denaro

denaro, 'money' in italian, is a cryptocurrency written in Python.
Maximum supply is 30.062.005.
Maximum decimal digits count is 6.
Blocks are generated every ~3 minutes, with a limit of 1000 transactions per block, and a limit of 2048 bytes per transaction.
This makes possible to handle ~5 transactions per second, with a maximum block size of 2000kb.

Installation

Before installing denaro, you need to create the postgresql database.
You can find the schema in schema.sql.
You have to set environmental variables for database access:

• DENARO_DATABASE_USER, default to denaro.
• DENARO_DATABASE_PASSWORD, default to an empty string.
• DENARO_DATABASE_NAME, default to denaro.
• DENARO_DATABASE_HOST, default to 127.0.0.1.

# install postgresql
createdb denaro
psql -d denaro
## paste content of schema.sql

Then install denaro.

git clone https://github.com/denaro-coin/denaro
cd denaro
pip3 install -r requirements.txt
uvicorn denaro.node.main:app --port 3006 --workers 2

Node should now sync the blockchain and start working

Mining

denaro uses a PoW system.

Block hash is the sha256 of raw bytes of previous_hash, public_key, merkle_tree, timestamp, difficulty, random, for example 387389eb614db0e3ada0af248f2f0adac12db35963f4bbdd71ef14914e8ade81dbda85e237b90aa669da00f2859e0010b0a62e0fb6e55ba6ca3ce8a961a60c64410bcfb6a038310a3bb6f1a4aaa2de1192cc10e380a774bb6f9c6ca8547f11abe3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b8556662796132007d521100
The derived sha256 must start with the last difficulty characters (hex) of the previous mined block.
random must be at most 4 bytes long.
difficulty can also have decimal digits (in block it is in fact difficulty * 10, 2 bytes long), that will restrict the difficulty + 1th character of the derived sha to have a limited set of values.

from math import ceil

difficulty = 6.3
decimal = difficulty % 1

charset = '0123456789abcdef'
count = ceil(16 * (1 - decimal))
allowed_characters = charset[:count]

Address must be present in the string in order to ensure block property.

Blocks have a block reward that will half itself til it reaches 0.
There will be 150000 blocks with reward 100, and so on til 0.390625, which will last 458732 blocks.
The last block with a reward will be the 458733th, with a reward of 0.3125.
Subsequent blocks won't have a block reward.
Reward will be added the fees of the transactions included in the block.
A transaction may also have no fees at all.