layout
simple

A toy chain

The chain should have these properties:

• Running on at least 2 pre-defined nodes (IP addresses given in a config file / no additional discovery necessary)-
• PoW, with every node a miner-
• The difficulty is fixed (i.e., block time is not), each block rewards 100 coins-
• ECDSA cryptography; addresses may be pure public keys-
• Protect against double spending
• Transactions can have additional data payload, signed by the sender (and there needs to be a way to set it)
• Blocks can have additional data payload (and there needs to be a way to set it)
• Implement a simple REST-like web service API which implements the following services and returns JSON data:
  • Query the block count.
  • Query a single block and return all its transaction data.
  • Query a single transaction and return all its data.
  • Create a transaction from JSON data and accept it for mining.

Example of curl commands

# getting block count
curl http://127.0.0.1:8089/api/0.0/getheight
# getting 4th block
curl http://127.0.0.1:8089/api/0.0/getblock?n=4
# getting transaction Ztxrms5c5oKqb9Zof3xeC5Q2ZQjSaWv7FU4rAxe2s3sP
curl http://127.0.0.1:8089/api/0.0/gettx?txaddr=Ztxrms5c5oKqb9Zof3xeC5Q2ZQjSaWv7FU4rAxe2s3sP
# posting a transaction
cat txpool/tx.yml | sed -e "s/$/%0a/g" | curl -s -X POST http://127.0.0.1:8089/api/0.0/settx -d @-
# processing the txpool (mining)
curl http://127.0.0.1:8089/api/0.0/minepool

Security Warning

Blockchains are transparent and public so we encrypt private keys and other sensitive data, however as it is just a toy, we expose all the files for educational purpose.

** PLEASE DO NOT USE IN A PRODUCTION ENVIRONMENT **

note: sensitive data are encrypted w/ git-crypt; please send us your public key if you need access or ask for a shared DH secret

decrypt can be done with the command :

export GPG_ASKPASS=ssh-askpass
git-crypt unlock
#gpg --decrypt local.key.asc | git-crypt unlock -