Greenfield Challenger

Greenfield ensures data integrity by routinely issuing storage providers challenge events to prove that the stored data is not tampered with. This service allows end users to monitor the blockchain for challenge events and perform verification.

Disclaimer

The software and related documentation are under active development, all subject to potential future change without notification and not ready for production use. The code and security audit have not been fully completed and not ready for any bug bounty. We advise you to be careful and experiment on the network at your own risk. Stay safe out there.

Main Components

This off-chain application comprises 7 main goroutines: Monitor, Verifier, Vote Collector, Vote Broadcaster, Vote Collator, Tx Submitter and Attest Monitor.

1. The Monitor polls the blockchain for new blocks to parse for challenge events and adds them to the local db.

2. The Verifier is in charge of verifying the integrity of the stored data. The process involves querying the Storage Provider for the piece hashes and the Blockchain for the original hash. A root hash would be computed using the piece hashes received from the Storage Provider. Both the root hash and original hash would then be compared to check if they are equal before updating the db with the challenge results.

3. The Vote Broadcaster retrieves events that failed the verification process and were found to have mismatched hashes. A vote would be constructed and signed before being broadcasted to the blockchain where other Challenger services would be querying from to collect enough votes for a 2/3 consensus.

4. The Vote Collector polls the blockchain for votes that were broadcasted by other Challenger services and adds them to the local db. Votes will undergo validation before they are stored.

5. The Vote Collator retrieves events that failed the verification process to calculate an event hash. Every ChallengeId has a unique event hash and it would be used to identify votes that were saved in the local db by the Vote Collector. It will then query and collate the votes for a 2/3 consensus before changing the event status to allow the Tx Submitter to process it.

6. The Tx Submitter polls the db for events that received enough consensus votes and sends a MsgAttest to the blockchain after aggregating the votes and signature. The blockchain will validate the votes and if the attestation passes. the storage provider will then be slashed for failing to protect the integrity of the data that they were tasked to store.

7. The Attest Monitor polls the blockchain for the latest challenges that were successfully attested and updates the db with the attest results.

Deployment

Config

See config.json. Reference for a complete testnet config file.

1. Set your private key import method (via file or aws secret), deployment environment and gas limit.

     "greenfield_config": {
       "key_type": "local_private_key" or "aws_private_key" depending on whether you are storing the keys on aws or locally in this json file
       "aws_region": set this if you chose "aws_private_key"
       "aws_secret_name": set this if you chose "aws_private_key"
       "aws_bls_secret_name": set this if you chose "aws_private_key"
       "private_key": set this if you chose "local_private_key"
       "bls_private_key": set this if you chose "local_private_key" 
       "rpc_addrs": [
         "http://0.0.0.0:26750"
       ],
       "chain_id_string": chain id of the network, e.g., "greenfield_9000-121"
       "gas_limit": transaction gas limit, e.g., 1000,
       "fee_amount": transaction fees, e.g., "5000000000000",
       "fee_denom": transaction fees denom, e.g., "BNB",
       "no_simulate": simulate transaction, e.g., true
       "deduplication_interval": skip events that were recently processed, e.g., 100
     }
   

2. Set your log and backup preferences.

   "log_config": {
     "level": "DEBUG",
     "filename": "log.txt",
     "max_file_size_in_mb": 100 (file size threshold)  
     "max_backups_of_log_files": 2 (backup count threshold)
     "max_age_to_retain_log_files_in_days": 10 (backup age threshold)
     "use_console_logger": true,
     "use_file_logger": false,
     "compress": false
   }
   

3. Config your database settings.

   "db_config": {
     "dialect": "mysql",
     "db_path": "your_db_path"
     "key_type": "local_private_key" or "aws_private_key" depending on whether you are storing the keys on aws or locally in this json file
     "aws_region": set this if you chose "aws_private_key"
     "aws_secret_name": set this if you chose "aws_private_key"
     "username": set this if you chose "local_private_key"
     "password": set this if you chose "local_private_key"
     "max_idle_conns": 20, (set according to your db performance)
     "max_open_conns": 40, (set according to your db performance)
     "debug_mode": false  
   }
   

4. Set alert config to send a telegram message when the application exceeds the max retries for certain operations.

   "alert_config": {
     "identity": your_bot_identity
     "telegram_bot_id": your_bot_id
     "telegram_chat_id": your_chat_id  
   }
   

Run Locally

Run MySQL in Docker

docker run --name gnfd-mysql -p 3306:3306 -e MYSQL_ROOT_PASSWORD=root -d mysql:5.7

Create Schema

Create schema in MySQL client:

CREATE SCHEMA IF NOT EXISTS `challenger` DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci;

Run Greenfield locally in Greenfield repo

# please refer to greenfield repo for more information
make build
bash ./deployment/localup/localup.sh all 1 7 

Get validator bls key and challenger key

You can use the following approach if you do not know how.

$ ./build/bin/gnfd keys export ${BLS_KEY_NAME} --unsafe --unarmored-hex --home=${CLIENT_KEYRING_DIR} --keyring-backend=test
$ WARNING: The private key will be exported as an unarmored hexadecimal string. USE AT YOUR OWN RISK. Continue? [y/N]: y

$ ./build/bin/gnfd keys export ${CHALLENGER_NAME} --unsafe --unarmored-hex --home=${CLIENT_KEYRING_DIR} --keyring-backend=test
$ WARNING: The private key will be exported as an unarmored hexadecimal string. USE AT YOUR OWN RISK. Continue? [y/N]: y

Update config.json for keys, and MySQL

Start challenger

make build
./build/greenfield-challenger --config-type local --config-path ./config/config.json

Contribute

Thank you for considering to help out with the source code! We welcome contributions from anyone, and are grateful for even the smallest of fixes!

Please fork, fix, commit and send a pull request for the maintainers to review and merge into the main code base if you would like to.

Please make sure your contributions adhere to our coding guidelines:

• Code must adhere to the official Go formatting guidelines (i.e. uses gofmt).
• Code must be documented adhering to the official Go commentary guidelines.
• Pull requests need to be based on and opened against the master branch.
• Commit messages should be prefixed with the package(s) they modify.

License

The repo is licensed under the GNU Affero General Public License v3.0, also included in our repository in the COPYING file.