add: Drand network integration with random beacon

config/drand.go

@@ -0,0 +1,30 @@
+package config
+
+type DrandConfig struct {
+	Servers      []string
+	GossipRelays []string
+	ChainInfo    string
+}
+
+func NewDrandConfig() *DrandConfig {
+	cfg := &DrandConfig{
+		Servers: []string{
+			"https://api.drand.sh",
+			"https://api2.drand.sh",
+			"https://api3.drand.sh",
+			"https://drand.cloudflare.com",
+		},
+		GossipRelays: []string{
+			"/dnsaddr/api.drand.sh/",
+			"/dnsaddr/api2.drand.sh/",
+			"/dnsaddr/api3.drand.sh/",
+		},
+		ChainInfo: `{
+			"public_key": "868f005eb8e6e4ca0a47c8a77ceaa5309a47978a7c71bc5cce96366b5d7a569937c529eeda66c7293784a9402801af31",
+			"period": 30,
+			"genesis_time": 1595431050,
+			"hash": "8990e7a9aaed2ffed73dbd7092123d6f289930540d7651336225dc172e51b2ce"
+		}`,
+	}
+	return cfg
+}

go.mod

@@ -7,27 +7,31 @@ require (
 	github.com/aristanetworks/goarista v0.0.0-20200224203130-895b4c57c44d // indirect
 	github.com/cespare/cp v1.1.1 // indirect
 	github.com/deckarep/golang-set v1.7.1 // indirect
+	github.com/drand/drand v1.2.1
+	github.com/drand/kyber v1.1.5
 	github.com/elastic/gosigar v0.10.5 // indirect
 	github.com/ethereum/go-ethereum v1.9.5
+	github.com/filecoin-project/go-state-types v0.0.0-20201021025442-0ac4de847f4f
+	github.com/filecoin-project/lotus v1.1.0
 	github.com/fjl/memsize v0.0.0-20190710130421-bcb5799ab5e5 // indirect
 	github.com/gballet/go-libpcsclite v0.0.0-20191108122812-4678299bea08 // indirect
-	github.com/go-kit/kit v0.10.0 // indirect
+	github.com/go-kit/kit v0.10.0
 	github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e // indirect
 	github.com/golang/protobuf v1.4.2 // indirect
 	github.com/google/uuid v1.1.1
 	github.com/gopherjs/gopherjs v0.0.0-20190812055157-5d271430af9f // indirect
+	github.com/ipfs/go-log v1.0.4
 	github.com/ipfs/go-log/v2 v2.1.2-0.20200626104915-0016c0b4b3e4
 	github.com/karalabe/usb v0.0.0-20191104083709-911d15fe12a9 // indirect
-	github.com/libp2p/go-libp2p v0.10.2
+	github.com/libp2p/go-libp2p v0.11.0
 	github.com/libp2p/go-libp2p-core v0.6.1
 	github.com/libp2p/go-libp2p-discovery v0.5.0
 	github.com/libp2p/go-libp2p-kad-dht v0.8.3
 	github.com/libp2p/go-libp2p-peerstore v0.2.6
-	github.com/libp2p/go-libp2p-pubsub v0.3.3
-	github.com/mattn/go-colorable v0.1.4 // indirect
-	github.com/mattn/go-isatty v0.0.12 // indirect
-	github.com/multiformats/go-multiaddr v0.2.2
+	github.com/libp2p/go-libp2p-pubsub v0.3.6
+	github.com/multiformats/go-multiaddr v0.3.1
 	github.com/olekukonko/tablewriter v0.0.4 // indirect
+	github.com/raulk/clock v1.1.0
 	github.com/rjeczalik/notify v0.9.2 // indirect
 	github.com/rs/cors v1.7.0 // indirect
 	github.com/sirupsen/logrus v1.6.0
@@ -36,18 +40,13 @@ require (
 	github.com/status-im/keycard-go v0.0.0-20200402102358-957c09536969 // indirect
 	github.com/steakknife/bloomfilter v0.0.0-20180922174646-6819c0d2a570 // indirect
 	github.com/steakknife/hamming v0.0.0-20180906055917-c99c65617cd3 // indirect
+	github.com/stretchr/testify v1.6.1
 	github.com/tyler-smith/go-bip39 v1.0.2 // indirect
 	github.com/wsddn/go-ecdh v0.0.0-20161211032359-48726bab9208 // indirect
-	golang.org/x/crypto v0.0.0-20200604202706-70a84ac30bf9 // indirect
 	golang.org/x/lint v0.0.0-20200302205851-738671d3881b // indirect
-	golang.org/x/net v0.0.0-20200602114024-627f9648deb9 // indirect
-	golang.org/x/sys v0.0.0-20200602225109-6fdc65e7d980 // indirect
-	golang.org/x/tools v0.0.0-20200331025713-a30bf2db82d4 // indirect
-	google.golang.org/grpc v1.29.1 // indirect
-	google.golang.org/protobuf v1.24.0 // indirect
+	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1
 	gopkg.in/natefinch/npipe.v2 v2.0.0-20160621034901-c1b8fa8bdcce // indirect
 	gopkg.in/olebedev/go-duktape.v3 v3.0.0-20200619000410-60c24ae608a6 // indirect
 	gopkg.in/urfave/cli.v1 v1.20.0 // indirect
-	gopkg.in/yaml.v2 v2.2.8 // indirect
 	honnef.co/go/tools v0.0.1-2020.1.3 // indirect
 )

lib/clock.go

@@ -0,0 +1,5 @@
+package lib
+
+import "github.com/raulk/clock"
+
+var Clock = clock.New()

lib/drand/drand.go

@@ -0,0 +1,157 @@
+package drand
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/drand/drand/chain"
+	"github.com/drand/drand/client"
+	httpClient "github.com/drand/drand/client/http"
+	libp2pClient "github.com/drand/drand/lp2p/client"
+	"github.com/drand/kyber"
+	"github.com/sirupsen/logrus"
+
+	pubsub "github.com/libp2p/go-libp2p-pubsub"
+
+	"github.com/Secured-Finance/dione/config"
+	"github.com/Secured-Finance/dione/lib"
+)
+
+type DrandRes struct {
+	// PreviousSig is the previous signature generated
+	PreviousSig []byte
+	// Round is the round number this beacon is tied to
+	Round uint64
+	// Signature is the BLS deterministic signature over Round || PreviousRand
+	Signature []byte
+	// Randomness for specific round generated by Drand
+	Randomness []byte
+}
+
+type Beacon struct {
+	DrandResponse DrandRes
+	Error         error
+}
+
+type DrandBeacon struct {
+	DrandClient      client.Client
+	PublicKey        kyber.Point
+	Interval         time.Duration
+	drandGenesisTime uint64
+	cacheLock        sync.Mutex
+	localCache       map[uint64]DrandRes
+}
+
+func NewDrandBeacon(ps *pubsub.PubSub) (*DrandBeacon, error) {
+	cfg := config.NewDrandConfig()
+
+	drandChain, err := chain.InfoFromJSON(bytes.NewReader([]byte(cfg.ChainInfo)))
+	if err != nil {
+		return nil, fmt.Errorf("unable to unmarshal drand chain info: %w", err)
+	}
+
+	var clients []client.Client
+	for _, url := range cfg.Servers {
+		client, err := httpClient.NewWithInfo(url, drandChain, nil)
+		if err != nil {
+			return nil, fmt.Errorf("could not create http drand client: %w", err)
+		}
+		clients = append(clients, client)
+	}
+
+	opts := []client.Option{
+		client.WithChainInfo(drandChain),
+		client.WithCacheSize(1024),
+		client.WithAutoWatch(),
+	}
+
+	if ps != nil {
+		opts = append(opts, libp2pClient.WithPubsub(ps))
+	} else {
+		logrus.Info("Initiated drand with PubSub")
+	}
+
+	drandClient, err := client.Wrap(clients, opts...)
+	if err != nil {
+		return nil, fmt.Errorf("Couldn't create Drand clients")
+	}
+
+	db := &DrandBeacon{
+		DrandClient: drandClient,
+		localCache:  make(map[uint64]DrandRes),
+	}
+
+	db.PublicKey = drandChain.PublicKey
+	db.Interval = drandChain.Period
+	db.drandGenesisTime = uint64(drandChain.GenesisTime)
+
+	return db, nil
+}
+
+func (db *DrandBeacon) Entry(ctx context.Context, round uint64) <-chan Beacon {
+	out := make(chan Beacon, 1)
+	if round != 0 {
+		res := db.getCachedValue(round)
+		if res != nil {
+			out <- Beacon{DrandResponse: *res}
+			close(out)
+			return out
+		}
+	}
+
+	go func() {
+		start := lib.Clock.Now()
+		logrus.Info("start fetching randomness", "round", round)
+		resp, err := db.DrandClient.Get(ctx, round)
+
+		var res Beacon
+		if err != nil {
+			res.Error = fmt.Errorf("drand failed Get request: %w", err)
+		} else {
+			res.DrandResponse.Round = resp.Round()
+			res.DrandResponse.Signature = resp.Signature()
+		}
+		logrus.Info("done fetching randomness", "round", round, "took", lib.Clock.Since(start))
+		out <- res
+		close(out)
+	}()
+
+	return out
+}
+func (db *DrandBeacon) cacheValue(res DrandRes) {
+	db.cacheLock.Lock()
+	defer db.cacheLock.Unlock()
+	db.localCache[res.Round] = res
+}
+
+func (db *DrandBeacon) getCachedValue(round uint64) *DrandRes {
+	db.cacheLock.Lock()
+	defer db.cacheLock.Unlock()
+	v, ok := db.localCache[round]
+	if !ok {
+		return nil
+	}
+	return &v
+}
+
+func (db *DrandBeacon) VerifyEntry(curr DrandRes, prev DrandRes) error {
+	if prev.Round == 0 {
+		return nil
+	}
+	if be := db.getCachedValue(curr.Round); be != nil {
+		return nil
+	}
+	b := &chain.Beacon{
+		PreviousSig: prev.PreviousSig,
+		Round:       curr.Round,
+		Signature:   curr.Signature,
+	}
+	err := chain.VerifyBeacon(db.PublicKey, b)
+	if err == nil {
+		db.cacheValue(curr)
+	}
+	return err
+}

lib/drand/drand_test.go

@@ -0,0 +1,23 @@
+package drand
+
+import (
+	"context"
+	"encoding/hex"
+	"testing"
+
+	"github.com/Secured-Finance/dione/config"
+	drandClient "github.com/drand/drand/client/http"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPrintGroupInfo(t *testing.T) {
+	cfg := config.NewDrandConfig()
+	ctx := context.Background()
+	drandServer := cfg.Servers[0]
+	client, err := drandClient.New(drandServer, nil, nil)
+	assert.NoError(t, err)
+	drandResult, err := client.Get(ctx, 266966)
+	assert.NoError(t, err)
+	stringSha256 := hex.EncodeToString(drandResult.Randomness())
+	assert.Equal(t, stringSha256, "cb67e13477cad0e54540980a3b621dfd9c5fcd7c92ed42626289a1de6f25c3d1")
+}