project. [1] http://twister.net.co/ http://twister.net.co/ [2] https://bitmessage.org/wiki/Main_Page https://bitmessage.org/wiki/Main_Page

marknadal 8y ago
Twister looks cool, I haven't seen it before. How long have you been helping with it? Using BitTorrent for these things seems like an obvious solution compared to everybody trying to do it on some blockchain (just not scalable). Although BitTorrent, in my experience, isn't the best at small rapid data, like tweets, versus large files/assets. Which is why I've worked on similar tech, for doing P2P stuff (short tutorial here: https://hackernoon.com/so-you-want-to-build-a-p2p-twitter-with-e2e-encryption-f90505b2ff8 https://hackernoon.com/so-you-want-to-build-a-p2p-twitter-wi... ), so I'd love to chat with you about how you did it for Twister and compare notes. Like, why couldn't you have done it all with BitTorrent, why did you need Bitcoin pieces? How did you get microblogging on BitTorrent to work efficiently?
- kemonocode 8y ago
  My contributions to Twister are relatively minor- mostly focused towards UI/UX stuff, something I personally loathe, but figured it'd be good learning. Also, out of all projects that itch for a nail to smash with the Bitcoin hammer, it's one of the few that make the most sense to me. The reasoning to use a Bitcoin-based protocol for the auth layer is detailed in the whitepaper [1] but it's basically in order to have unique identities tied to a given username while still remaining decentralized. Just like with Bitcoin, there's Proof of Work needed to perform these validations, but instead of getting paid in coin, whoever finds a block has a chance to get a given message promoted for people to find more easily on their client. Does it scale? I'm not sure myself, it's working pretty well right now, but it certainly scales way better than using Bitcoin for every damn thing. In theory, you could use different protocols to those the original developer chose for all three layers since they're mostly independent (the user registration/auth layer, the DHT layer for messages themselves and the BitTorrent swarm layer for distribution and notification) [1] https://arxiv.org/abs/1312.7152 https://arxiv.org/abs/1312.7152

mtw 8y ago

I didn't get how the parties knows about new incoming messages. The app has a wallet that watches the blockchain for new transactions involving the user? What if the app is turned off? Or you guys have a central server that watches the blockchain and then updates users? In the case of a central server, does that mean this can be taken down if authorities take over the central server?

MertsA 8y ago

Ehhh... I like cryptocurrencies as much as the next guy but this feels like an attempt to shoehorn something into cryptocurrency "because blockchain". As far as I can see, ordering of messages is not protected at all without using the method that provides forward secrecy. Deniability is non-existent with this scheme. Every person you've ever sent a text to is saved accessible to everyone forever. It looks like messages aren't even padded at all other than just up to the 32 byte block. As far as the claim that it's somehow censorship proof, there's absolutely nothing at all here to prevent an adversary from identifying and blocking messages. It's a Bitcoin Cash transaction, but it's not magic. If Eve is in a position to block a message from Alice to Bob, Eve is also in a position to block a transaction from Alice to a miner. Also that Satoshi Nakamoto conversation is farcical to say the least. I honestly don't see a single advantage to this over existing solutions.