diff --git a/cli/wallet/multisig.go b/cli/wallet/multisig.go
index 41d5b72e2..165f3079e 100644
--- a/cli/wallet/multisig.go
+++ b/cli/wallet/multisig.go
@@ -59,14 +59,16 @@ func signMultisig(ctx *cli.Context) error {
 	if !ok {
 		return cli.NewExitError("verifiable item is not a transaction", 1)
 	}
-	fmt.Fprintln(ctx.App.Writer, tx.Hash().StringLE())
 
 	priv := acc.PrivateKey()
 	sign := priv.Sign(tx.GetSignedPart())
 	if err := c.AddSignature(acc.Contract, priv.PublicKey(), sign); err != nil {
 		return cli.NewExitError(fmt.Errorf("can't add signature: %w", err), 1)
-	} else if err := writeParameterContext(c, ctx.String("out")); err != nil {
-		return cli.NewExitError(err, 1)
+	}
+	if out := ctx.String("out"); out != "" {
+		if err := writeParameterContext(c, out); err != nil {
+			return cli.NewExitError(err, 1)
+		}
 	}
 	if len(ctx.String(options.RPCEndpointFlag)) != 0 {
 		w, err := c.GetWitness(acc.Contract)
diff --git a/pkg/consensus/consensus_test.go b/pkg/consensus/consensus_test.go
index 6a34a1269..1d31b9089 100644
--- a/pkg/consensus/consensus_test.go
+++ b/pkg/consensus/consensus_test.go
@@ -9,6 +9,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"github.com/nspcc-dev/neo-go/pkg/core"
+	"github.com/nspcc-dev/neo-go/pkg/core/fee"
 	"github.com/nspcc-dev/neo-go/pkg/core/native"
 	"github.com/nspcc-dev/neo-go/pkg/core/storage"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
@@ -344,7 +345,7 @@ func signTx(t *testing.T, feePerByte int64, txs ...*transaction.Transaction) {
 	require.NoError(t, err)
 	for _, tx := range txs {
 		size := io.GetVarSize(tx)
-		netFee, sizeDelta := core.CalculateNetworkFee(rawScript)
+		netFee, sizeDelta := fee.Calculate(rawScript)
 		tx.NetworkFee += +netFee
 		size += sizeDelta
 		tx.NetworkFee += int64(size) * feePerByte
diff --git a/pkg/core/blockchain_test.go b/pkg/core/blockchain_test.go
index d3058776b..cfe5f0f11 100644
--- a/pkg/core/blockchain_test.go
+++ b/pkg/core/blockchain_test.go
@@ -9,6 +9,7 @@ import (
 
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
+	"github.com/nspcc-dev/neo-go/pkg/core/fee"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/interopnames"
 	"github.com/nspcc-dev/neo-go/pkg/core/mempool"
 	"github.com/nspcc-dev/neo-go/pkg/core/native"
@@ -300,7 +301,7 @@ func TestVerifyTx(t *testing.T) {
 		})
 		t.Run("AlmostEnoughNetworkFee", func(t *testing.T) {
 			tx := bc.newTestTx(h, testScript)
-			verificationNetFee, calcultedScriptSize := CalculateNetworkFee(accs[0].Contract.Script)
+			verificationNetFee, calcultedScriptSize := fee.Calculate(accs[0].Contract.Script)
 			expectedSize := io.GetVarSize(tx) + calcultedScriptSize
 			calculatedNetFee := verificationNetFee + int64(expectedSize)*bc.FeePerByte()
 			tx.NetworkFee = calculatedNetFee - 1
@@ -310,7 +311,7 @@ func TestVerifyTx(t *testing.T) {
 		})
 		t.Run("EnoughNetworkFee", func(t *testing.T) {
 			tx := bc.newTestTx(h, testScript)
-			verificationNetFee, calcultedScriptSize := CalculateNetworkFee(accs[0].Contract.Script)
+			verificationNetFee, calcultedScriptSize := fee.Calculate(accs[0].Contract.Script)
 			expectedSize := io.GetVarSize(tx) + calcultedScriptSize
 			calculatedNetFee := verificationNetFee + int64(expectedSize)*bc.FeePerByte()
 			tx.NetworkFee = calculatedNetFee
@@ -321,7 +322,7 @@ func TestVerifyTx(t *testing.T) {
 		t.Run("CalculateNetworkFee, signature script", func(t *testing.T) {
 			tx := bc.newTestTx(h, testScript)
 			expectedSize := io.GetVarSize(tx)
-			verificationNetFee, calculatedScriptSize := CalculateNetworkFee(accs[0].Contract.Script)
+			verificationNetFee, calculatedScriptSize := fee.Calculate(accs[0].Contract.Script)
 			expectedSize += calculatedScriptSize
 			expectedNetFee := verificationNetFee + int64(expectedSize)*bc.FeePerByte()
 			tx.NetworkFee = expectedNetFee
@@ -340,7 +341,7 @@ func TestVerifyTx(t *testing.T) {
 			require.NoError(t, multisigAcc.ConvertMultisig(1, pKeys))
 			multisigHash := hash.Hash160(multisigAcc.Contract.Script)
 			tx := bc.newTestTx(multisigHash, testScript)
-			verificationNetFee, calculatedScriptSize := CalculateNetworkFee(multisigAcc.Contract.Script)
+			verificationNetFee, calculatedScriptSize := fee.Calculate(multisigAcc.Contract.Script)
 			expectedSize := io.GetVarSize(tx) + calculatedScriptSize
 			expectedNetFee := verificationNetFee + int64(expectedSize)*bc.FeePerByte()
 			tx.NetworkFee = expectedNetFee
@@ -440,7 +441,7 @@ func TestVerifyTx(t *testing.T) {
 			rawScript := testchain.CommitteeVerificationScript()
 			require.NoError(t, err)
 			size := io.GetVarSize(tx)
-			netFee, sizeDelta := CalculateNetworkFee(rawScript)
+			netFee, sizeDelta := fee.Calculate(rawScript)
 			tx.NetworkFee += netFee
 			tx.NetworkFee += int64(size+sizeDelta) * bc.FeePerByte()
 			data := tx.GetSignedPart()
@@ -479,7 +480,7 @@ func TestVerifyTx(t *testing.T) {
 					Scopes:  transaction.None,
 				}}
 				size := io.GetVarSize(tx)
-				netFee, sizeDelta := CalculateNetworkFee(oracleScript)
+				netFee, sizeDelta := fee.Calculate(oracleScript)
 				tx.NetworkFee += netFee
 				tx.NetworkFee += int64(size+sizeDelta) * bc.FeePerByte()
 				return tx
diff --git a/pkg/core/fee/calculate.go b/pkg/core/fee/calculate.go
new file mode 100644
index 000000000..38ad41a22
--- /dev/null
+++ b/pkg/core/fee/calculate.go
@@ -0,0 +1,39 @@
+package fee
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/core/interop/crypto"
+	"github.com/nspcc-dev/neo-go/pkg/io"
+	"github.com/nspcc-dev/neo-go/pkg/vm"
+	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
+	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
+)
+
+// Calculate returns network fee for transaction
+func Calculate(script []byte) (int64, int) {
+	var (
+		netFee int64
+		size   int
+	)
+	if vm.IsSignatureContract(script) {
+		size += 67 + io.GetVarSize(script)
+		netFee += Opcode(opcode.PUSHDATA1, opcode.PUSHNULL, opcode.PUSHDATA1) + crypto.ECDSAVerifyPrice
+	} else if m, pubs, ok := vm.ParseMultiSigContract(script); ok {
+		n := len(pubs)
+		sizeInv := 66 * m
+		size += io.GetVarSize(sizeInv) + sizeInv + io.GetVarSize(script)
+		netFee += calculateMultisig(m) + calculateMultisig(n)
+		netFee += Opcode(opcode.PUSHNULL) + crypto.ECDSAVerifyPrice*int64(n)
+	} else {
+		// We can support more contract types in the future.
+	}
+	return netFee, size
+}
+
+func calculateMultisig(n int) int64 {
+	result := Opcode(opcode.PUSHDATA1) * int64(n)
+	bw := io.NewBufBinWriter()
+	emit.Int(bw.BinWriter, int64(n))
+	// it's a hack because prices of small PUSH* opcodes are equal
+	result += Opcode(opcode.Opcode(bw.Bytes()[0]))
+	return result
+}
diff --git a/pkg/core/opcode_price.go b/pkg/core/fee/opcode.go
similarity index 96%
rename from pkg/core/opcode_price.go
rename to pkg/core/fee/opcode.go
index 848826f07..27fa8b745 100644
--- a/pkg/core/opcode_price.go
+++ b/pkg/core/fee/opcode.go
@@ -1,11 +1,9 @@
-package core
+package fee
 
-import (
-	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
-)
+import "github.com/nspcc-dev/neo-go/pkg/vm/opcode"
 
-// opcodePrice returns the deployment prices of specified opcodes
-func opcodePrice(opcodes ...opcode.Opcode) int64 {
+// Opcode returns the deployment prices of specified opcodes.
+func Opcode(opcodes ...opcode.Opcode) int64 {
 	var result int64
 	for _, op := range opcodes {
 		result += prices[op]
diff --git a/pkg/core/gas_price.go b/pkg/core/gas_price.go
index 61657d379..e8641bc1a 100644
--- a/pkg/core/gas_price.go
+++ b/pkg/core/gas_price.go
@@ -1,6 +1,7 @@
 package core
 
 import (
+	"github.com/nspcc-dev/neo-go/pkg/core/fee"
 	"github.com/nspcc-dev/neo-go/pkg/vm"
 	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
 )
@@ -10,5 +11,5 @@ const StoragePrice = 100000
 
 // getPrice returns a price for executing op with the provided parameter.
 func getPrice(v *vm.VM, op opcode.Opcode, parameter []byte) int64 {
-	return opcodePrice(op)
+	return fee.Opcode(op)
 }
diff --git a/pkg/core/helper_test.go b/pkg/core/helper_test.go
index 5dfe24c90..d0bdf4477 100644
--- a/pkg/core/helper_test.go
+++ b/pkg/core/helper_test.go
@@ -14,6 +14,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/compiler"
 	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
+	"github.com/nspcc-dev/neo-go/pkg/core/fee"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/interopnames"
 	"github.com/nspcc-dev/neo-go/pkg/core/native"
 	"github.com/nspcc-dev/neo-go/pkg/core/storage"
@@ -407,7 +408,7 @@ func signTx(bc *Blockchain, txs ...*transaction.Transaction) error {
 	}
 	for _, tx := range txs {
 		size := io.GetVarSize(tx)
-		netFee, sizeDelta := CalculateNetworkFee(rawScript)
+		netFee, sizeDelta := fee.Calculate(rawScript)
 		tx.NetworkFee += netFee
 		size += sizeDelta
 		tx.NetworkFee += int64(size) * bc.FeePerByte()
@@ -422,13 +423,13 @@ func signTx(bc *Blockchain, txs ...*transaction.Transaction) error {
 
 func addNetworkFee(bc *Blockchain, tx *transaction.Transaction, sender *wallet.Account) error {
 	size := io.GetVarSize(tx)
-	netFee, sizeDelta := CalculateNetworkFee(sender.Contract.Script)
+	netFee, sizeDelta := fee.Calculate(sender.Contract.Script)
 	tx.NetworkFee += netFee
 	size += sizeDelta
 	for _, cosigner := range tx.Signers {
 		contract := bc.GetContractState(cosigner.Account)
 		if contract != nil {
-			netFee, sizeDelta = CalculateNetworkFee(contract.Script)
+			netFee, sizeDelta = fee.Calculate(contract.Script)
 			tx.NetworkFee += netFee
 			size += sizeDelta
 		}
diff --git a/pkg/core/native/oracle.go b/pkg/core/native/oracle.go
index 2a695bb9d..7ba340384 100644
--- a/pkg/core/native/oracle.go
+++ b/pkg/core/native/oracle.go
@@ -46,15 +46,19 @@ const (
 	oracleRequestPrice = 5000_0000
 )
 
-var oracleScript []byte
+var (
+	oracleInvokeScript []byte
+	oracleScript       []byte
+)
 
 func init() {
 	w := io.NewBufBinWriter()
 	emit.String(w.BinWriter, oracleName)
 	emit.Syscall(w.BinWriter, interopnames.NeoNativeCall)
-	h := hash.Hash160(w.Bytes())
+	oracleInvokeScript = w.Bytes()
+	h := hash.Hash160(oracleInvokeScript)
 
-	w.Reset()
+	w = io.NewBufBinWriter()
 	emit.Int(w.BinWriter, 0)
 	emit.Opcodes(w.BinWriter, opcode.NEWARRAY)
 	emit.String(w.BinWriter, "finish")
@@ -79,6 +83,13 @@ var (
 	ErrResponseNotFound = errors.New("oracle response not found")
 )
 
+// GetOracleInvokeScript returns oracle contract script.
+func GetOracleInvokeScript() []byte {
+	b := make([]byte, len(oracleInvokeScript))
+	copy(b, oracleInvokeScript)
+	return b
+}
+
 // GetOracleResponseScript returns script for transaction with oracle response.
 func GetOracleResponseScript() []byte {
 	b := make([]byte, len(oracleScript))
diff --git a/pkg/core/util.go b/pkg/core/util.go
index 7cfc479de..05c1ce495 100644
--- a/pkg/core/util.go
+++ b/pkg/core/util.go
@@ -7,7 +7,6 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
-	"github.com/nspcc-dev/neo-go/pkg/core/interop/crypto"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/interopnames"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
@@ -15,7 +14,6 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/io"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
 	"github.com/nspcc-dev/neo-go/pkg/util"
-	"github.com/nspcc-dev/neo-go/pkg/vm"
 	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
 	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
 )
@@ -129,33 +127,3 @@ func headerSliceReverse(dest []*block.Header) {
 		dest[i], dest[j] = dest[j], dest[i]
 	}
 }
-
-// CalculateNetworkFee returns network fee for transaction
-func CalculateNetworkFee(script []byte) (int64, int) {
-	var (
-		netFee int64
-		size   int
-	)
-	if vm.IsSignatureContract(script) {
-		size += 67 + io.GetVarSize(script)
-		netFee += opcodePrice(opcode.PUSHDATA1, opcode.PUSHNULL, opcode.PUSHDATA1) + crypto.ECDSAVerifyPrice
-	} else if m, pubs, ok := vm.ParseMultiSigContract(script); ok {
-		n := len(pubs)
-		sizeInv := 66 * m
-		size += io.GetVarSize(sizeInv) + sizeInv + io.GetVarSize(script)
-		netFee += calculateMultisigFee(m) + calculateMultisigFee(n)
-		netFee += opcodePrice(opcode.PUSHNULL) + crypto.ECDSAVerifyPrice*int64(n)
-	} else {
-		// We can support more contract types in the future.
-	}
-	return netFee, size
-}
-
-func calculateMultisigFee(n int) int64 {
-	result := opcodePrice(opcode.PUSHDATA1) * int64(n)
-	bw := io.NewBufBinWriter()
-	emit.Int(bw.BinWriter, int64(n))
-	// it's a hack because prices of small PUSH* opcodes are equal
-	result += opcodePrice(opcode.Opcode(bw.Bytes()[0]))
-	return result
-}
diff --git a/pkg/crypto/keys/publickey.go b/pkg/crypto/keys/publickey.go
index 0daa0431c..7eac8931f 100644
--- a/pkg/crypto/keys/publickey.go
+++ b/pkg/crypto/keys/publickey.go
@@ -333,7 +333,7 @@ func (p *PublicKey) Address() string {
 // Verify returns true if the signature is valid and corresponds
 // to the hash and public key.
 func (p *PublicKey) Verify(signature []byte, hash []byte) bool {
-	if p.X == nil || p.Y == nil {
+	if p.X == nil || p.Y == nil || len(signature) != 64 {
 		return false
 	}
 	rBytes := new(big.Int).SetBytes(signature[0:32])
diff --git a/pkg/crypto/keys/sign_verify_test.go b/pkg/crypto/keys/sign_verify_test.go
index 405a99c9d..7e0b8b217 100644
--- a/pkg/crypto/keys/sign_verify_test.go
+++ b/pkg/crypto/keys/sign_verify_test.go
@@ -52,6 +52,9 @@ func TestPubKeyVerify(t *testing.T) {
 		expected := true
 		assert.Equal(t, expected, result)
 
+		// Small signature, no panic.
+		assert.False(t, pubKey.Verify([]byte{1, 2, 3}, hashedData.BytesBE()))
+
 		pubKey = &PublicKey{}
 		assert.False(t, pubKey.Verify(signedData, hashedData.BytesBE()))
 	})
diff --git a/pkg/rpc/client/rpc.go b/pkg/rpc/client/rpc.go
index fb6175c54..61b734cb2 100644
--- a/pkg/rpc/client/rpc.go
+++ b/pkg/rpc/client/rpc.go
@@ -7,6 +7,7 @@ import (
 
 	"github.com/nspcc-dev/neo-go/pkg/core"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
+	"github.com/nspcc-dev/neo-go/pkg/core/fee"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
@@ -552,7 +553,7 @@ func (c *Client) AddNetworkFee(tx *transaction.Transaction, extraFee int64, accs
 			size += io.GetVarSize([]byte{}) * 2 // both scripts are empty
 			continue
 		}
-		netFee, sizeDelta := core.CalculateNetworkFee(accs[i].Contract.Script)
+		netFee, sizeDelta := fee.Calculate(accs[i].Contract.Script)
 		tx.NetworkFee += netFee
 		size += sizeDelta
 	}
diff --git a/pkg/rpc/server/client_test.go b/pkg/rpc/server/client_test.go
index 9ad40480d..11f845ead 100644
--- a/pkg/rpc/server/client_test.go
+++ b/pkg/rpc/server/client_test.go
@@ -6,7 +6,7 @@ import (
 	"testing"
 
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
-	"github.com/nspcc-dev/neo-go/pkg/core"
+	"github.com/nspcc-dev/neo-go/pkg/core/fee"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
@@ -105,7 +105,7 @@ func TestAddNetworkFee(t *testing.T) {
 		}}
 		require.NoError(t, c.AddNetworkFee(tx, 10, accs[0]))
 		require.NoError(t, accs[0].SignTx(tx))
-		cFee, _ := core.CalculateNetworkFee(accs[0].Contract.Script)
+		cFee, _ := fee.Calculate(accs[0].Contract.Script)
 		require.Equal(t, int64(io.GetVarSize(tx))*feePerByte+cFee+10, tx.NetworkFee)
 	})
 
@@ -129,8 +129,8 @@ func TestAddNetworkFee(t *testing.T) {
 		require.NoError(t, accs[0].SignTx(tx))
 		require.NoError(t, accs[1].SignTx(tx))
 		require.NoError(t, accs[2].SignTx(tx))
-		cFee, _ := core.CalculateNetworkFee(accs[0].Contract.Script)
-		cFeeM, _ := core.CalculateNetworkFee(accs[1].Contract.Script)
+		cFee, _ := fee.Calculate(accs[0].Contract.Script)
+		cFeeM, _ := fee.Calculate(accs[1].Contract.Script)
 		require.Equal(t, int64(io.GetVarSize(tx))*feePerByte+cFee+cFeeM+10, tx.NetworkFee)
 	})
 	t.Run("Contract", func(t *testing.T) {
diff --git a/pkg/rpc/server/server_test.go b/pkg/rpc/server/server_test.go
index 32d2ac9b3..e28863d85 100644
--- a/pkg/rpc/server/server_test.go
+++ b/pkg/rpc/server/server_test.go
@@ -19,6 +19,7 @@ import (
 	"github.com/gorilla/websocket"
 	"github.com/nspcc-dev/neo-go/pkg/core"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
+	"github.com/nspcc-dev/neo-go/pkg/core/fee"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
@@ -787,7 +788,7 @@ func testRPCProtocol(t *testing.T, doRPCCall func(string, string, *testing.T) []
 
 		addNetworkFee := func(tx *transaction.Transaction) {
 			size := io.GetVarSize(tx)
-			netFee, sizeDelta := core.CalculateNetworkFee(acc0.Contract.Script)
+			netFee, sizeDelta := fee.Calculate(acc0.Contract.Script)
 			tx.NetworkFee += netFee
 			size += sizeDelta
 			tx.NetworkFee += int64(size) * chain.FeePerByte()