beacon: move beacon-chain to geth-sharding repo (#250)

Former-commit-id: 689de6935d724226eb9125d597831d7b274d79c1 [formerly 4e0c0d671c4e6284cd33300231cc0f7aba99d314]
Former-commit-id: c3079b352bc938c12708b81cdc0130909456ea27

beacon-chain/BUILD.bazel

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+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["config.go"],
+    importpath = "github.com/prysmaticlabs/geth-sharding/beacon-chain",
+    visibility = ["//visibility:public"],
+)

beacon-chain/LICENSE.md

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+MIT License
+
+Copyright (c) 2018 Prysmatic Labs
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

beacon-chain/README.md

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+# Prysmatic Labs Beacon Chain Implementation
+
+This is the main repository for the beacon chain implementation of Ethereum 2.0 in Golang by [Prysmatic Labs](https://prysmaticlabs.com). Before you begin, check out our [Contribution Guidelines](#contribution-guidelines) and join our active chat room on Gitter below:
+
+[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/prysmaticlabs/geth-sharding?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
+
+Also, read the latest sharding + casper [design spec](https://ethresear.ch/t/convenience-link-to-full-casper-chain-v2-spec/2332), this design spec serves as a source of truth for the beacon chain implementation we follow at prysmatic labs.
+Refer this page on [why](http://email.mg2.substack.com/c/eJwlj9GOhCAMRb9G3jRQQPGBh5mM8xsbhKrsDGIAM9m_X9xN2qZtbpt7rCm4xvSjj5gLOTOmL-809CMbKXFaOKakIl4DZYr2AGyQIGjHOnWH22OiYnoIxmDijaBhhS6fcy7GvjobA9m0mSXOcnZq5GBqLkilXBZhBsus5ZK89VbKkRt-a-BZI6DzZ7iur1lQ953KJ9bemnxgahuQU9XJu6pFPdu8meT8vragzEjpMCwMGLlgLo6h5z1JumQTu4IJd4v15xqMf_8ZLP_Y1bSLdbnrD-LL71i2Kj7DLxaWWF4)
+we are comibing sharding and casper together.

beacon-chain/config.go

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+package beacon
+
+const (
+	// AttesterCount is the number of attesters per committee/
+	AttesterCount = 32
+	// AttesterReward determines how much ETH attesters get for performing their duty.
+	AttesterReward = 1
+	// EpochLength is the beacon chain epoch length in blocks.
+	EpochLength = 5
+	// ShardCount is a fixed number.
+	ShardCount = 20
+	// DefaultBalance of a validator.
+	DefaultBalance = 32000
+	// DefaultSwitchDynasty value.
+	DefaultSwitchDynasty = 9999999999999999999
+	// MaxValidators in the protocol.
+	MaxValidators = 2 ^ 24
+	// NotariesPerCrosslink fixed to 100.
+	NotariesPerCrosslink = 100
+)

beacon-chain/types/BUILD.bazel

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+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "block.go",
+        "state.go",
+    ],
+    importpath = "github.com/prysmaticlabs/geth-sharding/beacon-chain/types",
+    visibility = ["//visibility:public"],
+    deps = ["@com_github_ethereum_go_ethereum//common:go_default_library"],
+)

beacon-chain/types/block.go

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+package types
+
+import "github.com/ethereum/go-ethereum/common"
+
+// Header contains the block header fields in beacon chain.
+type Header struct {
+	ParentHash              common.Hash     // ParentHash is the hash of the parent beacon block.
+	SkipCount               uint64          // SkipCount is the number of skips, this is used for the full PoS mechanism.
+	RandaoReveal            common.Hash     // RandaoReveal is used for Randao commitment reveal.
+	AttestationBitmask      []byte          // AttestationBitmask is the bit field of who from the attestation committee participated.
+	AttestationAggregateSig []uint          // AttestationAggregateSig is validator's aggregate sig.
+	ShardAggregateVotes     []AggregateVote // ShardAggregateVotes is shard aggregate votes.
+	MainChainRef            common.Hash     // MainChainRef is the reference to main chain block.
+	StateHash               []byte          // StateHash is the concatenation of crystallized and active state.
+	Sig                     []uint          // Sig is the signature of the proposer.
+}
+
+// AggregateVote contains the fields of aggregate vote in individual shard.
+type AggregateVote struct {
+	ShardID        uint16      // Shard ID of the voted shard.
+	ShardBlockHash common.Hash // ShardBlockHash is the shard block hash of the voted shard.
+	SignerBitmask  []byte      // SignerBitmask is the bit mask of every validator that signed.
+	AggregateSig   []uint      // AggregateSig is the aggregated signatures of individual shard.
+}

beacon-chain/types/state.go

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+package types
+
+import (
+	"crypto/ecdsa"
+
+	"github.com/ethereum/go-ethereum/common"
+)
+
+// ActiveState contains fields of current state of beacon chain,
+// it changes every block.
+type ActiveState struct {
+	Height            uint64                   // Height of the current block.
+	Randao            common.Hash              // Randao beacon state from global's point of view.
+	FfgVoterBitmask   []byte                   // FfgVoterBitmask records the validators that voted for this epoch as bitfield.
+	BalanceDeltas     []uint                   // BalanceDeltas is the deltas to validator balances.
+	PartialCrosslinks []PartialCrosslinkRecord // PartialCrosslinks records data about crosslinks in progress.
+	TotalSkipCount    uint64                   // TotalSkipCount records total number of skips to determine minimal time stamp.
+}
+
+// PartialCrosslinkRecord contains information about cross links
+// that are being put together during this epoch.
+type PartialCrosslinkRecord struct {
+	ShardID        uint16      // ShardID is the shard crosslink being made for.
+	ShardBlockHash common.Hash // ShardBlockHash is the hash of the block.
+	VoterBitmask   []byte      // VoterBitmask determines which of the eligible voters are voting for it.
+}
+
+// CrystallizedState contains fields of every epoch state,
+// it changes every epoch.
+type CrystallizedState struct {
+	ActiveValidators       []ValidatorRecord // ActiveValidators is the list of active validators.
+	QueuedValidators       []ValidatorRecord // QueuedValidators is the list of joined but not yet inducted validators.
+	ExitedValidators       []ValidatorRecord // ExitedValidators is the list of removed validators pending withdrawal.
+	CurrentShuffling       []uint16          // CurrentShuffling is hhe permutation of validators used to determine who cross-links what shard in this epoch.
+	CurrentEpoch           uint64            // CurrentEpoch is the current epoch.
+	LastJustifiedEpoch     uint64            // LastJustifiedEpoch is the last justified epoch.
+	LastFinalizedEpoch     uint64            // LastFinalizedEpoch is the last finalized epoch.
+	Dynasty                uint64            // Dynasty is the current dynasty.
+	NextShard              uint16            // NextShard is the next shard that cross-linking assignment will start from.
+	CurrentCheckpoint      common.Hash       // CurrentCheckpoint is the current FFG checkpoint.
+	CrosslinkRecords       []CrosslinkRecord // CrosslinkRecords records about the most recent crosslink for each shard.
+	TotalDeposits          uint              // TotalDeposits is the Total balance of deposits.
+	CrosslinkSeed          common.Hash       // CrosslinkSeed is used to select the committees for each shard.
+	CrosslinkSeedLastReset uint64            // CrosslinkSeedLastReset is the last epoch the crosslink seed was reset.
+}
+
+// ValidatorRecord contains information about a validator
+type ValidatorRecord struct {
+	PubKey           ecdsa.PublicKey // PubKey is the validator's public key.
+	ReturnShard      uint16          // ReturnShard is the shard balance will be sent to after withdrawal.
+	ReturnAddress    common.Address  // ReturnAddress is the address balance will be sent to after withdrawal.
+	RandaoCommitment common.Hash     // RandaoCommitment is validator's current RANDAO beacon commitment.
+	Balance          uint64          // Balance is validator's current balance.
+	SwitchDynasty    uint64          // SwitchDynasty is the dynasty where the validator can (be inducted | be removed | withdraw their balance).
+}
+
+// CrosslinkRecord contains the fields of last fully formed
+// crosslink to be submitted into the chain.
+type CrosslinkRecord struct {
+	Epoch uint64      // Epoch records the epoch the crosslink was submitted in.
+	Hash  common.Hash // Hash is the block hash.
+}