The motivation for this project is to explore creating a decentralized app (DApp) using the Ethereum Blockchain Platform. It's my first decentralized application!
The project uses the Whisper Protocol on Ethereum. It does not require Smart Contracts. Whisper uses a blockchain along with a distributed hash table (DHT) to provide secure, non-location based routing for communications. It supports unicast, multicast, and broadcast. Whisper's focus is security and is not meant to be performant-- although it is probably sufficient in most use-cases for light communication.
Two or more users would share a topic, a symmetrical key, and respective public keys with each other. All three are hashed together and sent into a DHT. The protocol listens to messages matching those hashes. When a match is found, the messages are routed to the parties listening.
The project is an unpacked create-react-app and uses the Web3.js library to communicate with a local geth process. geth is a golang Ethereum runtime.
I've included the geth binary in the repo for convenience. A popular library ganache does not yet have a Whisper implementation so geth seemed like my only option.
The project runs geth in rpc development mode with websockets enabled. Websockets are required for the Whisper's subscribe functionality. Otherwise, the protocol would be limited to unicast only.
All the chat-related code is in /src.
The project uses a static topic 0xffaadd11 as a common topic. However, the symmetrical key and the public keys are generated on mount. Users will need to join rooms via the symmetrical key -- called Room Hash in the application. Symmetrical keys, public keys, and topics are required to be in hexadecimal format when being sent into the protocol.
To display identities, I've "encapsulated" each message with a name required from each user. The client just splits it from the converted readable string coming back from Whisper.
There are several settings for the protocol. For the most part, I kept them at default because they were ideal for a chat project. TTL, for example, is at 10 seconds.
I plan to start another project to go in depth with topics, hashes, pow, and much longer ttl. Possibly a Twitter style app.
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Since
gethdoes not support SSL, you need something like nginx to be able to deploy this app over https or write your own server certificates which is beyond the scope of this project. -
There is an issue w/ Dockerizing the project due to a Web3 websocket dependency pointing to a repo without a commit hash. I'm still investigating the issue.
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Note that Infura, a popular dapp deployment platform uses ganache under the hood and thus, does not support Whisper.
Yarn seems to have issues with the Web3 library. Use npm.
npm install
npm start
- Write a wrapper for web3js.shh