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Merge 113521c into 5bb9609
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@Gilthoniel
Gilthoniel committed Apr 30, 2020
2 parents 5bb9609 + 113521c commit 8e89690
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Showing 54 changed files with 2,316 additions and 1,691 deletions.
6 changes: 0 additions & 6 deletions blockchain/mod.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,6 @@ import (
"context"

"github.com/golang/protobuf/proto"
"go.dedis.ch/fabric/crypto"
"go.dedis.ch/fabric/encoding"
mino "go.dedis.ch/fabric/mino"
)
Expand All @@ -19,9 +18,6 @@ type Block interface {
// GetHash returns the footprint of the block.
GetHash() []byte

// GetPlayers returns the participants involved in the block creation.
GetPlayers() mino.Players

// GetPayload returns the payload of the block.
GetPayload() proto.Message
}
Expand All @@ -30,8 +26,6 @@ type Block interface {
// verified from the genesis block.
type VerifiableBlock interface {
Block

Verify(crypto.Verifier) error
}

// BlockFactory provides primitives to create blocks from a untrusted source.
Expand Down
184 changes: 36 additions & 148 deletions blockchain/skipchain/block.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2,17 +2,14 @@ package skipchain

import (
"bytes"
"crypto/sha256"
"encoding/binary"
fmt "fmt"
"hash"

proto "github.com/golang/protobuf/proto"
"go.dedis.ch/fabric/blockchain"
"go.dedis.ch/fabric/consensus"
"go.dedis.ch/fabric/crypto"
"go.dedis.ch/fabric/encoding"
"go.dedis.ch/fabric/mino"
"golang.org/x/xerrors"
)

Expand All @@ -29,33 +26,18 @@ func (d Digest) String() string {
return fmt.Sprintf("%x", d[:])[:16]
}

// sha256Factory is a factory for SHA256 digests.
//
// - implements crypto.HashFactory
type sha256Factory struct{}

// New implements crypto.HashFactory. It returns a new instance of a SHA256
// hash.
func (f sha256Factory) New() hash.Hash {
return sha256.New()
}

// SkipBlock is a representation of the data held by a block. It contains the
// information to build a skipchain.
//
// - implements blockchain.Block
// - implements consensus.Proposal
// - implements fmt.Stringer
type SkipBlock struct {
hash Digest
verifier crypto.Verifier
hash Digest

// Index is the block index since the genesis block.
Index uint64

// Conodes is the list of conodes participating in the consensus.
Conodes Conodes

// GenesisID is the hash of the genesis block which represents the chain
// identifier.
GenesisID Digest
Expand All @@ -68,35 +50,6 @@ type SkipBlock struct {
Payload proto.Message
}

func newSkipBlock(
encoder encoding.ProtoMarshaler,
hashFactory crypto.HashFactory,
verifier crypto.Verifier,
index uint64,
conodes Conodes,
id Digest,
backLink Digest,
data proto.Message,
) (SkipBlock, error) {
block := SkipBlock{
verifier: verifier,
Index: index,
Conodes: conodes,
GenesisID: id,
BackLink: backLink,
Payload: data,
}

hash, err := block.computeHash(hashFactory, encoder)
if err != nil {
return SkipBlock{}, xerrors.Errorf("couldn't hash the block: %w", err)
}

block.hash = hash

return block, nil
}

// GetIndex returns the index of the block since the genesis block.
func (b SkipBlock) GetIndex() uint64 {
return b.Index
Expand All @@ -114,18 +67,6 @@ func (b SkipBlock) GetPreviousHash() []byte {
return b.BackLink.Bytes()
}

// GetPlayers implements blockchain.Block. It returns the list of players.
func (b SkipBlock) GetPlayers() mino.Players {
return b.Conodes
}

// GetVerifier implements consensus.Proposal. It returns the verifier for the
// block.
// TODO: it might have sense to remove this function.
func (b SkipBlock) GetVerifier() crypto.Verifier {
return b.verifier
}

// GetPayload implements blockchain.Block. It returns the block payload.
func (b SkipBlock) GetPayload() proto.Message {
return b.Payload
Expand All @@ -139,17 +80,11 @@ func (b SkipBlock) Pack(encoder encoding.ProtoMarshaler) (proto.Message, error)
return nil, xerrors.Errorf("couldn't marshal the payload: %v", err)
}

roster, err := encoder.Pack(b.Conodes)
if err != nil {
return nil, xerrors.Errorf("couldn't pack the conodes: %v", err)
}

blockproto := &BlockProto{
Index: b.Index,
GenesisID: b.GenesisID.Bytes(),
Backlink: b.BackLink.Bytes(),
Payload: payloadAny,
Roster: roster.(*Roster),
}

return blockproto, nil
Expand All @@ -173,13 +108,6 @@ func (b SkipBlock) computeHash(factory crypto.HashFactory,
return Digest{}, xerrors.Errorf("couldn't write index: %v", err)
}

if b.Conodes != nil {
_, err = b.Conodes.WriteTo(h)
if err != nil {
return Digest{}, xerrors.Errorf("couldn't write conodes: %v", err)
}
}

_, err = h.Write(b.GenesisID.Bytes())
if err != nil {
return Digest{}, xerrors.Errorf("couldn't write genesis hash: %v", err)
Expand Down Expand Up @@ -211,21 +139,6 @@ type VerifiableBlock struct {
Chain consensus.Chain
}

// Verify implements blockchain.VerifiableBlock. It makes sure the integrity of
// the chain is valid.
func (vb VerifiableBlock) Verify(v crypto.Verifier) error {
err := vb.Chain.Verify(v)
if err != nil {
return xerrors.Errorf("couldn't verify the chain: %v", err)
}

if !bytes.Equal(vb.GetHash(), vb.Chain.GetLastHash()) {
return xerrors.Errorf("mismatch target %x != %x", vb.GetHash(), vb.Chain.GetLastHash())
}

return nil
}

// Pack implements encoding.Packable. It returns the protobuf message for a
// verifiable block.
func (vb VerifiableBlock) Pack(enc encoding.ProtoMarshaler) (proto.Message, error) {
Expand All @@ -251,9 +164,20 @@ func (vb VerifiableBlock) Pack(enc encoding.ProtoMarshaler) (proto.Message, erro
//
// - implements blockchain.BlockFactory
type blockFactory struct {
*Skipchain
encoder encoding.ProtoMarshaler
hashFactory crypto.HashFactory
consensus consensus.Consensus
}

func (f blockFactory) prepareBlock(block *SkipBlock) error {
hash, err := block.computeHash(f.hashFactory, f.encoder)
if err != nil {
return xerrors.Errorf("couldn't hash the block: %w", err)
}

block.hash = hash

return nil
}

func (f blockFactory) fromPrevious(prev SkipBlock, data proto.Message) (SkipBlock, error) {
Expand All @@ -264,43 +188,21 @@ func (f blockFactory) fromPrevious(prev SkipBlock, data proto.Message) (SkipBloc
genesisID = prev.GenesisID
}

block, err := newSkipBlock(
f.encoder,
f.hashFactory,
prev.verifier,
prev.Index+1,
prev.Conodes,
genesisID,
prev.hash,
data,
)
block := SkipBlock{
Index: prev.Index + 1,
GenesisID: genesisID,
BackLink: prev.hash,
Payload: data,
}

err := f.prepareBlock(&block)
if err != nil {
return block, xerrors.Errorf("couldn't make block: %w", err)
}

return block, nil
}

func (f blockFactory) decodeConodes(msgs []*ConodeProto) (Conodes, error) {
pubkeyFactory := f.cosi.GetPublicKeyFactory()
addrFactory := f.mino.GetAddressFactory()

conodes := make(Conodes, len(msgs))
for i, msg := range msgs {
publicKey, err := pubkeyFactory.FromProto(msg.GetPublicKey())
if err != nil {
return nil, xerrors.Errorf("couldn't decode public key: %v", err)
}

conodes[i] = Conode{
addr: addrFactory.FromText(msg.GetAddress()),
publicKey: publicKey,
}
}
return conodes, nil
}

func (f blockFactory) decodeBlock(src proto.Message) (SkipBlock, error) {
in, ok := src.(*BlockProto)
if !ok {
Expand All @@ -315,32 +217,19 @@ func (f blockFactory) decodeBlock(src proto.Message) (SkipBlock, error) {
backLink := Digest{}
copy(backLink[:], in.GetBacklink())

conodes, err := f.decodeConodes(in.GetRoster().GetConodes())
if err != nil {
return SkipBlock{}, err
}

verifier, err := f.cosi.GetVerifier(conodes)
if err != nil {
return SkipBlock{}, xerrors.Errorf("couldn't make verifier: %v", err)
}

genesisID := Digest{}
copy(genesisID[:], in.GetGenesisID())

block, err := newSkipBlock(
f.encoder,
f.hashFactory,
verifier,
in.GetIndex(),
conodes,
genesisID,
backLink,
payload,
)
block := SkipBlock{
Index: in.GetIndex(),
GenesisID: genesisID,
BackLink: backLink,
Payload: payload,
}

err = f.prepareBlock(&block)
if err != nil {
return block, xerrors.Errorf("couldn't make block: %v", err)
return block, xerrors.Errorf("couldn't prepare block: %v", err)
}

return block, nil
Expand All @@ -359,21 +248,20 @@ func (f blockFactory) FromVerifiable(src proto.Message) (blockchain.Block, error
return nil, xerrors.Errorf("couldn't decode the block: %v", err)
}

chainFactory := f.consensus.GetChainFactory()
chainFactory, err := f.consensus.GetChainFactory()
if err != nil {
return nil, xerrors.Errorf("couldn't get the chain factory: %v", err)
}

// Integrity of the chain is verified during decoding.
chain, err := chainFactory.FromProto(in.GetChain())
if err != nil {
return nil, xerrors.Errorf("couldn't decode the chain: %v", err)
}

vb := VerifiableBlock{
SkipBlock: block,
Chain: chain,
}

err = vb.Verify(block.verifier)
if err != nil {
return nil, xerrors.Errorf("couldn't verify: %v", err)
// Only the link between the chain and the block needs to be verified.
if !bytes.Equal(chain.GetLastHash(), block.hash[:]) {
return nil, xerrors.Errorf("mismatch hashes: %#x != %#x", chain.GetLastHash(), block.hash)
}

return block, nil
Expand Down
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