How to create a genesis block (I'm starting an alt-chia)

juppin · June 23, 2021, 8:41am

Use your farmer and pool public key that should receive the prefarm and generate the puzzle hash with for example this tool:
https://www.chiaexplorer.com/tools/address-puzzlehash-converter

However, you should really consider not using a pre-farm as this will lower the acceptance of your fork in the community.

George · June 23, 2021, 8:47am

yes sir，this can generate GENESIS_PRE_FARM_POOL_PUZZLE_HASH and GENESIS_PRE_FARM_FARMER_PUZZLE_HASH，how about genesis challenge generate ？just random?

juppin · June 23, 2021, 9:10am

I would say this is random, every block in a block chain needs a hash that links it with the previous block and the first block (genesis block) need such a value too.

To mitigate some attacks like replay attack on other hard forks, you are advised to use a own genesis value for every hard fork!

On linux you would simply do something like:

$ dd if=/dev/urandom bs=1M count=1 2>/dev/null | sha256sum
c9fd4939f88dd9a171578e71ec98fb2c34d5bd9b4a832b1a8437f738f2c37f40

George · June 23, 2021, 9:11am

yes,i see, thank you very much,i will test it

juppin · June 23, 2021, 9:28am

Here are the proof that it’s really a sha256 value:

github.com

Chia-Network/chia-blockchain/blob/1.1.7/chia/consensus/block_creation.py#L236-L239

    
      
          if prev_transaction_block is None:
              prev_transaction_block_hash: bytes32 = constants.GENESIS_CHALLENGE
          else:
              prev_transaction_block_hash = prev_transaction_block.header_hash

github.com

Chia-Network/chia-blockchain/blob/b075e5bb8cfaf7d866a43201d6cc00646411e7d5/chia/types/full_block.py#L49

    
      
          
          
@property
          def weight(self):
              return self.reward_chain_block.weight
          
          
@property
          def total_iters(self):
              return self.reward_chain_block.total_iters
          
          
@property
          def header_hash(self):
              return self.foliage.get_hash()
          
          
def is_transaction_block(self) -> bool:
              return self.foliage_transaction_block is not None
          
          
def get_included_reward_coins(self) -> Set[Coin]:
              if not self.is_transaction_block():
                  return set()
              assert self.transactions_info is not None
              return set(self.transactions_info.reward_claims_incorporated)

github.com

Chia-Network/chia-blockchain/blob/b075e5bb8cfaf7d866a43201d6cc00646411e7d5/chia/util/streamable.py#L332

    
      
                  raise NotImplementedError(f"can't stream {item}, {f_type}")
          
          
def stream(self, f: BinaryIO) -> None:
              try:
                  fields = self.__annotations__  # pylint: disable=no-member
              except Exception:
                  fields = {}
              for f_name, f_type in fields.items():
                  self.stream_one_item(f_type, getattr(self, f_name), f)
          
          
def get_hash(self) -> bytes32:
              return bytes32(std_hash(bytes(self)))
          
          
@classmethod
          def from_bytes(cls: Any, blob: bytes) -> Any:
              f = io.BytesIO(blob)
              parsed = cls.parse(f)
              assert f.read() == b""
              return parsed
          
          
def __bytes__(self: Any) -> bytes:

github.com

Chia-Network/chia-blockchain/blob/b075e5bb8cfaf7d866a43201d6cc00646411e7d5/chia/util/hash.py#L6

    
      
          import blspy
          
          
from chia.types.blockchain_format.sized_bytes import bytes32
          
          

          
def std_hash(b) -> bytes32:
              """
              The standard hash used in many places.
              """
              return bytes32(blspy.Util.hash256(bytes(b)))

github.com

Chia-Network/bls-signatures/blob/6aca6349bd6c8ed369672307885df33cdcd124f9/python-impl/util.py#L9

    
      
          import hashlib
          
          
HMAC_BLOCK_SIZE = 64
          
          

          
def hash256(m):
              if type(m) != bytes:
                  m = m.encode("utf-8")
              return hashlib.sha256(m).digest()
          
          

          
def hash512(m):
              if type(m) != bytes:
                  m = m.encode("utf-8")
              return hash256(m + bytes([0])) + hash256(m + bytes([1]))
          
          

          
def hmac256(m, k):
              if type(m) != bytes and type(m) != bytearray:

George · June 24, 2021, 9:53am

Azile · June 24, 2021, 9:57am

Honestly, it is very hard for anyone to help troubleshoot this because they need to know very specifically each and every step you took in setting all this up. Step by step, what did you do, what did you edit, what order did you start everything up, how you are adding IPs and such. Is your fork on github so we can see and so on.

You could be trying to solve one issue but in all reality it is another entirely. So share as much details as possible as to how you did everything to get to this point.

George · June 24, 2021, 10:10am

yes，it is hard to say my detail operation，
first I fork chia,
chage port in config,
change GENESIS challenge and two PUZZLE_HASH,
build and run(three client, unbutun and win,all service start in unbutun include timelord)
genesis block hadn’t auto generate ，the height is still zero，status is Not Synced.

ChiaMax · June 24, 2021, 10:12am

Start by making your constants like flax:

github.com

Flax-Network/flax-blockchain/blob/b61980cee6da1cb49c040318b5ce62b55b108a09/flax/consensus/default_constants.py

from flax.util.ints import uint64

from .constants import ConsensusConstants

testnet_kwargs = {
    "SLOT_BLOCKS_TARGET": 32,
    "MIN_BLOCKS_PER_CHALLENGE_BLOCK": 16,  # Must be less than half of SLOT_BLOCKS_TARGET
    "MAX_SUB_SLOT_BLOCKS": 128,  # Must be less than half of SUB_EPOCH_BLOCKS
    "NUM_SPS_SUB_SLOT": 64,  # Must be a power of 2
    "SUB_SLOT_ITERS_STARTING": 2 ** 27,
    # DIFFICULTY_STARTING is the starting difficulty for the first epoch, which is then further
    # multiplied by another factor of DIFFICULTY_CONSTANT_FACTOR, to be used in the VDF iter calculation formula.
    "DIFFICULTY_CONSTANT_FACTOR": 2 ** 57,
    "DIFFICULTY_STARTING": 7,
    "DIFFICULTY_CHANGE_MAX_FACTOR": 3,  # The next difficulty is truncated to range [prev / FACTOR, prev * FACTOR]
    # These 3 constants must be changed at the same time
    "SUB_EPOCH_BLOCKS": 384,  # The number of blocks per sub-epoch, mainnet 384
    "EPOCH_BLOCKS": 4608,  # The number of blocks per epoch, mainnet 4608. Must be multiple of SUB_EPOCH_SB
    "SIGNIFICANT_BITS": 8,  # The number of bits to look at in difficulty and min iters. The rest are zeroed
    "DISCRIMINANT_SIZE_BITS": 1024,  # Max is 1024 (based on ClassGroupElement int size)

This file has been truncated. show original

ChiaMax · June 24, 2021, 10:15am

you can change
“MIN_PLOT_SIZE”: 32, # 32 for mainnet

to a lower plot value, then create a lot of small sized plots for testing.
remember that the plot filter is 1/512 so you need a good amount of plots to get at least a few to pass filter.

ChiaMax · June 24, 2021, 10:18am

aren’t you trying to get a testnet running

I’m saying flax is the fork with least amount changed… their constants have the correct values… if you copy theirs, you eliminate any issues due to bad constant values.

you should really understand what each constant value does, but this will give you a quick path to getting a fork up.

George · June 24, 2021, 10:20am

thank you sir ,i will try to used flax code,may be it works

George · June 24, 2021, 12:02pm

hi,sir,i used flax code,but look the same.
i fork flax code,and change port,
no change to genesis challenge and prefarm puzzle hash.
used two client(linux run all service,win run client)
but no genesis block auto generate,so where am i wrong?

two fullnode add each other

ChiaMax · June 24, 2021, 12:10pm

Full nodes can be timelords or farmers, or they can just perform the roles of a full node. This entails broadcasting proofs of space and time, creating blocks, maintaining a mempool of pending transactions, storing the historical blockchain, and uploading blocks to other full nodes as well as wallets (light clients).

Are you running the 3 timelord VDFs ?

George · June 24, 2021, 12:12pm

yes，linux start all service

George · June 24, 2021, 12:15pm

am i ask a question? the first block(genesis block) is auto generate? or generate by function in code then broadcast
by the way,i had not run testnet,i change the mainnet port

ChiaMax · June 24, 2021, 12:15pm

Check if the farmer: creates a proof of Space
Check if the timelord: creates a proof of Time
by checking if the challenge chain advances

I can’t debug this for you… open the logs check out the block verification part (header and block content), there are many things that can abort block creation

George · June 24, 2021, 12:18pm

the debug log like this

ChiaMax · June 24, 2021, 12:57pm

github.com

Chia-Network/chia-blockchain/blob/79bc40f1d69d267caf84ea8dd579bcfc552780fb/chia/timelord/timelord.py

import asyncio
import dataclasses
import io
import logging
import random
import time
import traceback
from typing import Callable, Dict, List, Optional, Tuple, Set

from chiavdf import create_discriminant

from chia.consensus.constants import ConsensusConstants
from chia.consensus.pot_iterations import calculate_sp_iters, is_overflow_block
from chia.protocols import timelord_protocol
from chia.protocols.protocol_message_types import ProtocolMessageTypes
from chia.server.outbound_message import NodeType, make_msg
from chia.server.server import ChiaServer
from chia.timelord.iters_from_block import iters_from_block
from chia.timelord.timelord_state import LastState
from chia.timelord.types import Chain, IterationType, StateType

This file has been truncated. show original

your turn to debug this… if you can’t read the code or figure this out… a fork is simply not for you.

hivecoin2021 · June 24, 2021, 5:28pm

Yes
1 you need change this 60 to 600 seconds.
2 you need prepare more than 100 100G (10T)plots to boot up.
3 if you not have enough plots, you can change the NUMBER_ZERO_BITS_PLOT_FILTER value to 1 in default_constants.py file.

this steps base on you work before.

you will get your genesis block in half hour.

Good luck.