core: move transaction's sender to cosigners

Closes #1184 Ported changes from https://github.com/neo-project/neo/pull/1752
2020-07-29 19:57:38 +03:00 · 2020-07-29 19:57:38 +03:00 · 90825efa16
commit 90825efa16
parent 8697582b23
36 changed files with 307 additions and 264 deletions
--- a/cli/smartcontract/smart_contract.go
+++ b/cli/smartcontract/smart_contract.go
@ -148,11 +148,13 @@ func NewCommands() []cli.Command {
 			{
 				Name:      "invokefunction",
 				Usage:     "invoke deployed contract on the blockchain",
-				UsageText: "neo-go contract invokefunction -r endpoint -w wallet [-a address] [-g gas] scripthash [method] [arguments...] [--] [cosigners...]",
+				UsageText: "neo-go contract invokefunction -r endpoint -w wallet [-a address] [-g gas] scripthash [method] [arguments...] [--] [signers...]",
 				Description: `Executes given (as a script hash) deployed script with the given method,
-   arguments and cosigners. See testinvokefunction documentation for the details
-   about parameters. It differs from testinvokefunction in that this command
-   sends an invocation transaction to the network.
+   arguments and signers. Sender is included in the list of signers by default
+   with FeeOnly witness scope. If you'd like to change default sender's scope, 
+   specify it via signers parameter. See testinvokefunction documentation for 
+   the details about parameters. It differs from testinvokefunction in that this
+   command sends an invocation transaction to the network.
 `,
 				Action: invokeFunction,
 				Flags:  invokeFunctionFlags,
@ -160,14 +162,15 @@ func NewCommands() []cli.Command {
 			{
 				Name:      "testinvokefunction",
 				Usage:     "invoke deployed contract on the blockchain (test mode)",
-				UsageText: "neo-go contract testinvokefunction -r endpoint scripthash [method] [arguments...] [--] [cosigners...]",
+				UsageText: "neo-go contract testinvokefunction -r endpoint scripthash [method] [arguments...] [--] [signers...]",
 				Description: `Executes given (as a script hash) deployed script with the given method,
-   arguments and cosigners. If no method is given "" is passed to the script, if
-   no arguments are given, an empty array is passed, if no cosigners are given,
-   no array will be passed. All of the given arguments are encapsulated into 
-   array before invoking the script. The script thus should follow the regular
-   convention of smart contract arguments (method string and an array of other 
-   arguments).
+   arguments and signers (sender is not included by default). If no method is given
+   "" is passed to the script, if no arguments are given, an empty array is 
+   passed, if no signers are given no array is passed. If signers are specified,
+   the first one of them is treated as a sender. All of the given arguments are 
+   encapsulated into array before invoking the script. The script thus should 
+   follow the regular convention of smart contract arguments (method string and 
+   an array of other arguments).

   Arguments always do have regular Neo smart contract parameter types, either
   specified explicitly or being inferred from the value. To specify the type
@ -224,12 +227,15 @@ func NewCommands() []cli.Command {
    * '03b209fd4f53a7170ea4444e0cb0a6bb6a53c2bd016926989cf85f9b0fba17a70c' is a
      key with a value of '03b209fd4f53a7170ea4444e0cb0a6bb6a53c2bd016926989cf85f9b0fba17a70c'

-   Cosigners represent a set of Uint160 hashes with witness scopes and are used
-   to verify hashes in System.Runtime.CheckWitness syscall. To specify cosigners
-   use cosigner[:scope] syntax where
-    * 'cosigner' is hex-encoded 160 bit (20 byte) LE value of cosigner's address,
+   Signers represent a set of Uint160 hashes with witness scopes and are used
+   to verify hashes in System.Runtime.CheckWitness syscall. First signer is treated
+   as a sender. To specify signers use signer[:scope] syntax where
+    * 'signer' is hex-encoded 160 bit (20 byte) LE value of signer's address,
                 which could have '0x' prefix.
    * 'scope' is a comma-separated set of cosigner's scopes, which could be:
+        - 'FeeOnly' - marks transaction's sender and can be used only for the
+                      sender. Signer with this scope can't be used during the
+                      script execution and only pays fees for the transaction.
        - 'Global' - allows this witness in all contexts. This cannot be combined
                     with other flags.
        - 'CalledByEntry' - means that this condition must hold: EntryScriptHash 
@ -240,8 +246,8 @@ func NewCommands() []cli.Command {
        - 'CustomContracts' - define valid custom contract hashes for witness check.
        - 'CustomGroups' - define custom pubkey for group members.

-   If no scopes were specified, 'Global' used as default. If no cosigners were
-   specified, no array will be passed. Note that scopes are properly handled by 
+   If no scopes were specified, 'Global' used as default. If no signers were
+   specified, no array is passed. Note that scopes are properly handled by 
   neo-go RPC server only. C# implementation does not support scopes capability.

   Examples:
@ -256,9 +262,10 @@ func NewCommands() []cli.Command {
 			{
 				Name:      "testinvokescript",
 				Usage:     "Invoke compiled AVM code in NEF format on the blockchain (test mode, not creating a transaction for it)",
-				UsageText: "neo-go contract testinvokescript -r endpoint -i input.nef [cosigners...]",
+				UsageText: "neo-go contract testinvokescript -r endpoint -i input.nef [signers...]",
 				Description: `Executes given compiled AVM instructions in NEF format with the given set of
-   cosigners. See testinvokefunction documentation for the details about parameters.
+   signers not included sender by default. See testinvokefunction documentation 
+   for the details about parameters.
 `,
 				Action: testInvokeScript,
 				Flags:  testInvokeScriptFlags,
@ -389,7 +396,7 @@ func invokeInternal(ctx *cli.Context, signAndPush bool) error {
 		operation      string
 		params         = make([]smartcontract.Parameter, 0)
 		paramsStart    = 1
-		cosigners      []transaction.Cosigner
+		cosigners      []transaction.Signer
 		cosignersStart = 0
 		resp           *result.Invoke
 		acc            *wallet.Account
@ -493,14 +500,14 @@ func testInvokeScript(ctx *cli.Context) error {
 	}

 	args := ctx.Args()
-	var cosigners []transaction.Cosigner
+	var signers []transaction.Signer
 	if args.Present() {
 		for i, c := range args[:] {
 			cosigner, err := parseCosigner(c)
 			if err != nil {
-				return cli.NewExitError(fmt.Errorf("failed to parse cosigner #%d: %v", i+1, err), 1)
+				return cli.NewExitError(fmt.Errorf("failed to parse signer #%d: %v", i+1, err), 1)
 			}
-			cosigners = append(cosigners, cosigner)
+			signers = append(signers, cosigner)
 		}
 	}

@ -512,7 +519,7 @@ func testInvokeScript(ctx *cli.Context) error {
 		return err
 	}

-	resp, err := c.InvokeScript(nefFile.Script, cosigners)
+	resp, err := c.InvokeScript(nefFile.Script, signers)
 	if err != nil {
 		return cli.NewExitError(err, 1)
 	}
@ -659,7 +666,7 @@ func contractDeploy(ctx *cli.Context) error {
 	if err != nil {
 		return cli.NewExitError(fmt.Errorf("failed to create deployment script: %v", err), 1)
 	}
-	// It doesn't require any cosigners.
+	// It doesn't require any signers.
 	invRes, err := c.InvokeScript(txScript, nil)
 	if err != nil {
 		return cli.NewExitError(fmt.Errorf("failed to test-invoke deployment script: %v", err), 1)
@ -687,10 +694,10 @@ func parseContractConfig(confFile string) (ProjectConfig, error) {
 	return conf, nil
 }

-func parseCosigner(c string) (transaction.Cosigner, error) {
+func parseCosigner(c string) (transaction.Signer, error) {
 	var (
 		err error
-		res = transaction.Cosigner{
+		res = transaction.Signer{
 			Scopes: transaction.Global,
 		}
 	)
@ -706,7 +713,7 @@ func parseCosigner(c string) (transaction.Cosigner, error) {
 	if len(data) > 1 {
 		res.Scopes, err = transaction.ScopesFromString(data[1])
 		if err != nil {
-			return transaction.Cosigner{}, err
+			return transaction.Signer{}, err
 		}
 	}
 	return res, nil
--- a/docs/notifications.md
+++ b/docs/notifications.md
@ -13,7 +13,7 @@ Currently supported events:
   Filters: primary ID.
 * new transaction in the block
   Contents: transaction.
-   Filters: sender and cosigner.
+   Filters: sender and signer.
 * notification generated during execution
   Contents: container hash, contract script hash, stack item.
   Filters: contract script hash.
@ -57,8 +57,8 @@ Recognized stream names:
   ConsensusData.
 * `transaction_added`
   Filter: `sender` field containing string with hex-encoded Uint160 (LE
-   representation) for transaction's `Sender` and/or `cosigner` in the same
-   format for one of transaction's `Cosigners`.
+   representation) for transaction's `Sender` and/or `signer` in the same
+   format for one of transaction's `Signers`.
 * `notification_from_execution`
   Filter: `contract` field containing string with hex-encoded Uint160 (LE
   representation).
@ -203,7 +203,7 @@ Example:
               "sysfee" : "0",
               "type" : "InvocationTransaction",
               "nonce" : 9,
-               "cosigners" : [
+               "signers" : [
                  {
                     "scopes" : 1,
                     "account" : "0x870958fd19ee3f6c7dc3c2df399d013910856e31"
@ -262,7 +262,7 @@ Example:
         "nonce" : 9,
         "vin" : [],
         "type" : "InvocationTransaction",
-         "cosigners" : [
+         "signers" : [
            {
               "account" : "0x870958fd19ee3f6c7dc3c2df399d013910856e31",
               "scopes" : 1
--- a/integration/performance_test.go
+++ b/integration/performance_test.go
@ -80,7 +80,12 @@ func getTX(t *testing.B, wif *keys.WIF) *transaction.Transaction {

 	tx := transaction.New(netmode.UnitTestNet, []byte{0x51}, 1)
 	tx.Version = 0
-	tx.Sender = fromAddressHash
+	tx.Signers = []transaction.Signer{
+		{
+			Account: fromAddressHash,
+			Scopes:  transaction.FeeOnly,
+		},
+	}
 	tx.Attributes = append(tx.Attributes,
 		transaction.Attribute{
 			Usage: transaction.DescriptionURL,
--- a/pkg/consensus/consensus_test.go
+++ b/pkg/consensus/consensus_test.go
@ -246,7 +246,11 @@ var neoOwner = testchain.MultisigScriptHash()

 func addSender(t *testing.T, txs ...*transaction.Transaction) {
 	for _, tx := range txs {
-		tx.Sender = neoOwner
+		tx.Signers = []transaction.Signer{
+			{
+				Account: neoOwner,
+			},
+		}
 	}
 }

--- a/pkg/core/blockchain.go
+++ b/pkg/core/blockchain.go
@ -1226,7 +1226,7 @@ func (bc *Blockchain) verifyTx(t *transaction.Transaction, block *block.Block) e
 	if maxBlockSystemFee < t.SystemFee {
 		return errors.Errorf("policy check failed: transaction's fee shouldn't exceed maximum block system fee %d", maxBlockSystemFee)
 	}
-	balance := bc.GetUtilityTokenBalance(t.Sender)
+	balance := bc.GetUtilityTokenBalance(t.Sender())
 	need := t.SystemFee + t.NetworkFee
 	if balance.Cmp(big.NewInt(need)) < 0 {
 		return errors.Errorf("insufficient funds: balance is %v, need: %v", balance, need)
@ -1415,15 +1415,9 @@ func (bc *Blockchain) GetEnrollments() ([]state.Validator, error) {
 // to verify whether the transaction is bonafide or not.
 // Golang implementation of GetScriptHashesForVerifying method in C# (https://github.com/neo-project/neo/blob/master/neo/Network/P2P/Payloads/Transaction.cs#L190)
 func (bc *Blockchain) GetScriptHashesForVerifying(t *transaction.Transaction) ([]util.Uint160, error) {
-	hashes := make(map[util.Uint160]bool)
-	hashes[t.Sender] = true
-	for _, c := range t.Cosigners {
-		hashes[c.Account] = true
-	}
-	// convert hashes to []util.Uint160
-	hashesResult := make([]util.Uint160, 0, len(hashes))
-	for h := range hashes {
-		hashesResult = append(hashesResult, h)
+	hashesResult := make([]util.Uint160, len(t.Signers))
+	for i, s := range t.Signers {
+		hashesResult[i] = s.Account
 	}

 	return hashesResult, nil
--- a/pkg/core/blockchain_test.go
+++ b/pkg/core/blockchain_test.go
@ -107,7 +107,7 @@ func TestGetHeader(t *testing.T) {
 	bc := newTestChain(t)
 	tx := transaction.New(netmode.UnitTestNet, []byte{byte(opcode.PUSH1)}, 0)
 	tx.ValidUntilBlock = bc.BlockHeight() + 1
-	assert.Nil(t, addSender(tx))
+	addSigners(tx)
 	assert.Nil(t, signTx(bc, tx))
 	block := bc.newBlock(tx)
 	err := bc.AddBlock(block)
@ -276,7 +276,7 @@ func TestSubscriptions(t *testing.T) {
 	emit.Syscall(script.BinWriter, "System.Runtime.Notify")
 	require.NoError(t, script.Err)
 	txGood1 := transaction.New(netmode.UnitTestNet, script.Bytes(), 0)
-	txGood1.Sender = neoOwner
+	txGood1.Signers = []transaction.Signer{{Account: neoOwner}}
 	txGood1.Nonce = 1
 	txGood1.ValidUntilBlock = 100500
 	require.NoError(t, signTx(bc, txGood1))
@ -288,7 +288,7 @@ func TestSubscriptions(t *testing.T) {
 	emit.Opcode(script.BinWriter, opcode.THROW)
 	require.NoError(t, script.Err)
 	txBad := transaction.New(netmode.UnitTestNet, script.Bytes(), 0)
-	txBad.Sender = neoOwner
+	txBad.Signers = []transaction.Signer{{Account: neoOwner}}
 	txBad.Nonce = 2
 	txBad.ValidUntilBlock = 100500
 	require.NoError(t, signTx(bc, txBad))
@ -298,7 +298,7 @@ func TestSubscriptions(t *testing.T) {
 	emit.Syscall(script.BinWriter, "System.Runtime.Notify")
 	require.NoError(t, script.Err)
 	txGood2 := transaction.New(netmode.UnitTestNet, script.Bytes(), 0)
-	txGood2.Sender = neoOwner
+	txGood2.Signers = []transaction.Signer{{Account: neoOwner}}
 	txGood2.Nonce = 3
 	txGood2.ValidUntilBlock = 100500
 	require.NoError(t, signTx(bc, txGood2))
--- a/pkg/core/helper_test.go
+++ b/pkg/core/helper_test.go
@ -190,8 +190,7 @@ func TestCreateBasicChain(t *testing.T) {
 	txMoveNeo := newNEP5Transfer(neoHash, neoOwner, priv0ScriptHash, neoAmount)
 	txMoveNeo.ValidUntilBlock = validUntilBlock
 	txMoveNeo.Nonce = getNextNonce()
-	txMoveNeo.Sender = neoOwner
-	txMoveNeo.Cosigners = []transaction.Cosigner{{
+	txMoveNeo.Signers = []transaction.Signer{{
 		Account:          neoOwner,
 		Scopes:           transaction.CalledByEntry,
 		AllowedContracts: nil,
@ -202,8 +201,7 @@ func TestCreateBasicChain(t *testing.T) {
 	txMoveGas := newNEP5Transfer(gasHash, neoOwner, priv0ScriptHash, int64(util.Fixed8FromInt64(1000)))
 	txMoveGas.ValidUntilBlock = validUntilBlock
 	txMoveGas.Nonce = getNextNonce()
-	txMoveGas.Sender = neoOwner
-	txMoveGas.Cosigners = []transaction.Cosigner{{
+	txMoveGas.Signers = []transaction.Signer{{
 		Account:          neoOwner,
 		Scopes:           transaction.CalledByEntry,
 		AllowedContracts: nil,
@ -212,8 +210,14 @@ func TestCreateBasicChain(t *testing.T) {
 	require.NoError(t, signTx(bc, txMoveGas))
 	b := bc.newBlock(txMoveNeo, txMoveGas)
 	require.NoError(t, bc.AddBlock(b))
-	t.Logf("txMoveNeo: %s", txMoveNeo.Hash().StringLE())
-	t.Logf("txMoveGas: %s", txMoveGas.Hash().StringLE())
+	t.Logf("Block1 hash: %s", b.Hash().StringLE())
+	bw := io.NewBufBinWriter()
+	b.EncodeBinary(bw.BinWriter)
+	require.NoError(t, bw.Err)
+	t.Logf("Block1 hex: %s", bw.Bytes())
+	t.Logf("txMoveNeo hash: %s", txMoveNeo.Hash().StringLE())
+	t.Logf("txMoveNeo hex: %s", hex.EncodeToString(txMoveNeo.Bytes()))
+	t.Logf("txMoveGas hash: %s", txMoveGas.Hash().StringLE())

 	require.True(t, bc.GetUtilityTokenBalance(priv0ScriptHash).Cmp(big.NewInt(1000*native.GASFactor)) >= 0)
 	// info for getblockheader rpc tests
@ -245,12 +249,13 @@ func TestCreateBasicChain(t *testing.T) {
 	txDeploy := transaction.New(testchain.Network(), txScript, 100*native.GASFactor)
 	txDeploy.Nonce = getNextNonce()
 	txDeploy.ValidUntilBlock = validUntilBlock
-	txDeploy.Sender = priv0ScriptHash
+	txDeploy.Signers = []transaction.Signer{{Account: priv0ScriptHash}}
 	require.NoError(t, addNetworkFee(bc, txDeploy, acc0))
 	require.NoError(t, acc0.SignTx(txDeploy))
 	b = bc.newBlock(txDeploy)
 	require.NoError(t, bc.AddBlock(b))
 	t.Logf("txDeploy: %s", txDeploy.Hash().StringLE())
+	t.Logf("Block2 hash: %s", b.Hash().StringLE())

 	// Now invoke this contract.
 	script = io.NewBufBinWriter()
@ -259,7 +264,7 @@ func TestCreateBasicChain(t *testing.T) {
 	txInv := transaction.New(testchain.Network(), script.Bytes(), 1*native.GASFactor)
 	txInv.Nonce = getNextNonce()
 	txInv.ValidUntilBlock = validUntilBlock
-	txInv.Sender = priv0ScriptHash
+	txInv.Signers = []transaction.Signer{{Account: priv0ScriptHash}}
 	require.NoError(t, addNetworkFee(bc, txInv, acc0))
 	require.NoError(t, acc0.SignTx(txInv))
 	b = bc.newBlock(txInv)
@ -270,8 +275,7 @@ func TestCreateBasicChain(t *testing.T) {
 	txNeo0to1 := newNEP5Transfer(neoHash, priv0ScriptHash, priv1.GetScriptHash(), 1000)
 	txNeo0to1.Nonce = getNextNonce()
 	txNeo0to1.ValidUntilBlock = validUntilBlock
-	txNeo0to1.Sender = priv0ScriptHash
-	txNeo0to1.Cosigners = []transaction.Cosigner{
+	txNeo0to1.Signers = []transaction.Signer{
 		{
 			Account:          priv0ScriptHash,
 			Scopes:           transaction.CalledByEntry,
@ -290,14 +294,13 @@ func TestCreateBasicChain(t *testing.T) {
 	initTx := transaction.New(testchain.Network(), w.Bytes(), 1*native.GASFactor)
 	initTx.Nonce = getNextNonce()
 	initTx.ValidUntilBlock = validUntilBlock
-	initTx.Sender = priv0ScriptHash
+	initTx.Signers = []transaction.Signer{{Account: priv0ScriptHash}}
 	require.NoError(t, addNetworkFee(bc, initTx, acc0))
 	require.NoError(t, acc0.SignTx(initTx))
 	transferTx := newNEP5Transfer(sh, sh, priv0.GetScriptHash(), 1000)
 	transferTx.Nonce = getNextNonce()
 	transferTx.ValidUntilBlock = validUntilBlock
-	transferTx.Sender = priv0ScriptHash
-	transferTx.Cosigners = []transaction.Cosigner{
+	transferTx.Signers = []transaction.Signer{
 		{
 			Account:          priv0ScriptHash,
 			Scopes:           transaction.CalledByEntry,
@ -315,8 +318,7 @@ func TestCreateBasicChain(t *testing.T) {
 	transferTx = newNEP5Transfer(sh, priv0.GetScriptHash(), priv1.GetScriptHash(), 123)
 	transferTx.Nonce = getNextNonce()
 	transferTx.ValidUntilBlock = validUntilBlock
-	transferTx.Sender = priv0ScriptHash
-	transferTx.Cosigners = []transaction.Cosigner{
+	transferTx.Signers = []transaction.Signer{
 		{
 			Account:          priv0ScriptHash,
 			Scopes:           transaction.CalledByEntry,
@ -357,8 +359,7 @@ func TestCreateBasicChain(t *testing.T) {
 	txSendRaw := newNEP5Transfer(neoHash, priv0ScriptHash, priv1.GetScriptHash(), int64(util.Fixed8FromInt64(1000)))
 	txSendRaw.ValidUntilBlock = validUntilBlock
 	txSendRaw.Nonce = getNextNonce()
-	txSendRaw.Sender = priv0ScriptHash
-	txSendRaw.Cosigners = []transaction.Cosigner{{
+	txSendRaw.Signers = []transaction.Signer{{
 		Account:          priv0ScriptHash,
 		Scopes:           transaction.CalledByEntry,
 		AllowedContracts: nil,
@ -366,7 +367,7 @@ func TestCreateBasicChain(t *testing.T) {
 	}}
 	require.NoError(t, addNetworkFee(bc, txSendRaw, acc0))
 	require.NoError(t, acc0.SignTx(txSendRaw))
-	bw := io.NewBufBinWriter()
+	bw = io.NewBufBinWriter()
 	txSendRaw.EncodeBinary(bw.BinWriter)
 	t.Logf("sendrawtransaction: %s", hex.EncodeToString(bw.Bytes()))
 }
@ -380,16 +381,9 @@ func newNEP5Transfer(sc, from, to util.Uint160, amount int64) *transaction.Trans
 	return transaction.New(testchain.Network(), script, 10000000)
 }

-func addSender(txs ...*transaction.Transaction) error {
+func addSigners(txs ...*transaction.Transaction) {
 	for _, tx := range txs {
-		tx.Sender = neoOwner
-	}
-	return nil
-}
-
-func addCosigners(txs ...*transaction.Transaction) {
-	for _, tx := range txs {
-		tx.Cosigners = []transaction.Cosigner{{
+		tx.Signers = []transaction.Signer{{
 			Account:          neoOwner,
 			Scopes:           transaction.CalledByEntry,
 			AllowedContracts: nil,
@ -424,7 +418,7 @@ func addNetworkFee(bc *Blockchain, tx *transaction.Transaction, sender *wallet.A
 	netFee, sizeDelta := CalculateNetworkFee(sender.Contract.Script)
 	tx.NetworkFee += netFee
 	size += sizeDelta
-	for _, cosigner := range tx.Cosigners {
+	for _, cosigner := range tx.Signers {
 		contract := bc.GetContractState(cosigner.Account)
 		if contract != nil {
 			netFee, sizeDelta = CalculateNetworkFee(contract.Script)
--- a/pkg/core/interop/runtime/witness.go
+++ b/pkg/core/interop/runtime/witness.go
@ -23,7 +23,7 @@ func CheckHashedWitness(ic *interop.Context, hash util.Uint160) (bool, error) {
 }

 func checkScope(d dao.DAO, tx *transaction.Transaction, v vm.ScriptHashGetter, hash util.Uint160) (bool, error) {
-	for _, c := range tx.Cosigners {
+	for _, c := range tx.Signers {
 		if c.Account == hash {
 			if c.Scopes == transaction.Global {
 				return true, nil
--- a/pkg/core/interop_neo_test.go
+++ b/pkg/core/interop_neo_test.go
@ -324,6 +324,7 @@ func createVMAndTX(t *testing.T) (*vm.VM, *transaction.Transaction, *interop.Con
 	})

 	tx.Attributes = attributes
+	tx.Signers = []transaction.Signer{{Account: util.Uint160{1, 2, 3, 4}}}
 	chain := newTestChain(t)
 	context := chain.newInteropContext(trigger.Application, dao.NewSimple(storage.NewMemoryStore(), netmode.UnitTestNet), nil, tx)
 	return v, tx, context, chain
--- a/pkg/core/interop_system.go
+++ b/pkg/core/interop_system.go
@ -167,7 +167,7 @@ func transactionToStackItem(t *transaction.Transaction) stackitem.Item {
 		stackitem.NewByteArray(t.Hash().BytesBE()),
 		stackitem.NewBigInteger(big.NewInt(int64(t.Version))),
 		stackitem.NewBigInteger(big.NewInt(int64(t.Nonce))),
-		stackitem.NewByteArray(t.Sender.BytesBE()),
+		stackitem.NewByteArray(t.Sender().BytesBE()),
 		stackitem.NewBigInteger(big.NewInt(int64(t.SystemFee))),
 		stackitem.NewBigInteger(big.NewInt(int64(t.NetworkFee))),
 		stackitem.NewBigInteger(big.NewInt(int64(t.ValidUntilBlock))),
--- a/pkg/core/interop_system_test.go
+++ b/pkg/core/interop_system_test.go
@ -39,7 +39,7 @@ func TestBCGetTransaction(t *testing.T) {
 		require.Equal(t, tx.Hash().BytesBE(), actual[0].Value().([]byte))
 		require.Equal(t, int64(tx.Version), actual[1].Value().(*big.Int).Int64())
 		require.Equal(t, int64(tx.Nonce), actual[2].Value().(*big.Int).Int64())
-		require.Equal(t, tx.Sender.BytesBE(), actual[3].Value().([]byte))
+		require.Equal(t, tx.Sender().BytesBE(), actual[3].Value().([]byte))
 		require.Equal(t, int64(tx.SystemFee), actual[4].Value().(*big.Int).Int64())
 		require.Equal(t, int64(tx.NetworkFee), actual[5].Value().(*big.Int).Int64())
 		require.Equal(t, int64(tx.ValidUntilBlock), actual[6].Value().(*big.Int).Int64())
--- a/pkg/core/mempool/mem_pool.go
+++ b/pkg/core/mempool/mem_pool.go
@ -109,16 +109,16 @@ func (mp *Pool) containsKey(hash util.Uint256) bool {
 // tryAddSendersFee tries to add system fee and network fee to the total sender`s fee in mempool
 // and returns false if both balance check is required and sender has not enough GAS to pay
 func (mp *Pool) tryAddSendersFee(tx *transaction.Transaction, feer Feer, needCheck bool) bool {
-	senderFee, ok := mp.fees[tx.Sender]
+	senderFee, ok := mp.fees[tx.Sender()]
 	if !ok {
-		senderFee.balance = feer.GetUtilityTokenBalance(tx.Sender)
-		mp.fees[tx.Sender] = senderFee
+		senderFee.balance = feer.GetUtilityTokenBalance(tx.Sender())
+		mp.fees[tx.Sender()] = senderFee
 	}
 	if needCheck && !checkBalance(tx, senderFee) {
 		return false
 	}
 	senderFee.feeSum += tx.SystemFee + tx.NetworkFee
-	mp.fees[tx.Sender] = senderFee
+	mp.fees[tx.Sender()] = senderFee
 	return true
 }

@ -199,9 +199,9 @@ func (mp *Pool) Remove(hash util.Uint256) {
 		} else if num == len(mp.verifiedTxes)-1 {
 			mp.verifiedTxes = mp.verifiedTxes[:num]
 		}
-		senderFee := mp.fees[it.txn.Sender]
+		senderFee := mp.fees[it.txn.Sender()]
 		senderFee.feeSum -= it.txn.SystemFee + it.txn.NetworkFee
-		mp.fees[it.txn.Sender] = senderFee
+		mp.fees[it.txn.Sender()] = senderFee
 	}
 	updateMempoolMetrics(len(mp.verifiedTxes))
 	mp.lock.Unlock()
@ -284,9 +284,9 @@ func (mp *Pool) GetVerifiedTransactions() []*transaction.Transaction {

 // checkTxConflicts is an internal unprotected version of Verify.
 func (mp *Pool) checkTxConflicts(tx *transaction.Transaction, fee Feer) bool {
-	senderFee, ok := mp.fees[tx.Sender]
+	senderFee, ok := mp.fees[tx.Sender()]
 	if !ok {
-		senderFee.balance = fee.GetUtilityTokenBalance(tx.Sender)
+		senderFee.balance = fee.GetUtilityTokenBalance(tx.Sender())
 	}
 	return checkBalance(tx, senderFee)
 }
--- a/pkg/core/mempool/mem_pool_test.go
+++ b/pkg/core/mempool/mem_pool_test.go
@ -31,6 +31,7 @@ func testMemPoolAddRemoveWithFeer(t *testing.T, fs Feer) {
 	mp := NewMemPool(10)
 	tx := transaction.New(netmode.UnitTestNet, []byte{byte(opcode.PUSH1)}, 0)
 	tx.Nonce = 0
+	tx.Signers = []transaction.Signer{{Account: util.Uint160{1, 2, 3}}}
 	_, ok := mp.TryGetValue(tx.Hash())
 	require.Equal(t, false, ok)
 	require.NoError(t, mp.Add(tx, fs))
@ -60,6 +61,7 @@ func TestOverCapacity(t *testing.T) {
 	for i := 0; i < mempoolSize; i++ {
 		tx := transaction.New(netmode.UnitTestNet, []byte{byte(opcode.PUSH1)}, 0)
 		tx.Nonce = uint32(i)
+		tx.Signers = []transaction.Signer{{Account: util.Uint160{1, 2, 3}}}
 		require.NoError(t, mp.Add(tx, fs))
 	}
 	txcnt := uint32(mempoolSize)
@ -75,6 +77,7 @@ func TestOverCapacity(t *testing.T) {
 		})
 		tx.NetworkFee = 10000
 		tx.Nonce = txcnt
+		tx.Signers = []transaction.Signer{{Account: util.Uint160{1, 2, 3}}}
 		txcnt++
 		// size is 84, networkFee is 10000 => feePerByte is 119
 		require.NoError(t, mp.Add(tx, fs))
@ -89,6 +92,7 @@ func TestOverCapacity(t *testing.T) {
 	})
 	tx.NetworkFee = 100
 	tx.Nonce = txcnt
+	tx.Signers = []transaction.Signer{{Account: util.Uint160{1, 2, 3}}}
 	txcnt++
 	require.Error(t, mp.Add(tx, fs))
 	require.Equal(t, mempoolSize, mp.Count())
@ -98,6 +102,7 @@ func TestOverCapacity(t *testing.T) {
 	tx = transaction.New(netmode.UnitTestNet, []byte{byte(opcode.PUSH1)}, 0)
 	tx.Nonce = txcnt
 	tx.NetworkFee = 7000
+	tx.Signers = []transaction.Signer{{Account: util.Uint160{1, 2, 3}}}
 	txcnt++
 	// size is 51 (no attributes), networkFee is 7000 (<10000)
 	// => feePerByte is 137 (>119)
@ -110,6 +115,7 @@ func TestOverCapacity(t *testing.T) {
 		tx := transaction.New(netmode.UnitTestNet, []byte{byte(opcode.PUSH1)}, 0)
 		tx.NetworkFee = 8000
 		tx.Nonce = txcnt
+		tx.Signers = []transaction.Signer{{Account: util.Uint160{1, 2, 3}}}
 		txcnt++
 		require.NoError(t, mp.Add(tx, fs))
 		require.Equal(t, mempoolSize, mp.Count())
@ -119,6 +125,7 @@ func TestOverCapacity(t *testing.T) {
 	tx = transaction.New(netmode.UnitTestNet, []byte{byte(opcode.PUSH1)}, 0)
 	tx.Nonce = txcnt
 	tx.NetworkFee = 7000
+	tx.Signers = []transaction.Signer{{Account: util.Uint160{1, 2, 3}}}
 	require.Error(t, mp.Add(tx, fs))
 	require.Equal(t, mempoolSize, mp.Count())
 	require.Equal(t, true, sort.IsSorted(sort.Reverse(mp.verifiedTxes)))
@ -133,6 +140,7 @@ func TestGetVerified(t *testing.T) {
 	for i := 0; i < mempoolSize; i++ {
 		tx := transaction.New(netmode.UnitTestNet, []byte{byte(opcode.PUSH1)}, 0)
 		tx.Nonce = uint32(i)
+		tx.Signers = []transaction.Signer{{Account: util.Uint160{1, 2, 3}}}
 		txes = append(txes, tx)
 		require.NoError(t, mp.Add(tx, fs))
 	}
@ -157,6 +165,7 @@ func TestRemoveStale(t *testing.T) {
 	for i := 0; i < mempoolSize; i++ {
 		tx := transaction.New(netmode.UnitTestNet, []byte{byte(opcode.PUSH1)}, 0)
 		tx.Nonce = uint32(i)
+		tx.Signers = []transaction.Signer{{Account: util.Uint160{1, 2, 3}}}
 		if i%2 == 0 {
 			txes1 = append(txes1, tx)
 		} else {
@ -186,7 +195,7 @@ func TestMemPoolFees(t *testing.T) {
 	sender0 := util.Uint160{1, 2, 3}
 	tx0 := transaction.New(netmode.UnitTestNet, []byte{byte(opcode.PUSH1)}, 0)
 	tx0.NetworkFee = balance.Int64() + 1
-	tx0.Sender = sender0
+	tx0.Signers = []transaction.Signer{{Account: sender0}}
 	// insufficient funds to add transaction, and balance shouldn't be stored
 	require.Equal(t, false, mp.Verify(tx0, &FeerStub{}))
 	require.Error(t, mp.Add(tx0, &FeerStub{}))
@ -196,7 +205,7 @@ func TestMemPoolFees(t *testing.T) {
 	// no problems with adding another transaction with lower fee
 	tx1 := transaction.New(netmode.UnitTestNet, []byte{byte(opcode.PUSH1)}, 0)
 	tx1.NetworkFee = balancePart.Int64()
-	tx1.Sender = sender0
+	tx1.Signers = []transaction.Signer{{Account: sender0}}
 	require.NoError(t, mp.Add(tx1, &FeerStub{}))
 	require.Equal(t, 1, len(mp.fees))
 	require.Equal(t, utilityBalanceAndFees{
@ -207,7 +216,7 @@ func TestMemPoolFees(t *testing.T) {
 	// balance shouldn't change after adding one more transaction
 	tx2 := transaction.New(netmode.UnitTestNet, []byte{byte(opcode.PUSH1)}, 0)
 	tx2.NetworkFee = new(big.Int).Sub(balance, balancePart).Int64()
-	tx2.Sender = sender0
+	tx2.Signers = []transaction.Signer{{Account: sender0}}
 	require.NoError(t, mp.Add(tx2, &FeerStub{}))
 	require.Equal(t, 2, len(mp.verifiedTxes))
 	require.Equal(t, 1, len(mp.fees))
@ -219,7 +228,7 @@ func TestMemPoolFees(t *testing.T) {
 	// can't add more transactions as we don't have enough GAS
 	tx3 := transaction.New(netmode.UnitTestNet, []byte{byte(opcode.PUSH1)}, 0)
 	tx3.NetworkFee = 1
-	tx3.Sender = sender0
+	tx3.Signers = []transaction.Signer{{Account: sender0}}
 	require.Equal(t, false, mp.Verify(tx3, &FeerStub{}))
 	require.Error(t, mp.Add(tx3, &FeerStub{}))
 	require.Equal(t, 1, len(mp.fees))
--- a/pkg/core/native/native_gas.go
+++ b/pkg/core/native/native_gas.go
@ -88,7 +88,7 @@ func (g *GAS) OnPersist(ic *interop.Context) error {
 	}
 	for _, tx := range ic.Block.Transactions {
 		absAmount := big.NewInt(tx.SystemFee + tx.NetworkFee)
-		g.burn(ic, tx.Sender, absAmount)
+		g.burn(ic, tx.Sender(), absAmount)
 	}
 	validators, err := g.NEO.getNextBlockValidatorsInternal(ic.Chain, ic.DAO)
 	if err != nil {
--- a/pkg/core/native_contract_test.go
+++ b/pkg/core/native_contract_test.go
@ -115,13 +115,13 @@ func TestNativeContract_Invoke(t *testing.T) {
 	tx := transaction.New(chain.GetConfig().Magic, script, testSumPrice*2+10000)
 	validUntil := chain.blockHeight + 1
 	tx.ValidUntilBlock = validUntil
-	require.NoError(t, addSender(tx))
+	addSigners(tx)
 	require.NoError(t, signTx(chain, tx))

 	// Enough for Call and other opcodes, but not enough for "sum" call.
 	tx2 := transaction.New(chain.GetConfig().Magic, script, testSumPrice*2)
 	tx2.ValidUntilBlock = chain.blockHeight + 1
-	require.NoError(t, addSender(tx2))
+	addSigners(tx2)
 	require.NoError(t, signTx(chain, tx2))

 	b := chain.newBlock(tx, tx2)
--- a/pkg/core/native_policy_test.go
+++ b/pkg/core/native_policy_test.go
@ -225,12 +225,8 @@ func invokeNativePolicyMethod(chain *Blockchain, method string, args ...interfac
 	tx := transaction.New(chain.GetConfig().Magic, script, 10000000)
 	validUntil := chain.blockHeight + 1
 	tx.ValidUntilBlock = validUntil
-	err := addSender(tx)
-	if err != nil {
-		return nil, err
-	}
-	addCosigners(tx)
-	err = signTx(chain, tx)
+	addSigners(tx)
+	err := signTx(chain, tx)
 	if err != nil {
 		return nil, err
 	}
--- a/pkg/core/transaction/cosigner.go
+++ b/pkg/core/transaction/cosigner.go
@ -11,8 +11,8 @@ import (
 // The maximum number of AllowedContracts or AllowedGroups
 const maxSubitems = 16

-// Cosigner implements a Transaction cosigner.
-type Cosigner struct {
+// Signer implements a Transaction signer.
+type Signer struct {
 	Account          util.Uint160      `json:"account"`
 	Scopes           WitnessScope      `json:"scopes"`
 	AllowedContracts []util.Uint160    `json:"allowedcontracts,omitempty"`
@ -20,7 +20,7 @@ type Cosigner struct {
 }

 // EncodeBinary implements Serializable interface.
-func (c *Cosigner) EncodeBinary(bw *io.BinWriter) {
+func (c *Signer) EncodeBinary(bw *io.BinWriter) {
 	bw.WriteBytes(c.Account[:])
 	bw.WriteB(byte(c.Scopes))
 	if c.Scopes&CustomContracts != 0 {
@ -32,10 +32,10 @@ func (c *Cosigner) EncodeBinary(bw *io.BinWriter) {
 }

 // DecodeBinary implements Serializable interface.
-func (c *Cosigner) DecodeBinary(br *io.BinReader) {
+func (c *Signer) DecodeBinary(br *io.BinReader) {
 	br.ReadBytes(c.Account[:])
 	c.Scopes = WitnessScope(br.ReadB())
-	if c.Scopes & ^(Global|CalledByEntry|CustomContracts|CustomGroups) != 0 {
+	if c.Scopes & ^(Global|CalledByEntry|CustomContracts|CustomGroups|FeeOnly) != 0 {
 		br.Err = errors.New("unknown witness scope")
 		return
 	}
--- a/pkg/core/transaction/cosigner_test.go
+++ b/pkg/core/transaction/cosigner_test.go
@ -8,21 +8,21 @@ import (
 )

 func TestCosignerEncodeDecode(t *testing.T) {
-	expected := &Cosigner{
+	expected := &Signer{
 		Account:          util.Uint160{1, 2, 3, 4, 5},
 		Scopes:           CustomContracts,
 		AllowedContracts: []util.Uint160{{1, 2, 3, 4}, {6, 7, 8, 9}},
 	}
-	actual := &Cosigner{}
+	actual := &Signer{}
 	testserdes.EncodeDecodeBinary(t, expected, actual)
 }

 func TestCosignerMarshallUnmarshallJSON(t *testing.T) {
-	expected := &Cosigner{
+	expected := &Signer{
 		Account:          util.Uint160{1, 2, 3, 4, 5},
 		Scopes:           CustomContracts,
 		AllowedContracts: []util.Uint160{{1, 2, 3, 4}, {6, 7, 8, 9}},
 	}
-	actual := &Cosigner{}
+	actual := &Signer{}
 	testserdes.MarshalUnmarshalJSON(t, expected, actual)
 }
--- a/pkg/core/transaction/transaction.go
+++ b/pkg/core/transaction/transaction.go
@ -19,9 +19,9 @@ const (
 	// MaxValidUntilBlockIncrement is the upper increment size of blockhain height in blocs after
 	// exceeding that a transaction should fail validation. It is set to be 2102400.
 	MaxValidUntilBlockIncrement = 2102400
-	// MaxCosigners is maximum number of cosigners that can be contained within a transaction.
-	// It is set to be 16.
-	MaxCosigners = 16
+	// MaxAttributes is maximum number of attributes including signers that can be contained
+	// within a transaction. It is set to be 16.
+	MaxAttributes = 16
 )

 // Transaction is a process recorded in the NEO blockchain.
@ -32,9 +32,6 @@ type Transaction struct {
 	// Random number to avoid hash collision.
 	Nonce uint32

-	// Address signed the transaction.
-	Sender util.Uint160
-
 	// Fee to be burned.
 	SystemFee int64

@ -51,8 +48,8 @@ type Transaction struct {
 	// Transaction attributes.
 	Attributes []Attribute

-	// Transaction cosigners (not include Sender).
-	Cosigners []Cosigner
+	// Transaction signers list (starts with Sender).
+	Signers []Signer

 	// The scripts that comes with this transaction.
 	// Scripts exist out of the verification script
@ -96,7 +93,7 @@ func New(network netmode.Magic, script []byte, gas int64) *Transaction {
 		Script:     script,
 		SystemFee:  gas,
 		Attributes: []Attribute{},
-		Cosigners:  []Cosigner{},
+		Signers:    []Signer{},
 		Scripts:    []Witness{},
 		Network:    network,
 	}
@ -131,7 +128,6 @@ func (t *Transaction) decodeHashableFields(br *io.BinReader) {
 		return
 	}
 	t.Nonce = br.ReadU32LE()
-	t.Sender.DecodeBinary(br)
 	t.SystemFee = int64(br.ReadU64LE())
 	if t.SystemFee < 0 {
 		br.Err = errors.New("negative system fee")
@ -148,22 +144,25 @@ func (t *Transaction) decodeHashableFields(br *io.BinReader) {
 	}
 	t.ValidUntilBlock = br.ReadU32LE()

-	br.ReadArray(&t.Attributes)
-
-	br.ReadArray(&t.Cosigners, MaxCosigners)
-	for i := 0; i < len(t.Cosigners); i++ {
-		if t.Cosigners[i].Scopes == FeeOnly {
+	br.ReadArray(&t.Signers, MaxAttributes)
+	if len(t.Signers) == 0 {
+		br.Err = errors.New("signers array should contain sender")
+		return
+	}
+	for i := 0; i < len(t.Signers); i++ {
+		if i > 0 && t.Signers[i].Scopes == FeeOnly {
 			br.Err = errors.New("FeeOnly scope can be used only for sender")
 			return
 		}
-		for j := i + 1; j < len(t.Cosigners); j++ {
-			if t.Cosigners[i].Account.Equals(t.Cosigners[j].Account) {
-				br.Err = errors.New("transaction cosigners should be unique")
+		for j := i + 1; j < len(t.Signers); j++ {
+			if t.Signers[i].Account.Equals(t.Signers[j].Account) {
+				br.Err = errors.New("transaction signers should be unique")
 				return
 			}
 		}
 	}

+	br.ReadArray(&t.Attributes, MaxAttributes-len(t.Signers))
 	t.Script = br.ReadVarBytes()
 	if br.Err == nil && len(t.Script) == 0 {
 		br.Err = errors.New("no script")
@ -201,17 +200,11 @@ func (t *Transaction) encodeHashableFields(bw *io.BinWriter) {
 	}
 	bw.WriteB(byte(t.Version))
 	bw.WriteU32LE(t.Nonce)
-	t.Sender.EncodeBinary(bw)
 	bw.WriteU64LE(uint64(t.SystemFee))
 	bw.WriteU64LE(uint64(t.NetworkFee))
 	bw.WriteU32LE(t.ValidUntilBlock)
-
-	// Attributes
+	bw.WriteArray(t.Signers)
 	bw.WriteArray(t.Attributes)
-
-	// Cosigners
-	bw.WriteArray(t.Cosigners)
-
 	bw.WriteVarBytes(t.Script)
 }

@ -297,6 +290,15 @@ func (t *Transaction) FeePerByte() int64 {
 	return t.feePerByte
 }

+// Sender returns the sender of the transaction which is always on the first place
+// in the transaction's signers list.
+func (t *Transaction) Sender() util.Uint160 {
+	if len(t.Signers) == 0 {
+		panic("transaction does not have signers")
+	}
+	return t.Signers[0].Account
+}
+
 // transactionJSON is a wrapper for Transaction and
 // used for correct marhalling of transaction.Data
 type transactionJSON struct {
@ -309,7 +311,7 @@ type transactionJSON struct {
 	NetworkFee      int64        `json:"netfee,string"`
 	ValidUntilBlock uint32       `json:"validuntilblock"`
 	Attributes      []Attribute  `json:"attributes"`
-	Cosigners       []Cosigner   `json:"cosigners"`
+	Signers         []Signer     `json:"signers"`
 	Script          []byte       `json:"script"`
 	Scripts         []Witness    `json:"witnesses"`
 }
@ -321,10 +323,10 @@ func (t *Transaction) MarshalJSON() ([]byte, error) {
 		Size:            io.GetVarSize(t),
 		Version:         t.Version,
 		Nonce:           t.Nonce,
-		Sender:          address.Uint160ToString(t.Sender),
+		Sender:          address.Uint160ToString(t.Sender()),
 		ValidUntilBlock: t.ValidUntilBlock,
 		Attributes:      t.Attributes,
-		Cosigners:       t.Cosigners,
+		Signers:         t.Signers,
 		Script:          t.Script,
 		Scripts:         t.Scripts,
 		SystemFee:       t.SystemFee,
@ -343,15 +345,10 @@ func (t *Transaction) UnmarshalJSON(data []byte) error {
 	t.Nonce = tx.Nonce
 	t.ValidUntilBlock = tx.ValidUntilBlock
 	t.Attributes = tx.Attributes
-	t.Cosigners = tx.Cosigners
+	t.Signers = tx.Signers
 	t.Scripts = tx.Scripts
 	t.SystemFee = tx.SystemFee
 	t.NetworkFee = tx.NetworkFee
-	sender, err := address.StringToUint160(tx.Sender)
-	if err != nil {
-		return errors.New("cannot unmarshal tx: bad sender")
-	}
-	t.Sender = sender
 	t.Script = tx.Script
 	if t.Hash() != tx.TxID {
 		return errors.New("txid doesn't match transaction hash")
--- a/pkg/core/transaction/transaction_test.go
+++ b/pkg/core/transaction/transaction_test.go
@ -6,6 +6,7 @@ import (

 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"github.com/nspcc-dev/neo-go/pkg/internal/testserdes"
+	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@ -64,6 +65,7 @@ func TestDecodeEncodeInvocationTX(t *testing.T) {
 func TestNew(t *testing.T) {
 	script := []byte{0x51}
 	tx := New(netmode.UnitTestNet, script, 1)
+	tx.Signers = []Signer{{Account: util.Uint160{1, 2, 3}}}
 	assert.Equal(t, int64(1), tx.SystemFee)
 	assert.Equal(t, script, tx.Script)
 	// Update hash fields to match tx2 that is gonna autoupdate them on decode.
@ -75,6 +77,7 @@ func TestNewTransactionFromBytes(t *testing.T) {
 	script := []byte{0x51}
 	tx := New(netmode.UnitTestNet, script, 1)
 	tx.NetworkFee = 123
+	tx.Signers = []Signer{{Account: util.Uint160{1, 2, 3}}}
 	data, err := testserdes.EncodeBinary(tx)
 	require.NoError(t, err)

@ -106,6 +109,7 @@ func TestDecodingTXWithNoScript(t *testing.T) {
 func TestMarshalUnmarshalJSONInvocationTX(t *testing.T) {
 	tx := &Transaction{
 		Version:    0,
+		Signers:    []Signer{{Account: util.Uint160{1, 2, 3}}},
 		Script:     []byte{1, 2, 3, 4},
 		Attributes: []Attribute{},
 		Scripts:    []Witness{},
--- a/pkg/core/transaction/witness_scope.go
+++ b/pkg/core/transaction/witness_scope.go
@ -7,7 +7,7 @@ import (
 	"strings"
 )

-// WitnessScope represents set of witness flags for Transaction cosigner.
+// WitnessScope represents set of witness flags for Transaction signer.
 type WitnessScope byte

 const (
--- a/pkg/core/util.go
+++ b/pkg/core/util.go
@ -78,7 +78,12 @@ func deployNativeContracts(magic netmode.Magic) *transaction.Transaction {
 	script := buf.Bytes()
 	tx := transaction.New(magic, script, 0)
 	tx.Nonce = 0
-	tx.Sender = hash.Hash160([]byte{byte(opcode.PUSH1)})
+	tx.Signers = []transaction.Signer{
+		{
+			Account: hash.Hash160([]byte{byte(opcode.PUSH1)}),
+			Scopes:  transaction.FeeOnly,
+		},
+	}
 	tx.Scripts = []transaction.Witness{
 		{
 			InvocationScript:   []byte{},
--- a/pkg/core/util_test.go
+++ b/pkg/core/util_test.go
@ -21,7 +21,7 @@ func TestGenesisBlockMainNet(t *testing.T) {
 	// have been changed. Consequently, hash of the genesis block has been changed.
 	// Update expected genesis block hash for better times.
 	// Old hash is "d42561e3d30e15be6400b6df2f328e02d2bf6354c41dce433bc57687c82144bf"
-	expect := "94e61af2441145cc251752707a58107850328a48bb095fd175ca2f8513ab5676"
+	expect := "ecaee33262f1bc7c7c28f2b25b54a5d61d50670871f45c0c6fe755a40cbde4a8"
 	assert.Equal(t, expect, block.Hash().StringLE())
 }

--- a/pkg/rpc/client/nep5.go
+++ b/pkg/rpc/client/nep5.go
@ -131,7 +131,7 @@ func (c *Client) CreateNEP5MultiTransferTx(acc *wallet.Account, token util.Uint1
 	}

 	script := w.Bytes()
-	result, err := c.InvokeScript(script, []transaction.Cosigner{
+	result, err := c.InvokeScript(script, []transaction.Signer{
 		{
 			Account: from,
 			Scopes:  transaction.CalledByEntry,
@ -141,8 +141,7 @@ func (c *Client) CreateNEP5MultiTransferTx(acc *wallet.Account, token util.Uint1
 		return nil, fmt.Errorf("can't add system fee to transaction: %v", err)
 	}
 	tx := transaction.New(c.opts.Network, script, result.GasConsumed)
-	tx.Sender = from
-	tx.Cosigners = []transaction.Cosigner{
+	tx.Signers = []transaction.Signer{
 		{
 			Account: from,
 			Scopes:  transaction.CalledByEntry,
--- a/pkg/rpc/client/rpc.go
+++ b/pkg/rpc/client/rpc.go
@ -345,31 +345,31 @@ func (c *Client) GetVersion() (*result.Version, error) {

 // InvokeScript returns the result of the given script after running it true the VM.
 // NOTE: This is a test invoke and will not affect the blockchain.
-func (c *Client) InvokeScript(script []byte, cosigners []transaction.Cosigner) (*result.Invoke, error) {
+func (c *Client) InvokeScript(script []byte, signers []transaction.Signer) (*result.Invoke, error) {
 	var p = request.NewRawParams(hex.EncodeToString(script))
-	return c.invokeSomething("invokescript", p, cosigners)
+	return c.invokeSomething("invokescript", p, signers)
 }

 // InvokeFunction returns the results after calling the smart contract scripthash
 // with the given operation and parameters.
 // NOTE: this is test invoke and will not affect the blockchain.
-func (c *Client) InvokeFunction(contract util.Uint160, operation string, params []smartcontract.Parameter, cosigners []transaction.Cosigner) (*result.Invoke, error) {
+func (c *Client) InvokeFunction(contract util.Uint160, operation string, params []smartcontract.Parameter, signers []transaction.Signer) (*result.Invoke, error) {
 	var p = request.NewRawParams(contract.StringLE(), operation, params)
-	return c.invokeSomething("invokefunction", p, cosigners)
+	return c.invokeSomething("invokefunction", p, signers)
 }

 // invokeSomething is an inner wrapper for Invoke* functions
-func (c *Client) invokeSomething(method string, p request.RawParams, cosigners []transaction.Cosigner) (*result.Invoke, error) {
+func (c *Client) invokeSomething(method string, p request.RawParams, signers []transaction.Signer) (*result.Invoke, error) {
 	var resp = new(result.Invoke)
-	if cosigners != nil {
-		p.Values = append(p.Values, cosigners)
+	if signers != nil {
+		p.Values = append(p.Values, signers)
 	}
 	if err := c.performRequest(method, p, resp); err != nil {
 		// Retry with old-fashioned hashes (see neo/neo-modules#260).
-		if cosigners != nil {
-			var hashes = make([]util.Uint160, len(cosigners))
-			for i := range cosigners {
-				hashes[i] = cosigners[i].Account
+		if signers != nil {
+			var hashes = make([]util.Uint160, len(signers))
+			for i := range signers {
+				hashes[i] = signers[i].Account
 			}
 			p.Values[len(p.Values)-1] = hashes
 			err = c.performRequest(method, p, resp)
@ -419,13 +419,18 @@ func (c *Client) SubmitBlock(b block.Block) (util.Uint256, error) {
 // SignAndPushInvocationTx signs and pushes given script as an invocation
 // transaction  using given wif to sign it and spending the amount of gas
 // specified. It returns a hash of the invocation transaction and an error.
-func (c *Client) SignAndPushInvocationTx(script []byte, acc *wallet.Account, sysfee int64, netfee util.Fixed8, cosigners []transaction.Cosigner) (util.Uint256, error) {
+func (c *Client) SignAndPushInvocationTx(script []byte, acc *wallet.Account, sysfee int64, netfee util.Fixed8, cosigners []transaction.Signer) (util.Uint256, error) {
 	var txHash util.Uint256
 	var err error

 	tx := transaction.New(c.opts.Network, script, sysfee)
 	tx.SystemFee = sysfee
-	tx.Cosigners = cosigners
+
+	addr, err := address.StringToUint160(acc.Address)
+	if err != nil {
+		return txHash, errors.Wrap(err, "failed to get address")
+	}
+	tx.Signers = getSigners(addr, cosigners)

 	validUntilBlock, err := c.CalculateValidUntilBlock()
 	if err != nil {
@ -433,12 +438,6 @@ func (c *Client) SignAndPushInvocationTx(script []byte, acc *wallet.Account, sys
 	}
 	tx.ValidUntilBlock = validUntilBlock

-	addr, err := address.StringToUint160(acc.Address)
-	if err != nil {
-		return txHash, errors.Wrap(err, "failed to get address")
-	}
-	tx.Sender = addr
-
 	err = c.AddNetworkFee(tx, int64(netfee), acc)
 	if err != nil {
 		return txHash, errors.Wrapf(err, "failed to add network fee")
@ -458,6 +457,27 @@ func (c *Client) SignAndPushInvocationTx(script []byte, acc *wallet.Account, sys
 	return txHash, nil
 }

+// getSigners returns an array of transaction signers from given sender and cosigners.
+// If cosigners list already contains sender, the sender will be placed at the start of
+// the list.
+func getSigners(sender util.Uint160, cosigners []transaction.Signer) []transaction.Signer {
+	s := transaction.Signer{
+		Account: sender,
+		Scopes:  transaction.FeeOnly,
+	}
+	for i, c := range cosigners {
+		if c.Account == sender {
+			if i == 0 {
+				return cosigners
+			}
+			s.Scopes = c.Scopes
+			cosigners = append(cosigners[:i], cosigners[i+1:]...)
+			break
+		}
+	}
+	return append([]transaction.Signer{s}, cosigners...)
+}
+
 // ValidateAddress verifies that the address is a correct NEO address.
 func (c *Client) ValidateAddress(address string) error {
 	var (
@ -513,7 +533,7 @@ func (c *Client) AddNetworkFee(tx *transaction.Transaction, extraFee int64, acc
 		tx.NetworkFee += netFee
 		size += sizeDelta
 	}
-	for _, cosigner := range tx.Cosigners {
+	for _, cosigner := range tx.Signers {
 		script := acc.Contract.Script
 		if !cosigner.Account.Equals(hash.Hash160(acc.Contract.Script)) {
 			contract, err := c.GetContractState(cosigner.Account)
--- a/pkg/rpc/client/rpc_test.go
+++ b/pkg/rpc/client/rpc_test.go
@ -41,17 +41,17 @@ type rpcClientTestCase struct {
 	check          func(t *testing.T, c *Client, result interface{})
 }

-const hexB1 = "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"
+const hexB1 = "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"

-const hexTxMoveNeo = "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"
+const hexTxMoveNeo = "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"

-const b1Verbose = `{"id":5,"jsonrpc":"2.0","result":{"size":1681,"nextblockhash":"0x45f62d72e37b074ecdc9f687222b0f91ec98d6d9af4429a2caa2e076a9196b0d","confirmations":6,"hash":"0x4f2c5539b0213ea444608cc217c5cb191255c1858ccd051ad9a36f08df26a288","version":0,"previousblockhash":"0x56fd4244e552536a4dae38b1446f8689b6f123b116e6c37028cac4439cb1aa8a","merkleroot":"0xf9dce467385206ad220a8b85d238f77239766eaffffed19955e3e47d24071140","time":1592472500001,"index":1,"nextconsensus":"Nbb1qkwcwNSBs9pAnrVVrnFbWnbWBk91U2","witnesses":[{"invocation":"DEAPAetjcaE1Un3bIFoNrh9p0tMkg3zOEovq2QMwkYg/nOIebXWaQPaQdGWSsCHTl/CI47e0F/zvc80b/cKAB2lSDECE965dn1igmqVu6y8oJ0SlmoLRfjvg6xx/VObo33liDiYIGRusVygKg22y7Cp3bQfkPxa8dsR9NIsPzQnVbHwyDEArlbTjnsNRYqZAeV/yI+kt7JU5CgcutFf2pDIwUvgHMVF+DfAp5KRXIE93f1JhxqSojUbUw6vexjWm7tWA1sd/DEC5c1dFsd15WiWMMdjm+ofVz8Lps6SJDWENM7z4M7ZMWLDFzqF/OnEo8QZe0ZPmNpcVkPGT8ovdHu67vB/m587l","verification":"EwwhAhA6f33QFlWFl/eWDSfFFqQ5T9loueZRVetLAT5AQEBuDCECp7xV/oaE4BGXaNEEujB5W9zIZhnoZK3SYVZyPtGFzWIMIQKzYiv0AXvf4xfFiu1fTHU/IGt9uJYEb6fXdLvEv3+NwgwhA9kMB99j5pDOd5EuEKtRrMlEtmhgI3tgjE+PgwnnHuaZFAtBMHOzuw=="}],"consensusdata":{"primary":0,"nonce":"0000000000000457"},"tx":[{"hash":"0x7fb05b593cf4b1eb2d9a283c5488ca1bfe61191b5775bafa43b8647e7b20f22c","size":575,"version":0,"nonce":2,"sender":"Nbb1qkwcwNSBs9pAnrVVrnFbWnbWBk91U2","sysfee":"0","netfee":"876350","validuntilblock":1200,"attributes":[],"cosigners":[{"account":"0x4138145d67638db97b402ee0b6751ef16253ecab","scopes":"CalledByEntry"}],"script":"Ahjd9QUMFDFuhRA5AZ0538LDfWw/7hn9WAmHDBSr7FNi8R51tuAuQHu5jWNnXRQ4QRPADAh0cmFuc2ZlcgwUiXcg2M129PAKv6N8Dt2InCCP3ptBYn1bUjg=","witnesses":[{"invocation":"DECub8BP5LbCIhjKlhfJjWB9nsmx+vjP3DORvsSFrnaxGtxsxqvrMaULU26oBz5nTWKlVm/OXgoM6wcYy5ccGuPQDEBgMHG3JaWNBSytev2I6ZsnuquTGv1btQ0W4iQzWqtFAXCqviUdPAxq0/Md1+m4myCbqr5aHi+liL2BGPnippYPDEDXKvzznmY9ui1w+4w2oJ0aamrQ0v04yFeo59xx4rmHETJODS7GQf5olrpjuoDT6jQcGq0R4IL7GI7gfiFbQDGxDECa+ygItgKGpWNDt//O8ouyqwxZVgPnMjteWwucHBDt+lxAdU2SGGXLb9cWaKIGs3oesQwAKan806hWrtB3Qs0/","verification":"EwwhAhA6f33QFlWFl/eWDSfFFqQ5T9loueZRVetLAT5AQEBuDCECp7xV/oaE4BGXaNEEujB5W9zIZhnoZK3SYVZyPtGFzWIMIQKzYiv0AXvf4xfFiu1fTHU/IGt9uJYEb6fXdLvEv3+NwgwhA9kMB99j5pDOd5EuEKtRrMlEtmhgI3tgjE+PgwnnHuaZFAtBMHOzuw=="}]},{"hash":"0xb661d5e4d9e41c3059b068f8abb6f1566a47ec800879e34c0ebd2799781a2760","size":579,"version":0,"nonce":3,"sender":"Nbb1qkwcwNSBs9pAnrVVrnFbWnbWBk91U2","sysfee":"0","netfee":"880350","validuntilblock":1200,"attributes":[],"cosigners":[{"account":"0x4138145d67638db97b402ee0b6751ef16253ecab","scopes":"CalledByEntry"}],"script":"AwDodkgXAAAADBQxboUQOQGdOd/Cw31sP+4Z/VgJhwwUq+xTYvEedbbgLkB7uY1jZ10UOEETwAwIdHJhbnNmZXIMFDt9NxHG8Mz5sdypA9G/odiW8SOMQWJ9W1I4","witnesses":[{"invocation":"DECHEOe12Kxs2NCdb7Nb8tzOX1+zhZXdttBKVwvJJbwsVac83188taH+sKzE8myLvKbEPfO0qYuMPCyAnC8JbrJaDEDBhsECy/cjE/2U31B3/Fu+/NMiJ+0hWaR6RllId/o58zDYIjtFqiSv8AW+u1skJ6UMjE3oYY59ewDXPYNsRJQuDECiQ7W1Zb1LwvC7ES92JPazUUwSQTxalSMIGfrOP3YPA/y5axiPmAOKPyUWhrU6iNaXRPTkqYXmKXADqAzbFp6ADEBKlR5hrJnV7jGDHREXVK23EbSpBgqVJP44OpB3GEPNsJY4JnQCeofyoVqDvXfesrKrH+iz3m5UYpPvPfmxEp4o","verification":"EwwhAhA6f33QFlWFl/eWDSfFFqQ5T9loueZRVetLAT5AQEBuDCECp7xV/oaE4BGXaNEEujB5W9zIZhnoZK3SYVZyPtGFzWIMIQKzYiv0AXvf4xfFiu1fTHU/IGt9uJYEb6fXdLvEv3+NwgwhA9kMB99j5pDOd5EuEKtRrMlEtmhgI3tgjE+PgwnnHuaZFAtBMHOzuw=="}]}]}}`
+const b1Verbose = `{"id":5,"jsonrpc":"2.0","result":{"size":1641,"nextblockhash":"0x003abea54aa3c5edba7e33fb7ca96452cb65ff8cd36ce1cdfd412a6c4d3ea38a","confirmations":6,"hash":"0xd9518e322440714b0564d6f84a9a39b527b5480e4e7f7932895777a4c8fa0a9e","version":0,"previousblockhash":"0xa496577895eb8c227bb866dc44f99f21c0cf06417ca8f2a877cc5d761a50dac0","merkleroot":"0x2b0f84636d814f3a952de145c8f4028f5664132f2719f5902e1884c9fba59806","time":1596101407001,"index":1,"nextconsensus":"NUVPACMnKFhpuHjsRjhUvXz1XhqfGZYVtY","witnesses":[{"invocation":"DEANAGtuw7+VLVNvmpESGL4+xqlKgBSIWmMBEtABi86ixft2Q7AcaOC89M+yKVIuTel9doVJcCvfx93CcQ63DZqCDEBtwUEkjuzP9h8ZTL0GEKfGr01pazmh8s2TswJge5sAGryYE/+kjw5NCLFmowhPU73qUYQ9jq1zMNMXF+Deqxp/DEDkytkkwJec5n4x2+l5zsZHT6QTXJsByZOWXaGPVJKK8CeDccZba7Mf4MdSkWqSt61xUtlgM2Iqhe/Iuokf/ZEXDEAOH72S12CuAxVu0XNGyj3cgMtad+Bghxvr16T9+ELaWkpR4ko26FdStYC2XiCkzanXTtAD1Id5rREsxfFeKb83","verification":"EwwhAhA6f33QFlWFl/eWDSfFFqQ5T9loueZRVetLAT5AQEBuDCECp7xV/oaE4BGXaNEEujB5W9zIZhnoZK3SYVZyPtGFzWIMIQKzYiv0AXvf4xfFiu1fTHU/IGt9uJYEb6fXdLvEv3+NwgwhA9kMB99j5pDOd5EuEKtRrMlEtmhgI3tgjE+PgwnnHuaZFAtBE43vrw=="}],"consensusdata":{"primary":0,"nonce":"0000000000000457"},"tx":[{"hash":"0x32f9bd3a2707475407c41bf5daacf9560e25ed74f6d85b3afb2ef72edb2325ba","size":555,"version":0,"nonce":2,"sender":"NUVPACMnKFhpuHjsRjhUvXz1XhqfGZYVtY","sysfee":"10000000","netfee":"4488350","validuntilblock":1200,"attributes":[],"signers":[{"account":"0x95307cb9cc8c4578cef9f6845895eb7aa8be125e","scopes":"CalledByEntry"}],"script":"Ahjd9QUMFKqKz4WdT+QCs05nPyFWgheWpIjrDBReEr6oeuuVWIT2+c54RYzMuXwwlRPADAh0cmFuc2ZlcgwUJQWey0h406h1+RxRzt7TMNRXX95BYn1bUjg=","witnesses":[{"invocation":"DEAIcSUsAtRql4t+IEeo+p4+YI7bA6PG+1xxUkPIb2vNlaMl4PumjQVFT+bg2ldxCYa6zccoc4n0Gfryi82EhGpGDECR4fQDr4njo94mF6/GA+OH0Y5k735yGMEZHs96586BRp6f0AQxfmIPvLcS4Yero9p0zgVl9BDg3TxU5piRylR5DEAcjOT7JjEwNRnKgDDkXfh63Yc3MorMbdb2asTiDu0aexy5M5XcikA1jypJT4wkhxjp0rrgFZRSzeYhwV0Klz+yDECIopKxLd4p+hLHxFq07WffXd++sN0WIRWzvMJncCrJqSP8zz65r8TGFFzvZMdGelWKO7KhBOhIK6wryuWNlaDI","verification":"EwwhAhA6f33QFlWFl/eWDSfFFqQ5T9loueZRVetLAT5AQEBuDCECp7xV/oaE4BGXaNEEujB5W9zIZhnoZK3SYVZyPtGFzWIMIQKzYiv0AXvf4xfFiu1fTHU/IGt9uJYEb6fXdLvEv3+NwgwhA9kMB99j5pDOd5EuEKtRrMlEtmhgI3tgjE+PgwnnHuaZFAtBE43vrw=="}]},{"hash":"0xd35d6386ec2f29b90839536f6af9466098d1665e951cdd0a20db6b4629b08369","size":559,"version":0,"nonce":3,"sender":"NUVPACMnKFhpuHjsRjhUvXz1XhqfGZYVtY","sysfee":"10000000","netfee":"4492350","validuntilblock":1200,"attributes":[],"signers":[{"account":"0x95307cb9cc8c4578cef9f6845895eb7aa8be125e","scopes":"CalledByEntry"}],"script":"AwDodkgXAAAADBSqis+FnU/kArNOZz8hVoIXlqSI6wwUXhK+qHrrlViE9vnOeEWMzLl8MJUTwAwIdHJhbnNmZXIMFLyvQdaEx9StbuDZnalwe50fDI5mQWJ9W1I4","witnesses":[{"invocation":"DECKUPl9d502XPI564EC2BroqpN274uV3n1z6kCBCmbS715lzmPbh24LESMsAP2TFohhdhm16aDfNsPi5tkB/FE4DEDzJFts9VYc1lIivGAZZSxACzAV/96Kn2WAaS3bDIlAJHCShsfz+Rn3NuvMyutujYM4vyEipAX9gkjcvFWGKRObDECkI883onhG9aYTxwQWDxsmofuiooRJOic/cJ1H8nqUEvMqATYKgdHaBOJBVYsKq9M9oUv/fj6JFbMDrcasvpiaDECEqkq2b50aEc1NGM9DBAsYLEeZHrM1BwX3a2tBOeeD/KLtmTga1IZogsZgpis2BOToZO6LuN9FJYcn+/iGcC5u","verification":"EwwhAhA6f33QFlWFl/eWDSfFFqQ5T9loueZRVetLAT5AQEBuDCECp7xV/oaE4BGXaNEEujB5W9zIZhnoZK3SYVZyPtGFzWIMIQKzYiv0AXvf4xfFiu1fTHU/IGt9uJYEb6fXdLvEv3+NwgwhA9kMB99j5pDOd5EuEKtRrMlEtmhgI3tgjE+PgwnnHuaZFAtBE43vrw=="}]}]}}`

-const hexHeader1 = "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"
+const hexHeader1 = "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"

-const header1Verbose = `{"id":5,"jsonrpc":"2.0","result":{"hash":"0x4f2c5539b0213ea444608cc217c5cb191255c1858ccd051ad9a36f08df26a288","size":518,"version":0,"previousblockhash":"0x56fd4244e552536a4dae38b1446f8689b6f123b116e6c37028cac4439cb1aa8a","merkleroot":"0xf9dce467385206ad220a8b85d238f77239766eaffffed19955e3e47d24071140","time":1592472500001,"index":1,"nextconsensus":"Nbb1qkwcwNSBs9pAnrVVrnFbWnbWBk91U2","witnesses":[{"invocation":"DEAPAetjcaE1Un3bIFoNrh9p0tMkg3zOEovq2QMwkYg/nOIebXWaQPaQdGWSsCHTl/CI47e0F/zvc80b/cKAB2lSDECE965dn1igmqVu6y8oJ0SlmoLRfjvg6xx/VObo33liDiYIGRusVygKg22y7Cp3bQfkPxa8dsR9NIsPzQnVbHwyDEArlbTjnsNRYqZAeV/yI+kt7JU5CgcutFf2pDIwUvgHMVF+DfAp5KRXIE93f1JhxqSojUbUw6vexjWm7tWA1sd/DEC5c1dFsd15WiWMMdjm+ofVz8Lps6SJDWENM7z4M7ZMWLDFzqF/OnEo8QZe0ZPmNpcVkPGT8ovdHu67vB/m587l","verification":"EwwhAhA6f33QFlWFl/eWDSfFFqQ5T9loueZRVetLAT5AQEBuDCECp7xV/oaE4BGXaNEEujB5W9zIZhnoZK3SYVZyPtGFzWIMIQKzYiv0AXvf4xfFiu1fTHU/IGt9uJYEb6fXdLvEv3+NwgwhA9kMB99j5pDOd5EuEKtRrMlEtmhgI3tgjE+PgwnnHuaZFAtBMHOzuw=="}],"confirmations":6,"nextblockhash":"0x45f62d72e37b074ecdc9f687222b0f91ec98d6d9af4429a2caa2e076a9196b0d"}}`
+const header1Verbose = `{"id":5,"jsonrpc":"2.0","result":{"hash":"0xd9518e322440714b0564d6f84a9a39b527b5480e4e7f7932895777a4c8fa0a9e","size":518,"version":0,"previousblockhash":"0xa496577895eb8c227bb866dc44f99f21c0cf06417ca8f2a877cc5d761a50dac0","merkleroot":"0x2b0f84636d814f3a952de145c8f4028f5664132f2719f5902e1884c9fba59806","time":1596101407001,"index":1,"nextconsensus":"NUVPACMnKFhpuHjsRjhUvXz1XhqfGZYVtY","witnesses":[{"invocation":"DEANAGtuw7+VLVNvmpESGL4+xqlKgBSIWmMBEtABi86ixft2Q7AcaOC89M+yKVIuTel9doVJcCvfx93CcQ63DZqCDEBtwUEkjuzP9h8ZTL0GEKfGr01pazmh8s2TswJge5sAGryYE/+kjw5NCLFmowhPU73qUYQ9jq1zMNMXF+Deqxp/DEDkytkkwJec5n4x2+l5zsZHT6QTXJsByZOWXaGPVJKK8CeDccZba7Mf4MdSkWqSt61xUtlgM2Iqhe/Iuokf/ZEXDEAOH72S12CuAxVu0XNGyj3cgMtad+Bghxvr16T9+ELaWkpR4ko26FdStYC2XiCkzanXTtAD1Id5rREsxfFeKb83","verification":"EwwhAhA6f33QFlWFl/eWDSfFFqQ5T9loueZRVetLAT5AQEBuDCECp7xV/oaE4BGXaNEEujB5W9zIZhnoZK3SYVZyPtGFzWIMIQKzYiv0AXvf4xfFiu1fTHU/IGt9uJYEb6fXdLvEv3+NwgwhA9kMB99j5pDOd5EuEKtRrMlEtmhgI3tgjE+PgwnnHuaZFAtBE43vrw=="}],"confirmations":6,"nextblockhash":"0x003abea54aa3c5edba7e33fb7ca96452cb65ff8cd36ce1cdfd412a6c4d3ea38a"}}`

-const txMoveNeoVerbose = `{"id":5,"jsonrpc":"2.0","result":{"blockhash":"0x4f2c5539b0213ea444608cc217c5cb191255c1858ccd051ad9a36f08df26a288","confirmations":6,"blocktime":1592472500001,"hash":"0x7fb05b593cf4b1eb2d9a283c5488ca1bfe61191b5775bafa43b8647e7b20f22c","size":575,"version":0,"nonce":2,"sender":"Nbb1qkwcwNSBs9pAnrVVrnFbWnbWBk91U2","sysfee":"0","netfee":"876350","validuntilblock":1200,"attributes":[],"cosigners":[{"account":"0x4138145d67638db97b402ee0b6751ef16253ecab","scopes":"CalledByEntry"}],"script":"Ahjd9QUMFDFuhRA5AZ0538LDfWw/7hn9WAmHDBSr7FNi8R51tuAuQHu5jWNnXRQ4QRPADAh0cmFuc2ZlcgwUiXcg2M129PAKv6N8Dt2InCCP3ptBYn1bUjg=","witnesses":[{"invocation":"DECub8BP5LbCIhjKlhfJjWB9nsmx+vjP3DORvsSFrnaxGtxsxqvrMaULU26oBz5nTWKlVm/OXgoM6wcYy5ccGuPQDEBgMHG3JaWNBSytev2I6ZsnuquTGv1btQ0W4iQzWqtFAXCqviUdPAxq0/Md1+m4myCbqr5aHi+liL2BGPnippYPDEDXKvzznmY9ui1w+4w2oJ0aamrQ0v04yFeo59xx4rmHETJODS7GQf5olrpjuoDT6jQcGq0R4IL7GI7gfiFbQDGxDECa+ygItgKGpWNDt//O8ouyqwxZVgPnMjteWwucHBDt+lxAdU2SGGXLb9cWaKIGs3oesQwAKan806hWrtB3Qs0/","verification":"EwwhAhA6f33QFlWFl/eWDSfFFqQ5T9loueZRVetLAT5AQEBuDCECp7xV/oaE4BGXaNEEujB5W9zIZhnoZK3SYVZyPtGFzWIMIQKzYiv0AXvf4xfFiu1fTHU/IGt9uJYEb6fXdLvEv3+NwgwhA9kMB99j5pDOd5EuEKtRrMlEtmhgI3tgjE+PgwnnHuaZFAtBMHOzuw=="}]}}`
+const txMoveNeoVerbose = `{"id":5,"jsonrpc":"2.0","result":{"blockhash":"0xd9518e322440714b0564d6f84a9a39b527b5480e4e7f7932895777a4c8fa0a9e","confirmations":6,"blocktime":1596101407001,"vmstate":"","hash":"0x32f9bd3a2707475407c41bf5daacf9560e25ed74f6d85b3afb2ef72edb2325ba","size":555,"version":0,"nonce":2,"sender":"NUVPACMnKFhpuHjsRjhUvXz1XhqfGZYVtY","sysfee":"10000000","netfee":"4488350","validuntilblock":1200,"attributes":[],"signers":[{"account":"0x95307cb9cc8c4578cef9f6845895eb7aa8be125e","scopes":"CalledByEntry"}],"script":"Ahjd9QUMFKqKz4WdT+QCs05nPyFWgheWpIjrDBReEr6oeuuVWIT2+c54RYzMuXwwlRPADAh0cmFuc2ZlcgwUJQWey0h406h1+RxRzt7TMNRXX95BYn1bUjg=","witnesses":[{"invocation":"DEAIcSUsAtRql4t+IEeo+p4+YI7bA6PG+1xxUkPIb2vNlaMl4PumjQVFT+bg2ldxCYa6zccoc4n0Gfryi82EhGpGDECR4fQDr4njo94mF6/GA+OH0Y5k735yGMEZHs96586BRp6f0AQxfmIPvLcS4Yero9p0zgVl9BDg3TxU5piRylR5DEAcjOT7JjEwNRnKgDDkXfh63Yc3MorMbdb2asTiDu0aexy5M5XcikA1jypJT4wkhxjp0rrgFZRSzeYhwV0Klz+yDECIopKxLd4p+hLHxFq07WffXd++sN0WIRWzvMJncCrJqSP8zz65r8TGFFzvZMdGelWKO7KhBOhIK6wryuWNlaDI","verification":"EwwhAhA6f33QFlWFl/eWDSfFFqQ5T9loueZRVetLAT5AQEBuDCECp7xV/oaE4BGXaNEEujB5W9zIZhnoZK3SYVZyPtGFzWIMIQKzYiv0AXvf4xfFiu1fTHU/IGt9uJYEb6fXdLvEv3+NwgwhA9kMB99j5pDOd5EuEKtRrMlEtmhgI3tgjE+PgwnnHuaZFAtBE43vrw=="}]}}`

 // getResultBlock1 returns data for block number 1 which is used by several tests.
 func getResultBlock1() *result.Block {
@ -64,14 +64,14 @@ func getResultBlock1() *result.Block {
 	if err != nil {
 		panic(err)
 	}
-	b2Hash, err := util.Uint256DecodeStringLE("45f62d72e37b074ecdc9f687222b0f91ec98d6d9af4429a2caa2e076a9196b0d")
+	b2Hash, err := util.Uint256DecodeStringLE("003abea54aa3c5edba7e33fb7ca96452cb65ff8cd36ce1cdfd412a6c4d3ea38a")
 	if err != nil {
 		panic(err)
 	}
 	return &result.Block{
 		Block: *b,
 		BlockMetadata: result.BlockMetadata{
-			Size:          1681,
+			Size:          1641,
 			NextBlockHash: &b2Hash,
 			Confirmations: 6,
 		},
@ -635,7 +635,7 @@ var rpcClientTestCases = map[string][]rpcClientTestCase{
 						Type:  smartcontract.Hash160Type,
 						Value: hash,
 					},
-				}, []transaction.Cosigner{{
+				}, []transaction.Signer{{
 					Account: util.Uint160{1, 2, 3},
 				}})
 			},
@ -662,7 +662,7 @@ var rpcClientTestCases = map[string][]rpcClientTestCase{
 				if err != nil {
 					panic(err)
 				}
-				return c.InvokeScript(script, []transaction.Cosigner{{
+				return c.InvokeScript(script, []transaction.Signer{{
 					Account: util.Uint160{1, 2, 3},
 				}})
 			},
--- a/pkg/rpc/client/wsclient.go
+++ b/pkg/rpc/client/wsclient.go
@ -255,12 +255,12 @@ func (c *WSClient) SubscribeForNewBlocks(primary *int) (string, error) {
 }

 // SubscribeForNewTransactions adds subscription for new transaction events to
-// this instance of client. It can be filtered by sender and/or cosigner, nil
+// this instance of client. It can be filtered by sender and/or signer, nil
 // value is treated as missing filter.
-func (c *WSClient) SubscribeForNewTransactions(sender *util.Uint160, cosigner *util.Uint160) (string, error) {
+func (c *WSClient) SubscribeForNewTransactions(sender *util.Uint160, signer *util.Uint160) (string, error) {
 	params := request.NewRawParams("transaction_added")
-	if sender != nil || cosigner != nil {
-		params.Values = append(params.Values, request.TxFilter{Sender: sender, Cosigner: cosigner})
+	if sender != nil || signer != nil {
+		params.Values = append(params.Values, request.TxFilter{Sender: sender, Signer: signer})
 	}
 	return c.performSubscription(params)
 }
--- a/pkg/rpc/client/wsclient_test.go
+++ b/pkg/rpc/client/wsclient_test.go
@ -119,7 +119,7 @@ func TestWSClientEvents(t *testing.T) {
 		`{"jsonrpc":"2.0","method":"transaction_executed","params":[{"txid":"0xe1cd5e57e721d2a2e05fb1f08721b12057b25ab1dd7fd0f33ee1639932fdfad7","trigger":"Application","vmstate":"HALT","gasconsumed":"22910000","stack":[],"notifications":[{"contract":"0x1b4357bff5a01bdf2a6581247cf9ed1e24629176","eventname":"contract call","state":{"type":"Array","value":[{"type":"ByteString","value":"dHJhbnNmZXI="},{"type":"Array","value":[{"type":"ByteString","value":"dpFiJB7t+XwkgWUq3xug9b9XQxs="},{"type":"ByteString","value":"MW6FEDkBnTnfwsN9bD/uGf1YCYc="},{"type":"Integer","value":"1000"}]}]}},{"contract":"0x1b4357bff5a01bdf2a6581247cf9ed1e24629176","eventname":"transfer","state":{"type":"Array","value":[{"type":"ByteString","value":"dpFiJB7t+XwkgWUq3xug9b9XQxs="},{"type":"ByteString","value":"MW6FEDkBnTnfwsN9bD/uGf1YCYc="},{"type":"Integer","value":"1000"}]}}]}]}`,
 		`{"jsonrpc":"2.0","method":"notification_from_execution","params":[{"contract":"0x1b4357bff5a01bdf2a6581247cf9ed1e24629176","eventname":"contract call","state":{"type":"Array","value":[{"type":"ByteString","value":"dHJhbnNmZXI="},{"type":"Array","value":[{"type":"ByteString","value":"dpFiJB7t+XwkgWUq3xug9b9XQxs="},{"type":"ByteString","value":"MW6FEDkBnTnfwsN9bD/uGf1YCYc="},{"type":"Integer","value":"1000"}]}]}}]}`,
 		`{"jsonrpc":"2.0","method":"transaction_executed","params":[{"txid":"0xf97a72b7722c109f909a8bc16c22368c5023d85828b09b127b237aace33cf099","trigger":"Application","vmstate":"HALT","gasconsumed":"6042610","stack":[],"notifications":[{"contract":"0xe65ff7b3a02d207b584a5c27057d4e9862ef01da","eventname":"contract call","state":{"type":"Array","value":[{"type":"ByteString","value":"dHJhbnNmZXI="},{"type":"Array","value":[{"type":"ByteString","value":"MW6FEDkBnTnfwsN9bD/uGf1YCYc="},{"type":"ByteString","value":"IHKCdK+vw29DoHHTKM+j5inZy7A="},{"type":"Integer","value":"123"}]}]}},{"contract":"0xe65ff7b3a02d207b584a5c27057d4e9862ef01da","eventname":"transfer","state":{"type":"Array","value":[{"type":"ByteString","value":"MW6FEDkBnTnfwsN9bD/uGf1YCYc="},{"type":"ByteString","value":"IHKCdK+vw29DoHHTKM+j5inZy7A="},{"type":"Integer","value":"123"}]}}]}]}`,
-		`{"jsonrpc":"2.0","method":"block_added","params":[{"hash":"0x2d312f6379ead13cf62634c703091b750e7903728df2a3cf5bd96ce80b84a849","version":0,"previousblockhash":"0xb8237d34c156cac6be7b01578decf8ac8c99a62f0b6f774d622aad7be0fe189d","merkleroot":"0xf89169e89361692b71e671f13c088e84c5325015c413e8f89e7ba38efdb41287","time":1592472500006,"index":6,"nextconsensus":"Nbb1qkwcwNSBs9pAnrVVrnFbWnbWBk91U2","witnesses":[{"invocation":"DEDblVguNGXWbUswDvBfVJzBt76BJyJ0Ga6siquyjioGn4Dbr6zy1IvcLl3xN5akcejRy9e+Mr1qvpe/gkLgtW4QDEDRwPISZagMFjE/plXTnZ/gEU0IbBAAe23U29zVWteUmzRsPxF/MdzXvdffR9W0edkj17AmkWpn+5rqzH9aCOpLDECEvjgxZaRoAHEDNzp1REllLcGzMwrwSjudtzfgRglQL3g1BKerDx6cGHH73medRVkL9QVm4KzSxlywVtvhwBMrDEBuPKvzg5TtakFW2jr/bfmy1bn2FiLARlOySwaGdKRV93ozA5lVEIAvHbBlJtT4/5H8jHjbncXXMrP3OUHqebZz","verification":"EwwhAhA6f33QFlWFl/eWDSfFFqQ5T9loueZRVetLAT5AQEBuDCECp7xV/oaE4BGXaNEEujB5W9zIZhnoZK3SYVZyPtGFzWIMIQKzYiv0AXvf4xfFiu1fTHU/IGt9uJYEb6fXdLvEv3+NwgwhA9kMB99j5pDOd5EuEKtRrMlEtmhgI3tgjE+PgwnnHuaZFAtBMHOzuw=="}],"consensusdata":{"primary":0,"nonce":"0000000000000457"},"tx":[{"hash":"0xf97a72b7722c109f909a8bc16c22368c5023d85828b09b127b237aace33cf099","size":265,"version":0,"nonce":9,"sender":"NQRLhCpAru9BjGsMwk67vdMwmzKMRgsnnN","sysfee":"0","netfee":"365210","validuntilblock":1200,"attributes":[],"cosigners":[{"account":"0x870958fd19ee3f6c7dc3c2df399d013910856e31","scopes":"CalledByEntry"}],"script":"AHsMFCBygnSvr8NvQ6Bx0yjPo+Yp2cuwDBQxboUQOQGdOd/Cw31sP+4Z/VgJhxPADAh0cmFuc2ZlcgwU2gHvYphOfQUnXEpYeyAtoLP3X+ZBYn1bUjg=","witnesses":[{"invocation":"DECwklSj3liZOJbktRtkVdUCu8U2LQlrU6Dv8NtMgd0xXbk5lXjc2p68xv6xtJXbJ4aoFMJZ9lkcNpGoeUCcaCet","verification":"DCECs2Ir9AF73+MXxYrtX0x1PyBrfbiWBG+n13S7xL9/jcILQQqQatQ="}]}]}]}`,
+		`{"jsonrpc":"2.0","method":"block_added","params":[{"size":1641,"nextblockhash":"0x003abea54aa3c5edba7e33fb7ca96452cb65ff8cd36ce1cdfd412a6c4d3ea38a","confirmations":6,"hash":"0xd9518e322440714b0564d6f84a9a39b527b5480e4e7f7932895777a4c8fa0a9e","version":0,"previousblockhash":"0xa496577895eb8c227bb866dc44f99f21c0cf06417ca8f2a877cc5d761a50dac0","merkleroot":"0x2b0f84636d814f3a952de145c8f4028f5664132f2719f5902e1884c9fba59806","time":1596101407001,"index":1,"nextconsensus":"NUVPACMnKFhpuHjsRjhUvXz1XhqfGZYVtY","witnesses":[{"invocation":"DEANAGtuw7+VLVNvmpESGL4+xqlKgBSIWmMBEtABi86ixft2Q7AcaOC89M+yKVIuTel9doVJcCvfx93CcQ63DZqCDEBtwUEkjuzP9h8ZTL0GEKfGr01pazmh8s2TswJge5sAGryYE/+kjw5NCLFmowhPU73qUYQ9jq1zMNMXF+Deqxp/DEDkytkkwJec5n4x2+l5zsZHT6QTXJsByZOWXaGPVJKK8CeDccZba7Mf4MdSkWqSt61xUtlgM2Iqhe/Iuokf/ZEXDEAOH72S12CuAxVu0XNGyj3cgMtad+Bghxvr16T9+ELaWkpR4ko26FdStYC2XiCkzanXTtAD1Id5rREsxfFeKb83","verification":"EwwhAhA6f33QFlWFl/eWDSfFFqQ5T9loueZRVetLAT5AQEBuDCECp7xV/oaE4BGXaNEEujB5W9zIZhnoZK3SYVZyPtGFzWIMIQKzYiv0AXvf4xfFiu1fTHU/IGt9uJYEb6fXdLvEv3+NwgwhA9kMB99j5pDOd5EuEKtRrMlEtmhgI3tgjE+PgwnnHuaZFAtBE43vrw=="}],"consensusdata":{"primary":0,"nonce":"0000000000000457"},"tx":[{"hash":"0x32f9bd3a2707475407c41bf5daacf9560e25ed74f6d85b3afb2ef72edb2325ba","size":555,"version":0,"nonce":2,"sender":"NUVPACMnKFhpuHjsRjhUvXz1XhqfGZYVtY","sysfee":"10000000","netfee":"4488350","validuntilblock":1200,"attributes":[],"signers":[{"account":"0x95307cb9cc8c4578cef9f6845895eb7aa8be125e","scopes":"CalledByEntry"}],"script":"Ahjd9QUMFKqKz4WdT+QCs05nPyFWgheWpIjrDBReEr6oeuuVWIT2+c54RYzMuXwwlRPADAh0cmFuc2ZlcgwUJQWey0h406h1+RxRzt7TMNRXX95BYn1bUjg=","witnesses":[{"invocation":"DEAIcSUsAtRql4t+IEeo+p4+YI7bA6PG+1xxUkPIb2vNlaMl4PumjQVFT+bg2ldxCYa6zccoc4n0Gfryi82EhGpGDECR4fQDr4njo94mF6/GA+OH0Y5k735yGMEZHs96586BRp6f0AQxfmIPvLcS4Yero9p0zgVl9BDg3TxU5piRylR5DEAcjOT7JjEwNRnKgDDkXfh63Yc3MorMbdb2asTiDu0aexy5M5XcikA1jypJT4wkhxjp0rrgFZRSzeYhwV0Klz+yDECIopKxLd4p+hLHxFq07WffXd++sN0WIRWzvMJncCrJqSP8zz65r8TGFFzvZMdGelWKO7KhBOhIK6wryuWNlaDI","verification":"EwwhAhA6f33QFlWFl/eWDSfFFqQ5T9loueZRVetLAT5AQEBuDCECp7xV/oaE4BGXaNEEujB5W9zIZhnoZK3SYVZyPtGFzWIMIQKzYiv0AXvf4xfFiu1fTHU/IGt9uJYEb6fXdLvEv3+NwgwhA9kMB99j5pDOd5EuEKtRrMlEtmhgI3tgjE+PgwnnHuaZFAtBE43vrw=="}]},{"hash":"0xd35d6386ec2f29b90839536f6af9466098d1665e951cdd0a20db6b4629b08369","size":559,"version":0,"nonce":3,"sender":"NUVPACMnKFhpuHjsRjhUvXz1XhqfGZYVtY","sysfee":"10000000","netfee":"4492350","validuntilblock":1200,"attributes":[],"signers":[{"account":"0x95307cb9cc8c4578cef9f6845895eb7aa8be125e","scopes":"CalledByEntry"}],"script":"AwDodkgXAAAADBSqis+FnU/kArNOZz8hVoIXlqSI6wwUXhK+qHrrlViE9vnOeEWMzLl8MJUTwAwIdHJhbnNmZXIMFLyvQdaEx9StbuDZnalwe50fDI5mQWJ9W1I4","witnesses":[{"invocation":"DECKUPl9d502XPI564EC2BroqpN274uV3n1z6kCBCmbS715lzmPbh24LESMsAP2TFohhdhm16aDfNsPi5tkB/FE4DEDzJFts9VYc1lIivGAZZSxACzAV/96Kn2WAaS3bDIlAJHCShsfz+Rn3NuvMyutujYM4vyEipAX9gkjcvFWGKRObDECkI883onhG9aYTxwQWDxsmofuiooRJOic/cJ1H8nqUEvMqATYKgdHaBOJBVYsKq9M9oUv/fj6JFbMDrcasvpiaDECEqkq2b50aEc1NGM9DBAsYLEeZHrM1BwX3a2tBOeeD/KLtmTga1IZogsZgpis2BOToZO6LuN9FJYcn+/iGcC5u","verification":"EwwhAhA6f33QFlWFl/eWDSfFFqQ5T9loueZRVetLAT5AQEBuDCECp7xV/oaE4BGXaNEEujB5W9zIZhnoZK3SYVZyPtGFzWIMIQKzYiv0AXvf4xfFiu1fTHU/IGt9uJYEb6fXdLvEv3+NwgwhA9kMB99j5pDOd5EuEKtRrMlEtmhgI3tgjE+PgwnnHuaZFAtBE43vrw=="}]}]}]}`,
 		`{"jsonrpc":"2.0","method":"event_missed","params":[]}`,
 	}
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
@ -204,13 +204,13 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 				filt, ok := param.Value.(request.TxFilter)
 				require.Equal(t, true, ok)
 				require.Equal(t, util.Uint160{1, 2, 3, 4, 5}, *filt.Sender)
-				require.Nil(t, filt.Cosigner)
+				require.Nil(t, filt.Signer)
 			},
 		},
-		{"transactions cosigner",
+		{"transactions signer",
 			func(t *testing.T, wsc *WSClient) {
-				cosigner := util.Uint160{0, 42}
-				_, err := wsc.SubscribeForNewTransactions(nil, &cosigner)
+				signer := util.Uint160{0, 42}
+				_, err := wsc.SubscribeForNewTransactions(nil, &signer)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *request.Params) {
@ -220,14 +220,14 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 				filt, ok := param.Value.(request.TxFilter)
 				require.Equal(t, true, ok)
 				require.Nil(t, filt.Sender)
-				require.Equal(t, util.Uint160{0, 42}, *filt.Cosigner)
+				require.Equal(t, util.Uint160{0, 42}, *filt.Signer)
 			},
 		},
-		{"transactions sender and cosigner",
+		{"transactions sender and signer",
 			func(t *testing.T, wsc *WSClient) {
 				sender := util.Uint160{1, 2, 3, 4, 5}
-				cosigner := util.Uint160{0, 42}
-				_, err := wsc.SubscribeForNewTransactions(&sender, &cosigner)
+				signer := util.Uint160{0, 42}
+				_, err := wsc.SubscribeForNewTransactions(&sender, &signer)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *request.Params) {
@ -237,7 +237,7 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 				filt, ok := param.Value.(request.TxFilter)
 				require.Equal(t, true, ok)
 				require.Equal(t, util.Uint160{1, 2, 3, 4, 5}, *filt.Sender)
-				require.Equal(t, util.Uint160{0, 42}, *filt.Cosigner)
+				require.Equal(t, util.Uint160{0, 42}, *filt.Signer)
 			},
 		},
 		{"notifications",
--- a/pkg/rpc/request/param.go
+++ b/pkg/rpc/request/param.go
@ -37,10 +37,10 @@ type (
 		Primary int `json:"primary"`
 	}
 	// TxFilter is a wrapper structure for transaction event filter. It
-	// allows to filter transactions by senders and cosigners.
+	// allows to filter transactions by senders and signers.
 	TxFilter struct {
 		Sender *util.Uint160 `json:"sender,omitempty"`
-		Cosigner *util.Uint160 `json:"cosigner,omitempty"`
+		Signer *util.Uint160 `json:"signer,omitempty"`
 	}
 	// NotificationFilter is a wrapper structure representing filter used for
 	// notifications generated during transaction execution. Notifications can
@ -67,7 +67,7 @@ const (
 	TxFilterT
 	NotificationFilterT
 	ExecutionFilterT
-	Cosigner
+	Signer
 )

 var errMissingParameter = errors.New("parameter is missing")
@ -207,24 +207,24 @@ func (p *Param) GetBytesBase64() ([]byte, error) {
 	return base64.StdEncoding.DecodeString(s)
 }

-// GetCosigner returns transaction.Cosigner value of the parameter.
-func (p Param) GetCosigner() (transaction.Cosigner, error) {
-	c, ok := p.Value.(transaction.Cosigner)
+// GetSigner returns transaction.Signer value of the parameter.
+func (p Param) GetSigner() (transaction.Signer, error) {
+	c, ok := p.Value.(transaction.Signer)
 	if !ok {
-		return transaction.Cosigner{}, errors.New("not a cosigner")
+		return transaction.Signer{}, errors.New("not a signer")
 	}
 	return c, nil
 }

-// GetCosigners returns a slice of transaction.Cosigner with global scope from
-// array of Uint160 or array of serialized transaction.Cosigner stored in the
+// GetSigners returns a slice of transaction.Signer with global scope from
+// array of Uint160 or array of serialized transaction.Signer stored in the
 // parameter.
-func (p Param) GetCosigners() ([]transaction.Cosigner, error) {
+func (p Param) GetSigners() ([]transaction.Signer, error) {
 	hashes, err := p.GetArray()
 	if err != nil {
 		return nil, err
 	}
-	cosigners := make([]transaction.Cosigner, len(hashes))
+	signers := make([]transaction.Signer, len(hashes))
 	// try to extract hashes first
 	for i, h := range hashes {
 		var u util.Uint160
@ -232,20 +232,20 @@ func (p Param) GetCosigners() ([]transaction.Cosigner, error) {
 		if err != nil {
 			break
 		}
-		cosigners[i] = transaction.Cosigner{
+		signers[i] = transaction.Signer{
 			Account: u,
 			Scopes:  transaction.Global,
 		}
 	}
 	if err != nil {
 		for i, h := range hashes {
-			cosigners[i], err = h.GetCosigner()
+			signers[i], err = h.GetSigner()
 			if err != nil {
 				return nil, err
 			}
 		}
 	}
-	return cosigners, nil
+	return signers, nil
 }

 // UnmarshalJSON implements json.Unmarshaler interface.
@ -261,7 +261,7 @@ func (p *Param) UnmarshalJSON(data []byte) error {
 		{TxFilterT, &TxFilter{}},
 		{NotificationFilterT, &NotificationFilter{}},
 		{ExecutionFilterT, &ExecutionFilter{}},
-		{Cosigner, &transaction.Cosigner{}},
+		{Signer, &transaction.Signer{}},
 		{ArrayT, &[]Param{}},
 	}

@ -296,7 +296,7 @@ func (p *Param) UnmarshalJSON(data []byte) error {
 				} else {
 					continue
 				}
-			case *transaction.Cosigner:
+			case *transaction.Signer:
 				p.Value = *val
 			case *[]Param:
 				p.Value = *val
--- a/pkg/rpc/request/param_test.go
+++ b/pkg/rpc/request/param_test.go
@ -18,8 +18,8 @@ func TestParam_UnmarshalJSON(t *testing.T) {
 	msg := `["str1", 123, null, ["str2", 3], [{"type": "String", "value": "jajaja"}],
                 {"primary": 1},
                 {"sender": "f84d6a337fbc3d3a201d41da99e86b479e7a2554"},
-                 {"cosigner": "f84d6a337fbc3d3a201d41da99e86b479e7a2554"},
-                 {"sender": "f84d6a337fbc3d3a201d41da99e86b479e7a2554", "cosigner": "f84d6a337fbc3d3a201d41da99e86b479e7a2554"},
+                 {"signer": "f84d6a337fbc3d3a201d41da99e86b479e7a2554"},
+                 {"sender": "f84d6a337fbc3d3a201d41da99e86b479e7a2554", "signer": "f84d6a337fbc3d3a201d41da99e86b479e7a2554"},
                 {"contract": "f84d6a337fbc3d3a201d41da99e86b479e7a2554"},
                 {"state": "HALT"},
                 {"account": "0xcadb3dc2faa3ef14a13b619c9a43124755aa2569"},
@ -78,11 +78,11 @@ func TestParam_UnmarshalJSON(t *testing.T) {
 		},
 		{
 			Type:  TxFilterT,
-			Value: TxFilter{Cosigner: &contr},
+			Value: TxFilter{Signer: &contr},
 		},
 		{
 			Type:  TxFilterT,
-			Value: TxFilter{Sender: &contr, Cosigner: &contr},
+			Value: TxFilter{Sender: &contr, Signer: &contr},
 		},
 		{
 			Type:  NotificationFilterT,
@ -93,8 +93,8 @@ func TestParam_UnmarshalJSON(t *testing.T) {
 			Value: ExecutionFilter{State: "HALT"},
 		},
 		{
-			Type: Cosigner,
-			Value: transaction.Cosigner{
+			Type: Signer,
+			Value: transaction.Signer{
 				Account: accountHash,
 				Scopes:  transaction.FeeOnly,
 			},
@ -103,8 +103,8 @@ func TestParam_UnmarshalJSON(t *testing.T) {
 			Type: ArrayT,
 			Value: []Param{
 				{
-					Type: Cosigner,
-					Value: transaction.Cosigner{
+					Type: Signer,
+					Value: transaction.Signer{
 						Account: accountHash,
 						Scopes:  transaction.Global,
 					},
@ -280,22 +280,22 @@ func TestParamGetBytesBase64(t *testing.T) {
 	require.NotNil(t, err)
 }

-func TestParamGetCosigner(t *testing.T) {
-	c := transaction.Cosigner{
+func TestParamGetSigner(t *testing.T) {
+	c := transaction.Signer{
 		Account: util.Uint160{1, 2, 3, 4},
 		Scopes:  transaction.Global,
 	}
-	p := Param{Type: Cosigner, Value: c}
-	actual, err := p.GetCosigner()
+	p := Param{Type: Signer, Value: c}
+	actual, err := p.GetSigner()
 	require.NoError(t, err)
 	require.Equal(t, c, actual)

-	p = Param{Type: Cosigner, Value: `{"account": "0xcadb3dc2faa3ef14a13b619c9a43124755aa2569", "scopes": 0}`}
-	_, err = p.GetCosigner()
+	p = Param{Type: Signer, Value: `{"account": "0xcadb3dc2faa3ef14a13b619c9a43124755aa2569", "scopes": 0}`}
+	_, err = p.GetSigner()
 	require.Error(t, err)
 }

-func TestParamGetCosigners(t *testing.T) {
+func TestParamGetSigners(t *testing.T) {
 	u1 := util.Uint160{1, 2, 3, 4}
 	u2 := util.Uint160{5, 6, 7, 8}
 	t.Run("from hashes", func(t *testing.T) {
@ -303,19 +303,19 @@ func TestParamGetCosigners(t *testing.T) {
 			{Type: StringT, Value: u1.StringLE()},
 			{Type: StringT, Value: u2.StringLE()},
 		}}
-		actual, err := p.GetCosigners()
+		actual, err := p.GetSigners()
 		require.NoError(t, err)
 		require.Equal(t, 2, len(actual))
 		require.True(t, u1.Equals(actual[0].Account))
 		require.True(t, u2.Equals(actual[1].Account))
 	})

-	t.Run("from cosigners", func(t *testing.T) {
-		c1 := transaction.Cosigner{
+	t.Run("from signers", func(t *testing.T) {
+		c1 := transaction.Signer{
 			Account: u1,
 			Scopes:  transaction.Global,
 		}
-		c2 := transaction.Cosigner{
+		c2 := transaction.Signer{
 			Account: u2,
 			Scopes:  transaction.CustomContracts,
 			AllowedContracts: []util.Uint160{
@ -324,10 +324,10 @@ func TestParamGetCosigners(t *testing.T) {
 			},
 		}
 		p := Param{ArrayT, []Param{
-			{Type: Cosigner, Value: c1},
-			{Type: Cosigner, Value: c2},
+			{Type: Signer, Value: c1},
+			{Type: Signer, Value: c2},
 		}}
-		actual, err := p.GetCosigners()
+		actual, err := p.GetSigners()
 		require.NoError(t, err)
 		require.Equal(t, 2, len(actual))
 		require.Equal(t, c1, actual[0])
@ -339,7 +339,7 @@ func TestParamGetCosigners(t *testing.T) {
 			{Type: StringT, Value: u1.StringLE()},
 			{Type: StringT, Value: "bla"},
 		}}
-		_, err := p.GetCosigners()
+		_, err := p.GetSigners()
 		require.Error(t, err)
 	})
 }
--- a/pkg/rpc/server/server.go
+++ b/pkg/rpc/server/server.go
@ -843,13 +843,16 @@ func (s *Server) invokeFunction(reqParams request.Params) (interface{}, *respons
 	tx := &transaction.Transaction{}
 	checkWitnessHashesIndex := len(reqParams)
 	if checkWitnessHashesIndex > 3 {
-		cosigners, err := reqParams[3].GetCosigners()
+		signers, err := reqParams[3].GetSigners()
 		if err != nil {
 			return nil, response.ErrInvalidParams
 		}
-		tx.Cosigners = cosigners
+		tx.Signers = signers
 		checkWitnessHashesIndex--
 	}
+	if len(tx.Signers) == 0 {
+		tx.Signers = []transaction.Signer{{Account: util.Uint160{}, Scopes: transaction.FeeOnly}}
+	}
 	script, err := request.CreateFunctionInvocationScript(scriptHash, reqParams[1:checkWitnessHashesIndex])
 	if err != nil {
 		return nil, response.NewInternalServerError("can't create invocation script", err)
@ -871,11 +874,14 @@ func (s *Server) invokescript(reqParams request.Params) (interface{}, *response.

 	tx := &transaction.Transaction{}
 	if len(reqParams) > 1 {
-		cosigners, err := reqParams[1].GetCosigners()
+		signers, err := reqParams[1].GetSigners()
 		if err != nil {
 			return nil, response.ErrInvalidParams
 		}
-		tx.Cosigners = cosigners
+		tx.Signers = signers
+	}
+	if len(tx.Signers) == 0 {
+		tx.Signers = []transaction.Signer{{Account: util.Uint160{}, Scopes: transaction.FeeOnly}}
 	}
 	tx.Script = script
 	return s.runScriptInVM(script, tx), nil
--- a/pkg/rpc/server/server_test.go
+++ b/pkg/rpc/server/server_test.go
@ -52,7 +52,7 @@ type rpcTestCase struct {
 }

 const testContractHash = "36c3b0c85d98607db00b711885ec3e411d9b1672"
-const deploymentTxHash = "ef4209bc06e1d8412995c645a8497d3e2c9a05ca52236de94297c6db9c3e94d0"
+const deploymentTxHash = "60a1fc8ceb7948d9933aec0cedd148441568575c40af7e0985cc366ed153d57e"

 var rpcTestCases = map[string][]rpcTestCase{
 	"getapplicationlog": {
@ -589,12 +589,12 @@ var rpcTestCases = map[string][]rpcTestCase{
 	"sendrawtransaction": {
 		{
 			name:   "positive",
-			params: `["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"]`,
+			params: `["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"]`,
 			result: func(e *executor) interface{} { return &result.RelayResult{} },
 			check: func(t *testing.T, e *executor, inv interface{}) {
 				res, ok := inv.(*result.RelayResult)
 				require.True(t, ok)
-				expectedHash, err := util.Uint256DecodeStringLE("72159b0cf1221110daad6e1df6ef4ff03012173b63c86910bd7134deb659c875")
+				expectedHash, err := util.Uint256DecodeStringLE("8b6e610a2205914411b26c4380594fa9a1e16961ff5896ed3b16831a151c6dd0")
 				require.NoError(t, err)
 				assert.Equal(t, expectedHash, res.Hash)
 			},
@ -744,7 +744,7 @@ func testRPCProtocol(t *testing.T, doRPCCall func(string, string, *testing.T) []
 			tx := transaction.New(testchain.Network(), []byte{byte(opcode.PUSH1)}, 0)
 			tx.Nonce = height + 1
 			tx.ValidUntilBlock = height + 10
-			tx.Sender = acc0.PrivateKey().GetScriptHash()
+			tx.Signers = []transaction.Signer{{Account: acc0.PrivateKey().GetScriptHash()}}
 			addNetworkFee(tx)
 			require.NoError(t, acc0.SignTx(tx))
 			return tx
@ -872,6 +872,7 @@ func testRPCProtocol(t *testing.T, doRPCCall func(string, string, *testing.T) []
 		}
 		for i := 0; i < 5; i++ {
 			tx := transaction.New(testchain.Network(), []byte{byte(opcode.PUSH1)}, 0)
+			tx.Signers = []transaction.Signer{{Account: util.Uint160{1, 2, 3}}}
 			assert.NoError(t, mp.Add(tx, &FeerStub{}))
 			expected = append(expected, tx.Hash())
 		}
@ -1000,7 +1001,7 @@ func checkNep5Balances(t *testing.T, e *executor, acc interface{}) {
 			},
 			{
 				Asset:       e.chain.UtilityTokenHash(),
-				Amount:      "915.79002700",
+				Amount:      "915.78962700",
 				LastUpdated: 6,
 			}},
 		Address: testchain.PrivateKeyByID(0).GetScriptHash().StringLE(),
@ -1101,7 +1102,7 @@ func checkNep5Transfers(t *testing.T, e *executor, acc interface{}) {
 		b, err := e.chain.GetBlock(h)
 		require.NoError(t, err)
 		for j := range b.Transactions {
-			if u.Equals(b.Transactions[j].Sender) {
+			if u.Equals(b.Transactions[j].Sender()) {
 				amount := b.Transactions[j].SystemFee + b.Transactions[j].NetworkFee
 				expected.Sent = append(expected.Sent, result.NEP5Transfer{
 					Timestamp: b.Timestamp,
--- a/pkg/rpc/server/subscription.go
+++ b/pkg/rpc/server/subscription.go
@ -58,18 +58,18 @@ func (f *feed) Matches(r *response.Notification) bool {
 	case response.TransactionEventID:
 		filt := f.filter.(request.TxFilter)
 		tx := r.Payload[0].(*transaction.Transaction)
-		senderOK := filt.Sender == nil || tx.Sender.Equals(*filt.Sender)
-		cosignerOK := true
-		if filt.Cosigner != nil {
-			cosignerOK = false
-			for i := range tx.Cosigners {
-				if tx.Cosigners[i].Account.Equals(*filt.Cosigner) {
-					cosignerOK = true
+		senderOK := filt.Sender == nil || tx.Sender().Equals(*filt.Sender)
+		signerOK := true
+		if filt.Signer != nil {
+			signerOK = false
+			for i := range tx.Signers {
+				if tx.Signers[i].Account.Equals(*filt.Signer) {
+					signerOK = true
 					break
 				}
 			}
 		}
-		return senderOK && cosignerOK
+		return senderOK && signerOK
 	case response.NotificationEventID:
 		filt := f.filter.(request.NotificationFilter)
 		notification := r.Payload[0].(result.NotificationEvent)
--- a/pkg/rpc/server/subscription_test.go
+++ b/pkg/rpc/server/subscription_test.go
@ -147,28 +147,28 @@ func TestFilteredSubscriptions(t *testing.T) {
 				require.Equal(t, address.Uint160ToString(goodSender), sender)
 			},
 		},
-		"tx matching cosigner": {
-			params: `["transaction_added", {"cosigner":"` + goodSender.StringLE() + `"}]`,
+		"tx matching signer": {
+			params: `["transaction_added", {"signer":"` + goodSender.StringLE() + `"}]`,
 			check: func(t *testing.T, resp *response.Notification) {
 				rmap := resp.Payload[0].(map[string]interface{})
 				require.Equal(t, response.TransactionEventID, resp.Event)
-				cosigners := rmap["cosigners"].([]interface{})
-				cosigner0 := cosigners[0].(map[string]interface{})
-				cosigner0acc := cosigner0["account"].(string)
-				require.Equal(t, "0x"+goodSender.StringLE(), cosigner0acc)
+				signers := rmap["signers"].([]interface{})
+				signer0 := signers[0].(map[string]interface{})
+				signer0acc := signer0["account"].(string)
+				require.Equal(t, "0x"+goodSender.StringLE(), signer0acc)
 			},
 		},
-		"tx matching sender and cosigner": {
-			params: `["transaction_added", {"sender":"` + goodSender.StringLE() + `", "cosigner":"` + goodSender.StringLE() + `"}]`,
+		"tx matching sender and signer": {
+			params: `["transaction_added", {"sender":"` + goodSender.StringLE() + `", "signer":"` + goodSender.StringLE() + `"}]`,
 			check: func(t *testing.T, resp *response.Notification) {
 				rmap := resp.Payload[0].(map[string]interface{})
 				require.Equal(t, response.TransactionEventID, resp.Event)
 				sender := rmap["sender"].(string)
 				require.Equal(t, address.Uint160ToString(goodSender), sender)
-				cosigners := rmap["cosigners"].([]interface{})
-				cosigner0 := cosigners[0].(map[string]interface{})
-				cosigner0acc := cosigner0["account"].(string)
-				require.Equal(t, "0x"+goodSender.StringLE(), cosigner0acc)
+				signers := rmap["signers"].([]interface{})
+				signer0 := signers[0].(map[string]interface{})
+				signer0acc := signer0["account"].(string)
+				require.Equal(t, "0x"+goodSender.StringLE(), signer0acc)
 			},
 		},
 		"notification matching": {
--- a/pkg/rpc/server/testdata/testblocks.acc
+++ b/pkg/rpc/server/testdata/testblocks.acc
--- a/pkg/smartcontract/context/context_test.go
+++ b/pkg/smartcontract/context/context_test.go
@ -169,6 +169,7 @@ func getContractTx() *transaction.Transaction {
 	tx := transaction.New(netmode.UnitTestNet, []byte{byte(opcode.PUSH1)}, 0)
 	tx.Attributes = make([]transaction.Attribute, 0)
 	tx.Scripts = make([]transaction.Witness, 0)
+	tx.Signers = []transaction.Signer{{Account: util.Uint160{1, 2, 3}}}
 	tx.Hash()
 	return tx
 }