This document is a tutorial on how to run the chat2 application in the spam-protected mode using the Waku-RLN-Relay protocol and with dynamic/on-chain group management.
In the on-chain/dynamic group management, the state of the group members i.e., their identity commitment keys is moderated via a membership smart contract deployed on the Goerli network which is one of the Ethereum testnets.
Members can be dynamically added to the group and the group size can grow up to 2^20 members.
To complete this tutorial, you will need 1) an account with at least `0.001` ethers on the Goerli testnet and 2) a hosted node on the Goerli testnet.
In case you are not familiar with either of these two steps, you may follow the following tutorial to fulfill the [prerequisites of running on-chain spam-protected chat2](./pre-requisites-of-running-on-chain-spam-protected-chat2.md).
Note that the required `0.001` ethers correspond to the registration fee,
however, you still need to have more funds in your account to cover the cost of the transaction gas fee.
At a high level, when a chat2 client is run with Waku-RLN-Relay mounted in on-chain mode, it creates an RLN credential (i.e., an identity key and an identity commitment key) and
If you choose not to reuse the same credential, then for each execution, a new registration will take place and more funds will get deducted from your Goerli account.
Under the hood, the chat2 client constantly listens to the membership contract and keeps itself updated with the latest state of the group.
In the following test setting, the chat2 clients are to be connected to the Waku test fleets as their first hop.
The test fleets will act as routers and are also set to run Waku-RLN-Relay over the same pubsub topic and content topic as chat2 clients i.e., the default pubsub topic of `/waku/2/default-waku/proto` and the content topic of `/toy-chat/2/luzhou/proto`.
Spam messages published on the said combination of topics will be caught by the test fleet nodes and will not be routed.
Note that spam protection does not rely on the presence of the test fleets.
In fact, all the chat2 clients are also capable of catching and dropping spam messages if they receive any.
1. Install Go language, by following the instructions from https://go.dev/doc/install and a C compiler (If using a debian based distro, you can run `apt install build-essential`)
2. Clone the repository
```
git clone https://github.com/status-im/go-waku
cd go-waku
```
## Build chat2
```
make chat2
```
## Set up a chat2 client
Run the following command to set up your chat2 client.
For the last three config options i.e., `rln-relay-eth-account-address`, `rln-relay-eth-account-private-key`, and `rln-relay-eth-client-address`, if you do not know how to obtain those, you may use the following tutorial on the [prerequisites of running on-chain spam-protected chat2](./pre-requisites-of-running-on-chain-spam-protected-chat2.md).
The registered RLN identity key, the RLN identity commitment key, and the index of the registered credential will be displayed as given below.
The RLN identity key is not shown in the figure (replaced by a string of `x`s) for security reasons. But, you will see your RLN identity key.
```
INFO: RLN config:
- Your membership index is: 63
- Your RLN identity key is: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
- Your RLN identity commitment key is: 6c6598126ba10d1b70100893b76d7f8d7343eeb8f5ecfd48371b421c5aa6f012
INFO: attempting DNS discovery with enrtree://ANTL4SLG2COUILKAPE7EF2BYNL2SHSHVCHLRD5J7ZJLN5R3PRJD2Y@prod.waku.nodes.status.im
INFO: Discovered and connecting to [/dns4/node-01.gc-us-central1-a.wakuv2.prod.statusim.net/tcp/8000/wss/p2p/16Uiu2HAmVkKntsECaYfefR1V2yCR79CegLATuTPE6B9TxgxBiiiA /dns4/node-01.ac-cn-hongkong- c.wakuv2.prod.statusim.net/tcp/8000/wss/p2p/16Uiu2HAm4v86W3bmT1BiH6oSPzcsSr24iDQpSN5Qa992BCjjwgrD /dns4/node-01.do-ams3.wakuv2.prod.statusim.net/tcp/8000/wss/p2p/16Uiu2HAmL5okWopX7NqZWBUKVqW8iUxCEmd5GMHLVPwCgzYzQv3e]
INFO: Connected to 16Uiu2HAmVkKntsECaYfefR1V2yCR79CegLATuTPE6B9TxgxBiiiA
INFO: Connected to 16Uiu2HAmL5okWopX7NqZWBUKVqW8iUxCEmd5GMHLVPwCgzYzQv3e
INFO: Connected to 16Uiu2HAm4v86W3bmT1BiH6oSPzcsSr24iDQpSN5Qa992BCjjwgrD
INFO: No store node configured. Choosing one at random...
```
You will also see some historical messages being fetched, again the content may be different on your end:
```
[Jul 26 10:41 Bob] hi
[Jul 26 10:41 Bob] hi
[Jun 29 16:21 Alice] spam1
[Jun 29 16:21 Alice] hiiii
[Jun 29 16:21 Alice] hello
[Jun 29 16:19 Bob] hi
[Jun 29 16:19 Bob] hi
[Jun 29 16:19 Alice] hi
[Jun 29 16:15 b] hi
[Jun 29 16:15 h] hi
...
```
Finally, the chat prompt `Send a message...` will appear which means your chat2 client is ready.
Once you type a chat line and hit enter, you will see a message that indicates the epoch at which the message is sent e.g.,
```
INFO: RLN Epoch: 165886530
[Jul 26 12:55 Anonymous] Hi
```
The numerical value `165886530` indicates the epoch of the message `Hi`.
You will see a different value than `165886530` on your screen.
If two messages sent by the same chat2 client happen to have the same RLN epoch value, then one of them will be detected as spam and won't be routed (by test fleets in this test setting).
You'll also see a `ERROR: validation failed` message
At the time of this tutorial, the epoch duration is set to `10` seconds.
You can inspect the current epoch value by checking the following [constant variable](https://github.com/status-im/go-zerokit-rln/blob/main/rln/types.go#L194) in the go-rln codebase.
Try to spam the network by violating the message rate limit i.e.,
sending more than one message per epoch.
Your messages will be routed via test fleets that are running in spam-protected mode over the same content topic i.e., `/toy-chat/2/luzhou/proto` as your chat client.
Your spam activity will be detected by them and your message will not reach the rest of the chat clients.
You can check this by running a second chat user and verifying that spam messages are not displayed as they are filtered by the test fleets.
A sample test scenario is illustrated in the [Sample test output section](#sample-test-output).
Once you are done with the test, make sure you close all the chat2 clients by typing the `/exit` command.
You may pass the `--rln-relay-cred-path` config option to specify a path for 1) persisting RLN credentials and 2) retrieving persisted RLN credentials.
RLN credential is persisted in the `rlnCredentials.txt` file under the specified path.
If this file does not already exist under the supplied path, then a new credential is generated and persisted in the `rlnCredentials.txt` file.
Otherwise, the chat client does not generate a new credential and will use, instead, the persisted RLN credential.
Note that the values used for `--rln-relay-eth-account-private-key`, and `--rln-relay-eth-client-address` in the following code snippets are junk and not valid.
The two chat clients namely `Alice` and `Bob` are connected to the test fleets.
`Alice` sends 4 messages i.e., `message1`, `message2`, `message3`, and `message4`.
However, only three of them reach `Bob`.
This is because the two messages `message2` and `message3` have identical RLN epoch values, so, one of them gets discarded by the test fleets as a spam message.
The test fleets do not relay `message3` further, hence `Bob` never receives it.
You can check this fact by looking at `Bob`'s console, where `message3` is missing.
- Your rln identity key is: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
- Your rln identity commitment key is: bd093cbf14fb933d53f596c33f98b3df83b7e9f7a1906cf4355fac712077cb28
INFO: attempting DNS discovery with enrtree://ANTL4SLG2COUILKAPE7EF2BYNL2SHSHVCHLRD5J7ZJLN5R3PRJD2Y@prod.waku.nodes.status.im
INFO: Discovered and connecting to [/dns4/node-01.gc-us-central1-a.wakuv2.prod.statusim.net/tcp/8000/wss/p2p/16Uiu2HAmVkKntsECaYfefR1V2yCR79CegLATuTPE6B9TxgxBiiiA /dns4/node-01.ac-cn-hongkong- c.wakuv2.prod.statusim.net/tcp/8000/wss/p2p/16Uiu2HAm4v86W3bmT1BiH6oSPzcsSr24iDQpSN5Qa992BCjjwgrD /dns4/node-01.do-ams3.wakuv2.prod.statusim.net/tcp/8000/wss/p2p/16Uiu2HAmL5okWopX7NqZWBUKVqW8iUxCEmd5GMHLVPwCgzYzQv3e]
INFO: Connected to 16Uiu2HAmVkKntsECaYfefR1V2yCR79CegLATuTPE6B9TxgxBiiiA
INFO: Connected to 16Uiu2HAmL5okWopX7NqZWBUKVqW8iUxCEmd5GMHLVPwCgzYzQv3e
INFO: Connected to 16Uiu2HAm4v86W3bmT1BiH6oSPzcsSr24iDQpSN5Qa992BCjjwgrD
INFO: No store node configured. Choosing one at random...
- Your rln identity key is: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
- Your rln identity commitment key is: bd093cbf14fb933d53f596c33f98b3df83b7e9f7a1906cf4355fac712077cb28
INFO: attempting DNS discovery with enrtree://ANTL4SLG2COUILKAPE7EF2BYNL2SHSHVCHLRD5J7ZJLN5R3PRJD2Y@prod.waku.nodes.status.im
INFO: Discovered and connecting to [/dns4/node-01.gc-us-central1-a.wakuv2.prod.statusim.net/tcp/8000/wss/p2p/16Uiu2HAmVkKntsECaYfefR1V2yCR79CegLATuTPE6B9TxgxBiiiA /dns4/node-01.ac-cn-hongkong- c.wakuv2.prod.statusim.net/tcp/8000/wss/p2p/16Uiu2HAm4v86W3bmT1BiH6oSPzcsSr24iDQpSN5Qa992BCjjwgrD /dns4/node-01.do-ams3.wakuv2.prod.statusim.net/tcp/8000/wss/p2p/16Uiu2HAmL5okWopX7NqZWBUKVqW8iUxCEmd5GMHLVPwCgzYzQv3e]
INFO: Connected to 16Uiu2HAmVkKntsECaYfefR1V2yCR79CegLATuTPE6B9TxgxBiiiA
INFO: Connected to 16Uiu2HAmL5okWopX7NqZWBUKVqW8iUxCEmd5GMHLVPwCgzYzQv3e
INFO: Connected to 16Uiu2HAm4v86W3bmT1BiH6oSPzcsSr24iDQpSN5Qa992BCjjwgrD
INFO: No store node configured. Choosing one at random...
