tersec
GitHub
commit
41d45d4a67
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@ -21,6 +21,36 @@ import milagro_crypto
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# - Signature (48 bytes - 384-bit)
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# - VerKey (public key) (192 bytes)
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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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MIN_ONLINE_DEPOSIT_SIZE* = 2^4 # ETH
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GWEI_PER_ETH* = 10^9 # Gwei/ETH
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TARGET_COMMITTEE_SIZE* = 2^8 # validators
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SLOT_DURATION* = 6 # seconds
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CYCLE_LENGTH* = 64 # slots (~ 6 minutes)
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MIN_VALIDATOR_SET_CHANGE_INTERVAL* = 2^8 # slots (~25 minutes)
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SHARD_PERSISTENT_COMMITTEE_CHANGE_PERIOD* = 2^17 # slots (~9 days)
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MIN_ATTESTATION_INCLUSION_DELAY* = 2^2 # slots (~25 minutes)
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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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WITHDRAWALS_PER_CYCLE* = 2^2 # validators (5.2m ETH in ~6 months)
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MIN_WITHDRAWAL_PERIOD* = 2^13 # slots (~14 hours)
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DELETION_PERIOD* = 2^22 # slots (~290 days)
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COLLECTIVE_PENALTY_CALCULATION_PERIOD* = 2^20 # slots (~2.4 months)
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SLASHING_WHISTLEBLOWER_REWARD_DENOMINATOR* = 2^9 # ?
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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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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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POW_HASH_VOTING_PERIOD* = 2^10 # ?
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POW_CONTRACT_MERKLE_TREE_DEPTH* = 2^5 #
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INITIAL_FORK_VERSION* = 0 # currently behaves like a constant
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type
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# Alias
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BLSPublicKey* = VerKey
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@ -98,8 +128,10 @@ type
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last_finalized_slot*: uint64 # Last finalized slot
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last_justified_slot*: uint64 # Last justified slot
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justified_streak*: uint64 # Number of consecutive justified slots
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shard_and_committee_for_slots*: seq[ShardAndCommittee] # Committee members and their assigned shard, per slot
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persistent_committees*: Uint24 # Persistent shard committees
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shard_and_committee_for_slots*: array[2 * CYCLE_LENGTH, seq[ShardAndCommittee]] ## \
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## Committee members and their assigned shard, per slot, covers 2 cycles
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## worth of assignments
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persistent_committees*: seq[seq[ValidatorRecord]] # Persistent shard committees
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persistent_committee_reassignments*: seq[ShardReassignmentRecord]
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next_shuffling_seed*: Blake2_256_Digest # Randao seed used for next shuffling
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deposits_penalized_in_period*: uint32 # Total deposits penalized in the given withdrawal period
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@ -127,6 +159,13 @@ type
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exit_slot*: uint64 # Slot when validator exited (or 0)
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exit_seq*: uint64 # Sequence number when validator exited (or 0)
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InitialValidator* = object
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pubkey*: BLSPublicKey
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proof_of_possession*: seq[byte]
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withdrawal_shard*: uint16
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withdrawal_address*: EthAddress
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randao_commitment*: Blake2_256_Digest
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ValidatorStatusCodes* {.pure.} = enum
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PendingActivation = 0
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Active = 1
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@ -157,31 +196,3 @@ type
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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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@ -8,43 +8,42 @@
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# Helper functions
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import ../datatypes, sequtils, nimcrypto, math
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func get_active_validator_indices(validators: seq[ValidatorRecord]): seq[Uint24] =
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## Select the active validators
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result = @[]
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for idx, val in validators:
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if val.status == ACTIVE:
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result.add idx.Uint24
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func shuffle(values: seq[Uint24], seed: Blake2_256_Digest): seq[Uint24] {.noInit.}=
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func shuffle*[T](values: seq[T], seed: Blake2_256_Digest): seq[T] =
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## Returns the shuffled ``values`` with seed as entropy.
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## TODO: this calls out for tests, but I odn't particularly trust spec
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## right now.
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let values_count = values.len
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# Entropy is consumed from the seed in 3-byte (24 bit) chunks
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const rand_bytes = 3
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let rand_max = 2^(rand_bytes * 8) - 1
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const
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# Entropy is consumed from the seed in 3-byte (24 bit) chunks.
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rand_bytes = 3
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# The highest possible result of the RNG.
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rand_max = 2^(rand_bytes * 8) - 1
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# The range of the RNG places an upper-bound on the size of the list that
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# may be shuffled. It is a logic error to supply an oversized list.
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assert values_count < rand_max
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deepCopy(result, values)
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var source = seed
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var i = 0
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while i < values.len - 1:
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# Re-hash the `source` to obtain a new pattern of bytes
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result = values
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var
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source = seed
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index = 0
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while index < values_count - 1:
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# Re-hash the `source` to obtain a new pattern of bytes.
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source = blake2_256.digest source.data
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# Iterate through the `source` bytes in 3-byte chunks
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# Iterate through the `source` bytes in 3-byte chunks.
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for pos in countup(0, 29, 3):
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let remaining = values_count - i
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let remaining = values_count - index
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if remaining == 1:
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break
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# Read 3-bytes of `source` as a 24-bit big-endian integer.
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let sample_from_source = source.data[pos].Uint24 shl 16 or source.data[pos+1].Uint24 shl 8 or source.data[pos+2].Uint24
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let sample_from_source =
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source.data[pos].Uint24 shl 16 or
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source.data[pos+1].Uint24 shl 8 or
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source.data[pos+2].Uint24
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# Sample values greater than or equal to `sample_max` will cause
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# modulo bias when mapped into the `remaining` range.
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@ -52,58 +51,27 @@ func shuffle(values: seq[Uint24], seed: Blake2_256_Digest): seq[Uint24] {.noInit
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# Perform a swap if the consumed entropy will not cause modulo bias.
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if sample_from_source < sample_max:
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let replacement_position = sample_from_source mod remaining + i
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swap result[i], result[replacement_position]
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inc i
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# Select a replacement index for the current index.
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let replacement_position = sample_from_source mod remaining + index
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swap result[index], result[replacement_position]
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inc index
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func split[T](lst: seq[T], N: Positive): seq[seq[T]] =
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func split*[T](lst: openArray[T], N: Positive): seq[seq[T]] =
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## split lst in N pieces, with each piece having `len(lst) div N` or
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## `len(lst) div N + 1` pieces
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# TODO: implement as an iterator
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result = newSeq[seq[T]](N)
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for i in 0 ..< N:
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result[i] = lst[lst.len * i div N ..< lst.len * (i+1) div N] # TODO: avoid alloc via toOpenArray
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func get_new_shuffling*(seed: Blake2_256_Digest, validators: seq[ValidatorRecord],
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dynasty: int64, crosslinking_start_shard: int16): seq[seq[ShardAndCommittee]] {.noInit.} =
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## Split up validators into groups at the start of every epoch,
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## determining at what height they can make attestations and what shard they are making crosslinks for
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## Implementation should do the following: http://vitalik.ca/files/ShuffleAndAssign.png
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let avs = get_active_validator_indices(validators)
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var committees_per_slot, slots_per_committee: uint16
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if avs.len >= CYCLE_LENGTH * MIN_COMMITTEE_SIZE:
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committees_per_slot = uint16 avs.len div CYCLE_LENGTH div (MIN_COMMITTEE_SIZE * 2) + 1
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slots_per_committee = 1
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else:
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committees_per_slot = 1
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slots_per_committee = 1
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while avs.len.uint16 * slots_per_committee < CYCLE_LENGTH * MIN_COMMITTEE_SIZE and
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slots_per_committee < CYCLE_LENGTH:
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slots_per_committee *= 2
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result = @[]
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for slot, slot_indices in shuffle(avs, seed).split(CYCLE_LENGTH):
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let shard_indices = slot_indices.split(committees_per_slot)
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let shard_id_start = crosslinking_start_shard.uint16 +
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slot.uint16 * committees_per_slot div slots_per_committee
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var committees = newSeq[ShardAndCommittee](shard_indices.len)
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for j, indices in shard_indices:
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committees[j].shard_id = (shard_id_start + j.uint16) mod SHARD_COUNT
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committees[j].committee = indices
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result.add committees
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func get_shards_and_committees_for_slot*(state: BeaconState,
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slot: uint64): seq[ShardAndCommittee] =
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# TODO: Spec why is active_state an argument?
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# TODO: this returns a scalar, not vector, but its return type in spec is a seq/list?
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slot: uint64
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): seq[ShardAndCommittee] =
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let earliest_slot_in_array = state.last_state_recalculation_slot - CYCLE_LENGTH
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assert earliest_slot_in_array <= slot
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assert slot < earliest_slot_in_array + CYCLE_LENGTH * 2
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return @[state.shard_and_committee_for_slots[int slot - earliest_slot_in_array]]
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return state.shard_and_committee_for_slots[int slot - earliest_slot_in_array]
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# TODO, slot is a uint64; will be an issue on int32 arch.
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# Clarify with EF if light clients will need the beacon chain
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@ -114,11 +82,10 @@ func get_block_hash*(state: BeaconState, current_block: BeaconBlock, slot: int):
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return state.recent_block_hashes[slot - earliest_slot_in_array]
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func get_new_recent_block_hashes*(
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old_block_hashes: seq[Blake2_256_Digest],
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parent_slot, current_slot: int64,
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parent_hash: Blake2_256_Digest
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): seq[Blake2_256_Digest] =
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func get_new_recent_block_hashes*(old_block_hashes: seq[Blake2_256_Digest],
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parent_slot, current_slot: int64,
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parent_hash: Blake2_256_Digest
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): seq[Blake2_256_Digest] =
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# Should throw for `current_slot - CYCLE_LENGTH * 2 - 1` according to spec comment
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let d = current_slot - parent_slot
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@ -126,3 +93,16 @@ func get_new_recent_block_hashes*(
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for _ in 0 ..< min(d, old_block_hashes.len):
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result.add parent_hash
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func get_beacon_proposer*(state: BeaconState, slot: uint64): ValidatorRecord =
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## From Casper RPJ mini-spec:
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## When slot i begins, validator Vidx is expected
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## to create ("propose") a block, which contains a pointer to some parent block
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## that they perceive as the "head of the chain",
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## and includes all of the **attestations** that they know about
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## that have not yet been included into that chain.
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##
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## idx in Vidx == p(i mod N), pi being a random permutation of validators indices (i.e. a committee)
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let
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first_committee = get_shards_and_committees_for_slot(state, slot)[0].committee
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index = first_committee[(slot mod len(first_committee).uint64).int]
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state.validators[index]
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@ -0,0 +1,94 @@
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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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# Helpers and functions pertaining to managing the validator set
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import
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options,
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eth_common, nimcrypto/blake2,
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./datatypes, ./private/helpers
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func min_empty_validator(validators: seq[ValidatorRecord], current_slot: uint64): Option[int] =
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for i, v in validators:
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if v.status == WITHDRAWN and v.exit_slot + DELETION_PERIOD.uint64 <= current_slot:
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return some(i)
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func add_validator*(validators: var seq[ValidatorRecord],
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pubkey: BLSPublicKey,
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proof_of_possession: seq[byte],
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withdrawal_shard: uint16,
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withdrawal_address: EthAddress,
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randao_commitment: Blake2_256_Digest,
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status: ValidatorStatusCodes,
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current_slot: uint64
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): int =
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# Check that validator really did register
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# let signed_message = as_bytes32(pubkey) + as_bytes2(withdrawal_shard) + withdrawal_address + randao_commitment
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# assert BLSVerify(pub=pubkey,
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# msg=hash(signed_message),
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# sig=proof_of_possession)
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# Pubkey uniqueness
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# assert pubkey not in [v.pubkey for v in validators]
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let
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rec = ValidatorRecord(
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pubkey: pubkey,
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withdrawal_shard: withdrawal_shard,
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withdrawal_address: withdrawal_address,
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randao_commitment: randao_commitment,
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randao_last_change: current_slot,
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balance: DEPOSIT_SIZE * GWEI_PER_ETH,
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status: status,
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exit_slot: 0,
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exit_seq: 0
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)
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let index = min_empty_validator(validators, current_slot)
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if index.isNone:
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validators.add(rec)
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return len(validators) - 1
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else:
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validators[index.get()] = rec
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return index.get()
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func get_active_validator_indices(validators: openArray[ValidatorRecord]): seq[Uint24] =
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## Select the active validators
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result = @[]
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for idx, val in validators:
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if val.status == ACTIVE:
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result.add idx.Uint24
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func get_new_shuffling*(seed: Blake2_256_Digest,
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validators: openArray[ValidatorRecord],
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crosslinking_start_shard: int
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): array[CYCLE_LENGTH, seq[ShardAndCommittee]] =
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## Split up validators into groups at the start of every epoch,
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## determining at what height they can make attestations and what shard they are making crosslinks for
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## Implementation should do the following: http://vitalik.ca/files/ShuffleAndAssign.png
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let
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active_validators = get_active_validator_indices(validators)
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committees_per_slot = clamp(
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len(active_validators) div CYCLE_LENGTH div TARGET_COMMITTEE_SIZE,
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1, SHARD_COUNT div CYCLE_LENGTH)
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# Shuffle with seed
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shuffled_active_validator_indices = shuffle(active_validators, seed)
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# Split the shuffled list into cycle_length pieces
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validators_per_slot = split(shuffled_active_validator_indices, CYCLE_LENGTH)
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assert validators_per_slot.len() == CYCLE_LENGTH # what split should do..
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for slot, slot_indices in validators_per_slot:
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let
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shard_indices = split(slot_indices, committees_per_slot)
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shard_id_start = crosslinking_start_shard + slot * committees_per_slot
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var committees = newSeq[ShardAndCommittee](shard_indices.len)
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for shard_position, indices in shard_indices:
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committees[shard_position].shard_id = (shard_id_start + shard_position).uint16 mod SHARD_COUNT
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committees[shard_position].committee = indices
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result[slot] = committees
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@ -6,5 +6,6 @@
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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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import
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./test_block_processing,
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./test_ssz,
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./test_block_processing
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./test_validator
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@ -0,0 +1,31 @@
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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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import
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math, nimcrypto, unittest, sequtils,
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../beacon_chain/[datatypes, validator]
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func sumCommittees(v: openArray[seq[ShardAndCommittee]]): int =
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for x in v:
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for y in x:
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inc result, y.committee.len
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suite "Validators":
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## For now just test that we can compile and execute block processing with mock data.
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## https://github.com/status-im/nim-beacon-chain/issues/1
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## https://github.com/sigp/lighthouse/blob/ba548e49a52687a655c61b443b6835d79c6d4236/beacon_chain/validator_shuffling/src/shuffle.rs
|
||||
test "Smoke validator shuffling":
|
||||
let
|
||||
validators = repeat(
|
||||
ValidatorRecord(
|
||||
status: ACTIVE
|
||||
), 1024)
|
||||
|
||||
# XXX the shuffling looks really odd, probably buggy
|
||||
let s = get_new_shuffling(Blake2_256_Digest(), validators, 0)
|
||||
check:
|
||||
s.len == CYCLE_LENGTH
|
||||
sumCommittees(s) == validators.len() # all validators accounted for
|
||||
Loading…
Reference in New Issue