159 lines
8.4 KiB
Nim
159 lines
8.4 KiB
Nim
# beacon_chain
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# Copyright (c) 2018 Status Research & Development GmbH
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# Licensed and distributed under either of
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# * MIT license (license terms in the root directory or at http://opensource.org/licenses/MIT).
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# * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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# In process of being updated as of spec from 2018-11-05
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# https://github.com/ethereum/eth2.0-specs/tree/59f32978d489020770ae50e6d45450103445c6ad
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#
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# The latest version can be seen here:
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# https://github.com/ethereum/eth2.0-specs/blob/master/specs/beacon-chain.md
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#
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# How wrong the code is:
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# https://github.com/ethereum/eth2.0-specs/compare/59f32978d489020770ae50e6d45450103445c6ad...master
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import
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intsets, eth_common, math, stint
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import milagro_crypto
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# nimble install https://github.com/status-im/nim-milagro-crypto@#master
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# Defines
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# - SigKey (private/secret key) (48 bytes)
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# - Signature and AggregatedSignature (97 bytes)
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# - VerKey (public key) and AggregatedVerKey (192 bytes)
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type
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# Alias
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BLSPublicKey* = VerKey
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BLSsig* = Signature
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BLSaggregateSig* = AggregatedSignature
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Blake2_256_Digest* = Hash256 # TODO change to Blake2b-512[0 ..< 32] see https://github.com/status-im/nim-beacon-chain/issues/3
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Uint24* = range[0'u32 .. 0xFFFFFF'u32] # TODO: wrap-around
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SpecialRecord* = object
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kind*: SpecialRecordTypes # Kind
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data*: seq[byte] # Data
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BeaconBlock* = object
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slot*: uint64 # Slot number
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randao_reveal*: Blake2_256_Digest # Proposer RANDAO reveal
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pow_chain_reference*: Blake2_256_Digest # Recent PoW chain reference (block hash)
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ancestor_hashes*: seq[Blake2_256_Digest] # Skip list of previous beacon block hashes
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# i'th item is most recent ancestor whose
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# slot is a multiple of 2**i for
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# i == 0, ..., 31
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active_state_root*: Blake2_256_Digest # Hash of the active state
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crystallized_state_root*: Blake2_256_Digest # Hash of the crystallized state
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attestations*: seq[AttestationRecord] # Attestation votes
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parent_hash*: Blake2_256_Digest # Hash of the parent block
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ActiveState* = object
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pending_attestations*: seq[AttestationRecord] # Attestations that have not yet been processed
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recent_block_hashes*: seq[Blake2_256_Digest] # Most recent 2 * CYCLE_LENGTH block hashes, older to newer
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CrystallizedState* = object
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validators*: seq[ValidatorRecord] # List of active validators
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last_state_recalc*: uint64 # Last CrystallizedState recalculation
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shard_and_committee_for_slots*: seq[seq[ShardAndCommittee]]
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# What active validators are part of the attester set
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# at what height, and in what shard. Starts at slot
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# last_state_recalc - CYCLE_LENGTH
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last_justified_slot*: int64 # The last justified slot
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justified_streak*: int16 # Number of consecutive justified slots ending at this one
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last_finalized_slot*: int64 # The last finalized slot
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current_dynasty*: int64 # The current dynasty
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crosslink_records*: seq[CrosslinkRecord] # Records about the most recent crosslink for each shard
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dynasty_seed*: Blake2_256_Digest # Used to select the committees for each shard
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dynasty_seed_last_reset*: int64 # Last epoch the crosslink seed was reset
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ShardAndCommittee* = object
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shard_id*: int16 # The shard ID
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committee*: seq[Uint24] # Validator indices
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ValidatorRecord* = object
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pubkey*: BLSPublicKey # The validator's public key
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withdrawal_shard*: int16 # What shard the validator's balance will be sent to after withdrawal
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withdrawal_address*: EthAddress # And what address
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randao_commitment*: Blake2_256_Digest # The validator's current RANDAO beacon commitment
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balance*: Int128 # Current balance
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start_dynasty*: int64 # Dynasty where the validator is inducted
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end_dynasty*: int64 # Dynasty where the validator leaves
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CrosslinkRecord* = object
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dynasty: int64 # What dynasty the crosslink was submitted in
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slot: int64 # What slot
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hash: Blake2_256_Digest # The block hash
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AttestationRecord* = object
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slot*: int64 # Slot number
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shard_id*: int16 # Shard ID
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oblique_parent_hashes*: seq[Blake2_256_Digest]
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# List of block hashes that this signature is signing over that
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# are NOT part of the current chain, in order of oldest to newest
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shard_block_hash*: Blake2_256_Digest # Block hash in the shard that we are attesting to
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attester_bitfield*: IntSet # Who is participating
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justified_slot*: int64
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justified_block_hash: Blake2_256_Digest
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aggregate_sig*: BLSaggregateSig # The actual signature
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ValidatorStatusCodes* {.pure.} = enum
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PendingActivation = 0
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Active = 1
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PendingExit = 2
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PendingWithdraw = 3
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Withdrawn = 4
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Penalized = 127
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SpecialRecordTypes* {.pure.} = enum
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Logout = 0
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CasperSlashing = 1
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RandaoChange = 2
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ValidatorSetDeltaFlags* {.pure.} = enum
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Entry = 0
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Exit = 1
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# Note:
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# We use IntSet from Nim Standard library which are efficient sparse bitsets.
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# See: https://nim-lang.org/docs/intsets.html
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#
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# Future:
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# IntSets stores the first 34 elements in an array[34, int] instead of a bitfield
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# to avoid heap allocation in profiled common cases.
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#
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# In Ethereum we probably always have over 34 attesters given the goal of decentralization.
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# Allocating 8 * 34 = 272 bytes on the stack is wasteful, when this can be packed in just 8 bytes
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# with room to spare.
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#
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# Also, IntSets uses machine int size while we require int64 even on 32-bit platform.
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const
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SHARD_COUNT* = 1024 # a constant referring to the number of shards
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DEPOSIT_SIZE* = 2^5 # You need to deposit 32 ETH to be a validator in Casper
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SLOT_DURATION* = 16 # seconds
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CYCLE_LENGTH* = 64 # slots
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MIN_COMMITTEE_SIZE* = 2^7 # validators; 2018-11-05 version of spec also says:
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# See a recommended `MIN_COMMITTEE_SIZE` of 111 here
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# https://vitalik.ca/files/Ithaca201807_Sharding.pdf).
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SQRT_E_DROP_TIME* = 2^16 # slots (~12 days); amount of time it takes for the
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# quadratic leak to cut deposits of non-participating
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# validators by ~39.4%
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BASE_REWARD_QUOTIENT* = 2^15 # per-slot interest rate assuming all validators are
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# participating, assuming total deposits of 1 ETH. It
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# corresponds to ~3.88% annual interest assuming 10
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# million participating ETH.
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MIN_BALANCE* = 2^4 # ETH
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MIN_ONLINE_DEPOSIT_SIZE* = 2^4 # ETH
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GWEI_PER_ETH* = 10^9 # Gwei/ETH
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MIN_VALIDATOR_SET_CHANGE_INTERVAL* = 2^8 # slots (~1.1 hours)
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RANDAO_SLOTS_PER_LAYER* = 2^12 # slots (~18 hours)
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WITHDRAWAL_PERIOD* = 2^19 # slots (~97 days)
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SHARD_PERSISTENT_COMMITTEE_CHANGE_PERIOD* = 2^16 # slots (~12 days)
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MAX_VALIDATOR_CHURN_QUOTIENT* = 2^5 # At most `1/MAX_VALIDATOR_CHURN_QUOTIENT` of the
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# validators can change during each validator set
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# change.
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INITIAL_FORK_VERSION* = 0 # currently behaves like a constant
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