Add transactions multi-signing. (#76)

* Add transaction multi-signing.
* Add `MultiSign` and `SetSigners` methods for transactions to be signed from multi-signing.
* Add additional `MultiSignable` interface for the `BaseTx` and implement it.
*  Fix structure used by `SIGNER_LIST_SET`  and `multi-signing`
*  Add missing `temBAD_WEIGHT` error code

.gitignore

@@ -27,3 +27,7 @@ _testmain.go
 *.coverprofile
 
 .DS_Store
+
+# IDE specific
+.idea
+*.iml

data/encoder.go

@@ -11,16 +11,20 @@ import (
 )
 
 func Raw(h Hashable) (Hash256, []byte, error) {
-	return raw(h, h.Prefix(), false)
+	return raw(h, h.Prefix(), nil, false)
 }
 
 func NodeId(h Hashable) (Hash256, error) {
-	nodeid, _, err := raw(h, h.Prefix(), false)
+	nodeid, _, err := raw(h, h.Prefix(), nil, false)
 	return nodeid, err
 }
 
 func SigningHash(s Signable) (Hash256, []byte, error) {
-	return raw(s, s.SigningPrefix(), true)
+	return raw(s, s.SigningPrefix(), nil, true)
+}
+
+func MultiSigningHash(s MultiSignable, account Account) (Hash256, []byte, error) {
+	return raw(s, s.MultiSigningPrefix(), account.Bytes(), true)
 }
 
 func Node(h Storer) (Hash256, []byte, error) {
@@ -30,14 +34,14 @@ func Node(h Storer) (Hash256, []byte, error) {
 			return zero256, nil, err
 		}
 	}
-	key, value, err := raw(h, h.Prefix(), true)
+	key, value, err := raw(h, h.Prefix(), nil, true)
 	if err != nil {
 		return zero256, nil, err
 	}
 	return key, append(header.Bytes(), value...), nil
 }
 
-func raw(value interface{}, prefix HashPrefix, ignoreSigningFields bool) (Hash256, []byte, error) {
+func raw(value interface{}, prefix HashPrefix, suffix []byte, ignoreSigningFields bool) (Hash256, []byte, error) {
 	buf := new(bytes.Buffer)
 	hasher := sha512.New()
 	multi := io.MultiWriter(buf, hasher)
@@ -47,6 +51,9 @@ func raw(value interface{}, prefix HashPrefix, ignoreSigningFields bool) (Hash25
 	if err := writeRaw(multi, value, ignoreSigningFields); err != nil {
 		return zero256, nil, err
 	}
+	if err := write(hasher, suffix); err != nil {
+		return zero256, nil, err
+	}
 	var hash Hash256
 	copy(hash[:], hasher.Sum(nil))
 	return hash, buf.Bytes(), nil

data/format.go

@@ -14,14 +14,15 @@ type LedgerNamespace uint16
 
 const (
 	// Hash Prefixes
-	HP_TRANSACTION_ID   HashPrefix = 0x54584E00 // 'TXN' transaction
-	HP_TRANSACTION_NODE HashPrefix = 0x534E4400 // 'SND' transaction plus metadata (probably should have been TND!)
-	HP_LEAF_NODE        HashPrefix = 0x4D4C4E00 // 'MLN' account state
-	HP_INNER_NODE       HashPrefix = 0x4D494E00 // 'MIN' inner node in tree
-	HP_LEDGER_MASTER    HashPrefix = 0x4C575200 // 'LWR' ledger master data for signing (probably should have been LGR!)
-	HP_TRANSACTION_SIGN HashPrefix = 0x53545800 // 'STX' inner transaction to sign
-	HP_VALIDATION       HashPrefix = 0x56414C00 // 'VAL' validation for signing
-	HP_PROPOSAL         HashPrefix = 0x50525000 // 'PRP' proposal for signing
+	HP_TRANSACTION_ID        HashPrefix = 0x54584E00 // 'TXN' transaction
+	HP_TRANSACTION_NODE      HashPrefix = 0x534E4400 // 'SND' transaction plus metadata (probably should have been TND!)
+	HP_LEAF_NODE             HashPrefix = 0x4D4C4E00 // 'MLN' account state
+	HP_INNER_NODE            HashPrefix = 0x4D494E00 // 'MIN' inner node in tree
+	HP_LEDGER_MASTER         HashPrefix = 0x4C575200 // 'LWR' ledger master data for signing (probably should have been LGR!)
+	HP_TRANSACTION_SIGN      HashPrefix = 0x53545800 // 'STX' inner transaction to sign
+	HP_TRANSACTION_MULTISIGN HashPrefix = 0x534D5400 // 'SMT' inner transaction to multi-sign
+	HP_VALIDATION            HashPrefix = 0x56414C00 // 'VAL' validation for signing
+	HP_PROPOSAL              HashPrefix = 0x50525000 // 'PRP' proposal for signing
 
 	// Node Types
 	NT_UNKNOWN          NodeType = 0

data/interface.go

@@ -18,6 +18,15 @@ type Signable interface {
 	GetSignature() *VariableLength
 }
 
+type MultiSignable interface {
+	Hashable
+	InitialiseForSigning()
+	MultiSigningPrefix() HashPrefix
+	GetPublicKey() *PublicKey
+	GetSignature() *VariableLength
+	SetSigners([]Signer)
+}
+
 type Router interface {
 	Hashable
 	SuppressionId() Hash256

data/ledgerentry.go

@@ -133,12 +133,16 @@ type Escrow struct {
 	DestinationNode *NodeIndex       `json:",omitempty"`
 }
 
-type SignerEntry struct {
+type SignerEntryItem struct {
 	Account       *Account `json:",omitempty"`
 	SignerWeight  *uint16  `json:",omitempty"`
 	WalletLocator *Hash256 `json:",omitempty"`
 }
 
+type SignerEntry struct {
+	SignerEntry SignerEntryItem
+}
+
 type SignerList struct {
 	leBase
 	Flags         *LedgerEntryFlag `json:",omitempty"`
@@ -233,7 +237,7 @@ func (s *Escrow) Affects(account Account) bool {
 }
 func (s *SignerList) Affects(account Account) bool {
 	for _, entry := range s.SignerEntries {
-		if entry.Account != nil && entry.Account.Equals(account) {
+		if entry.SignerEntry.Account != nil && entry.SignerEntry.Account.Equals(account) {
 			return true
 		}
 	}

data/result.go

@@ -323,6 +323,7 @@ var resultNames = map[TransactionResult]struct {
 	temCANNOT_PREAUTH_SELF:      {"temCANNOT_PREAUTH_SELF", "Malformed: An account may not preauthorize itself."},
 	temSEQ_AND_TICKET:           {"temSEQ_AND_TICKET", "Transaction contains a TicketSequence and a non-zero Sequence"},
 	temBAD_NFTOKEN_TRANSFER_FEE: {"temBAD_NFTOKEN_TRANSFER_FEE", "Malformed: The NFToken transfer fee must be between 1 and 5000, inclusive."},
+	temBAD_WEIGHT:               {"temBAD_WEIGHT", "The SignerListSet transaction includes a SignerWeight that is invalid, for example a zero or negative value."},
 
 	terRETRY:       {"terRETRY", "Retry transaction."},
 	terFUNDS_SPENT: {"terFUNDS_SPENT", "Can't set password, password set funds already spent."},

data/signing.go

@@ -13,7 +13,7 @@ func Sign(s Signable, key crypto.Key, sequence *uint32) error {
 	if err != nil {
 		return err
 	}
-	*s.GetSignature() = VariableLength(sig)
+	*s.GetSignature() = sig
 	hash, _, err = Raw(s)
 	if err != nil {
 		return err
@@ -29,3 +29,35 @@ func CheckSignature(s Signable) (bool, error) {
 	}
 	return crypto.Verify(s.GetPublicKey().Bytes(), hash.Bytes(), msg, s.GetSignature().Bytes())
 }
+
+func MultiSign(s MultiSignable, key crypto.Key, sequence *uint32, account Account) error {
+	s.InitialiseForSigning()
+	hash, msg, err := MultiSigningHash(s, account)
+	if err != nil {
+		return err
+	}
+	//
+	msg = append(s.MultiSigningPrefix().Bytes(), msg...)
+	msg = append(msg, account.Bytes()...)
+
+	sig, err := crypto.Sign(key.Private(sequence), hash.Bytes(), msg)
+	if err != nil {
+		return err
+	}
+	*s.GetSignature() = sig
+	// copy pub key only after the signing
+	copy(s.GetPublicKey().Bytes(), key.Public(sequence))
+
+	return nil
+}
+
+func SetSigners(s MultiSignable, signers ...Signer) error {
+	s.SetSigners(signers)
+
+	hash, _, err := Raw(s)
+	if err != nil {
+		return err
+	}
+	copy(s.GetHash().Bytes(), hash.Bytes())
+	return nil
+}

data/transaction.go

@@ -17,10 +17,14 @@ type TxBase struct {
 	Hash               Hash256         `json:"hash"`
 }
 
-type Signer struct {
+type SignerItem struct {
 	Account       Account
-	TxnSignature  *VariableLength
-	SigningPubKey *PublicKey
+	TxnSignature  *VariableLength `json:",omitempty"`
+	SigningPubKey *PublicKey      `json:",omitempty"`
+}
+
+type Signer struct {
+	Signer SignerItem
 }
 
 type Payment struct {
@@ -258,6 +262,8 @@ func (t *TxBase) Prefix() HashPrefix                  { return HP_TRANSACTION_ID
 func (t *TxBase) GetPublicKey() *PublicKey            { return t.SigningPubKey }
 func (t *TxBase) GetSignature() *VariableLength       { return t.TxnSignature }
 func (t *TxBase) SigningPrefix() HashPrefix           { return HP_TRANSACTION_SIGN }
+func (t *TxBase) MultiSigningPrefix() HashPrefix      { return HP_TRANSACTION_MULTISIGN }
+func (t *TxBase) SetSigners(signers []Signer)         { t.Signers = signers }
 func (t *TxBase) PathSet() PathSet                    { return PathSet(nil) }
 func (t *TxBase) GetHash() *Hash256                   { return &t.Hash }
 

go.sum

@@ -2,10 +2,10 @@ github.com/bits-and-blooms/bitset v1.2.1 h1:M+/hrU9xlMp7t4TyTDQW97d3tRPVuKFC6zBE
 github.com/bits-and-blooms/bitset v1.2.1/go.mod h1:gIdJ4wp64HaoK2YrL1Q5/N7Y16edYb8uY+O0FJTyyDA=
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-github.com/btcsuite/btcd/chaincfg/chainhash v1.0.0/go.mod h1:7SFka0XMvUgj3hfZtydOrQY2mwhPclbT2snogU7SQQc=
+github.com/btcsuite/btcd/chaincfg/chainhash v1.0.0 h1:MSskdM4/xJYcFzy0altH/C/xHopifpWzHUi1JeVI34Q=
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 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
-github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/decred/dcrd/crypto/blake256 v1.0.0 h1:/8DMNYp9SGi5f0w7uCm6d6M4OU2rGFK09Y2A4Xv7EE0=
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@@ -71,21 +71,17 @@ golang.org/x/net v0.0.0-20180406214816-61147c48b25b/go.mod h1:mL1N/T3taQHkDXs73r
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-golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
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