SMC modification - stage 1

[hwwhww]

What is wrong?

Old sharding spec + A minimal sharding protocol

How can it be fixed

• "collator" -> "notary"
  • e.g., COLLATOR_DEPOSIT -> NOTARY_DEPOSIT
• Add constant
  • COMMITTEE_SIZE := 135
  • QUORUM_SIZE := 90

• Implement notary pool and notary registry:
  • register_notary() returns bool: Adds an entry to notary_registry, updates the notary pool (notary_pool, notary_pool_len, etc.), locks a deposit of size NOTARY_DEPOSIT, and returns True on success. Checks:
    • Deposit size: msg.value >= NOTARY_DEPOSIT
    • Uniqueness: notary_registry[msg.sender] does not exist
  • deregister_notary() returns bool: Sets the deregistered period in the notary_registry entry, updates the notary pool (notary_pool, notary_pool_len, etc.), and returns True on success. Checks:
    • Authentication: notary_registry[msg.sender] exists
  • release_natory() returns bool: Removes an entry from notary_registry, releases the notary deposit, and returns True on success. Checks:
    • Authentication: notary_registry[msg.sender] exists
    • Deregistered: notary_registry[msg.sender].deregistered != 0
    • Lockup: floor(block.number / PERIOD_LENGTH) > notary_registry[msg.sender].deregistered + NOTARY_LOCKUP_LENGTH

• add_header(shard_id, chunk_root, period) returns bool: anyone can call this function at anytime. The first header to get included for a given shard in a given period gets in, all others don’t. Returns True on success. This function just emits a log.

  • HeaderAdded log (emitted from SMC add_header function)
    • v1

    shard_id uint256  # pointer to shard
    chunk_root bytes32  # pointer to collation body
    period int128  # (current block number / PERIOD_LENGTH)
    proposer_address address  # the address of proposer

    • v2 compressed

    shard_id bytes1  # pointer to shard
    chunk_root bytes32  # pointer to collation body
    period bytes3  # (current block number / PERIOD_LENGTH)
    proposer_address address  # the address of proposer

• get_committee(shard_id, period) returns a list of addresses: use the last block hash h before this period as the seed. Selecting notary_pool[sha3(h) % notary_pool_size], notary_pool[sha3(h + 1) % notary_pool_size], .... notary_pool[sha3(h + (COMMITTEE_SIZE - 1)) % notary_pool_size] notaries from notary_pool.

• submit_vote(shard_id, chunk_root, period) returns bool: Sampled notaries call this function to submit vote, returns True on success. This function just emits a log.

  • Vote log (emitted from SMC submit_vote function)
    • v1

    shard_id uint256  # pointer to shard
    chunk_root bytes32 # pointer to collation body
    period int128  # (current block number / PERIOD_LENGTH)
    notary_address address  # the address of notary

    • v2 compressed

    shard_id bytes1  # pointer to shard
    chunk_root bytes32  # pointer to collation body
    period bytes3  # (current block number / PERIOD_LENGTH)
    notary_address address  # the address of notary

[hwwhww]

Latest discussion: https://ethresear.ch/t/minimal-sharding-protocol-extension/1823