# Protocol of the carrotcoin cryptocurrency

The carrotcoin cryptocurrency is a bitcoin-like currency with proof-of-work, created just for learning purposes.

# Blockchain

The network should stabilize at around 1 block every 5 minutes.

Blocks are hashed with SHA256 and need to start with a certain number of zeros (or, more precise, be below a given value depending on the difficulty)

ed25519 keys are used to validate transactions.


## block datastructure

| content | size (bytes) |
|---|---|
| previous hash | 32 |
| message (arbitrary) | 32 |
| nonce | 8 |
| timestamp (unix time in seconds, BE) | 8 |
| block id (BE) | 4 |
| miner pubkey | 32 |
| transaction (optional) | 148 |

If no transaction is included, its 148 bytes are all null.

The first block has block id 0 and a "previous hash" value of 32 null bytes.

## transaction datastructure

1 carrotcoin (cc) consists of 100 cents

| content | size (bytes) |
|---|---|
| id (arbitrary) | 4 |
| sender (pubkey) | 32 |
| receiver (pubkey) | 32 |
| amount (BE, in cents) | 8 |
| transaction fee (BE, in cents, can be zero) | 8 |
| signature (signed by sender, over transaction fields before signature) | 64 |

## transactions

For every block, the miner gets a reward of 1,00 cc. (100 cents)

If a transaction is included, the following happens additionally:

- The sender needs to pay "amount" + "transaction fee"
- The receiver gets "amount"
- The miner gets "transaction fee" on top of the reward.