diff --git a/pkg/consensus/payload_test.go b/pkg/consensus/payload_test.go
index 3101f6072..1eddab699 100644
--- a/pkg/consensus/payload_test.go
+++ b/pkg/consensus/payload_test.go
@@ -228,13 +228,13 @@ func randomRecoveryMessage(t *testing.T) *recoveryMessage {
 			{
 				ViewNumber:       0,
 				ValidatorIndex:   1,
-				Signature:        [64]byte{1, 2, 3},
+				Signature:        [keys.SignatureLen]byte{1, 2, 3},
 				InvocationScript: random.Bytes(20),
 			},
 			{
 				ViewNumber:       0,
 				ValidatorIndex:   2,
-				Signature:        [64]byte{11, 3, 4, 98},
+				Signature:        [keys.SignatureLen]byte{11, 3, 4, 98},
 				InvocationScript: random.Bytes(10),
 			},
 		},
diff --git a/pkg/core/blockchain_neotest_test.go b/pkg/core/blockchain_neotest_test.go
index ffe9f23ba..043939c5a 100644
--- a/pkg/core/blockchain_neotest_test.go
+++ b/pkg/core/blockchain_neotest_test.go
@@ -559,9 +559,9 @@ func TestBlockchain_VerifyHashAgainstScript(t *testing.T) {
 		require.True(t, errors.Is(err, core.ErrVerificationFailed))
 	})
 	t.Run("BadResult", func(t *testing.T) {
-		verif := make([]byte, 66)
+		verif := make([]byte, keys.SignatureLen+2)
 		verif[0] = byte(opcode.PUSHDATA1)
-		verif[1] = 64
+		verif[1] = keys.SignatureLen
 		w := &transaction.Witness{
 			InvocationScript:   []byte{byte(opcode.NOP)},
 			VerificationScript: verif,
@@ -1634,7 +1634,7 @@ func TestBlockchain_VerifyTx(t *testing.T) {
 						VerificationScript: rawScript,
 					},
 					{
-						InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, notary.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), tx)...),
+						InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, notary.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), tx)...),
 					},
 				}
 				return tx
@@ -1679,7 +1679,7 @@ func TestBlockchain_VerifyTx(t *testing.T) {
 							VerificationScript: committee.Script(),
 						},
 						{
-							InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, notary.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), tx)...),
+							InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, notary.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), tx)...),
 						},
 					}
 					require.Error(t, bc.VerifyTx(tx))
@@ -1698,7 +1698,7 @@ func TestBlockchain_VerifyTx(t *testing.T) {
 					}
 					tx.Scripts = []transaction.Witness{
 						{
-							InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, notary.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), tx)...),
+							InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, notary.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), tx)...),
 						},
 						{
 							InvocationScript:   committee.SignHashable(uint32(netmode.UnitTestNet), tx),
@@ -1725,7 +1725,7 @@ func TestBlockchain_VerifyTx(t *testing.T) {
 							VerificationScript: committee.Script(),
 						},
 						{
-							InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, notary.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), tx)...),
+							InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, notary.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), tx)...),
 						},
 					}
 					require.Error(t, bc.VerifyTx(tx))
@@ -1766,7 +1766,7 @@ func TestBlockchain_VerifyTx(t *testing.T) {
 							VerificationScript: committee.Script(),
 						},
 						{
-							InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, acc.SignHashable(uint32(netmode.UnitTestNet), tx)...),
+							InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, acc.SignHashable(uint32(netmode.UnitTestNet), tx)...),
 						},
 					}
 					require.Error(t, bc.VerifyTx(tx))
@@ -1781,7 +1781,7 @@ func TestBlockchain_VerifyTx(t *testing.T) {
 					}
 					tx.Scripts = []transaction.Witness{
 						{
-							InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, notary.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), tx)...),
+							InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, notary.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), tx)...),
 						},
 					}
 					require.Error(t, bc.VerifyTx(tx))
@@ -1831,7 +1831,7 @@ func TestBlockchain_VerifyTx(t *testing.T) {
 				nativeprices.NotaryVerificationPrice*bc.GetBaseExecFee() // Notary witness verification price
 			tx.Scripts = []transaction.Witness{
 				{
-					InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...),
+					InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...),
 					VerificationScript: []byte{},
 				},
 				{
@@ -1858,7 +1858,7 @@ func TestBlockchain_VerifyTx(t *testing.T) {
 			tx.NetworkFee-- // to check that NetworkFee was set correctly in getPartiallyFilledTx
 			tx.Scripts = []transaction.Witness{
 				{
-					InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...),
+					InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...),
 					VerificationScript: []byte{},
 				},
 				{
diff --git a/pkg/core/native/native_test/gas_test.go b/pkg/core/native/native_test/gas_test.go
index a478b13a9..dd270ade2 100644
--- a/pkg/core/native/native_test/gas_test.go
+++ b/pkg/core/native/native_test/gas_test.go
@@ -120,7 +120,7 @@ func TestGAS_RewardWithP2PSigExtensionsEnabled(t *testing.T) {
 	}
 	tx.Scripts = []transaction.Witness{
 		{
-			InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, notaryNodes[0].SignHashable(uint32(e.Chain.GetConfig().Magic), tx)...),
+			InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, notaryNodes[0].SignHashable(uint32(e.Chain.GetConfig().Magic), tx)...),
 		},
 		{
 			InvocationScript:   e.Committee.SignHashable(uint32(e.Chain.GetConfig().Magic), tx),
diff --git a/pkg/core/native/native_test/management_test.go b/pkg/core/native/native_test/management_test.go
index dd64aeed5..37699f59d 100644
--- a/pkg/core/native/native_test/management_test.go
+++ b/pkg/core/native/native_test/management_test.go
@@ -126,7 +126,7 @@ func TestManagement_ContractDeploy(t *testing.T) {
 		require.NoError(t, err)
 
 		badManifest := cs1.Manifest
-		badManifest.Groups = []manifest.Group{{PublicKey: pkey.PublicKey(), Signature: make([]byte, 64)}}
+		badManifest.Groups = []manifest.Group{{PublicKey: pkey.PublicKey(), Signature: make([]byte, keys.SignatureLen)}}
 		manifB, err := json.Marshal(&badManifest)
 		require.NoError(t, err)
 
@@ -432,7 +432,7 @@ func TestManagement_ContractUpdate(t *testing.T) {
 		require.NoError(t, err)
 
 		var badManifest = cs1.Manifest
-		badManifest.Groups = []manifest.Group{{PublicKey: pkey.PublicKey(), Signature: make([]byte, 64)}}
+		badManifest.Groups = []manifest.Group{{PublicKey: pkey.PublicKey(), Signature: make([]byte, keys.SignatureLen)}}
 		manifB, err := json.Marshal(badManifest)
 		require.NoError(t, err)
 
diff --git a/pkg/core/native/native_test/notary_test.go b/pkg/core/native/native_test/notary_test.go
index 40339ebe5..a7f020f61 100644
--- a/pkg/core/native/native_test/notary_test.go
+++ b/pkg/core/native/native_test/notary_test.go
@@ -221,7 +221,7 @@ func TestNotary_NotaryNodesReward(t *testing.T) {
 		}
 		tx.Scripts = []transaction.Witness{
 			{
-				InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, notaryNodes[0].SignHashable(uint32(e.Chain.GetConfig().Magic), tx)...),
+				InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, notaryNodes[0].SignHashable(uint32(e.Chain.GetConfig().Magic), tx)...),
 			},
 			{
 				InvocationScript:   e.Committee.SignHashable(uint32(e.Chain.GetConfig().Magic), tx),
diff --git a/pkg/crypto/hash/hash.go b/pkg/crypto/hash/hash.go
index 9df09c66f..a997a3514 100644
--- a/pkg/crypto/hash/hash.go
+++ b/pkg/crypto/hash/hash.go
@@ -17,7 +17,7 @@ type Hashable interface {
 }
 
 func getSignedData(net uint32, hh Hashable) []byte {
-	var b = make([]byte, 4+32)
+	var b = make([]byte, 4+util.Uint256Size)
 	binary.LittleEndian.PutUint32(b, net)
 	h := hh.Hash()
 	copy(b[4:], h[:])
diff --git a/pkg/neotest/signer.go b/pkg/neotest/signer.go
index df529e607..333144434 100644
--- a/pkg/neotest/signer.go
+++ b/pkg/neotest/signer.go
@@ -9,6 +9,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"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"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/nspcc-dev/neo-go/pkg/vm"
 	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
@@ -73,7 +74,7 @@ func (s *signer) ScriptHash() util.Uint160 {
 
 // SignHashable implements Signer interface.
 func (s *signer) SignHashable(magic uint32, item hash.Hashable) []byte {
-	return append([]byte{byte(opcode.PUSHDATA1), 64},
+	return append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen},
 		(*wallet.Account)(s).SignHashable(netmode.Magic(magic), item)...)
 }
 
@@ -131,7 +132,7 @@ func (m multiSigner) SignHashable(magic uint32, item hash.Hashable) []byte {
 	var script []byte
 	for i := 0; i < m.m; i++ {
 		sign := m.accounts[i].SignHashable(netmode.Magic(magic), item)
-		script = append(script, byte(opcode.PUSHDATA1), 64)
+		script = append(script, byte(opcode.PUSHDATA1), keys.SignatureLen)
 		script = append(script, sign...)
 	}
 	return script
diff --git a/pkg/network/payload/notary_request.go b/pkg/network/payload/notary_request.go
index 8c68efe8a..afc8f813b 100644
--- a/pkg/network/payload/notary_request.go
+++ b/pkg/network/payload/notary_request.go
@@ -6,6 +6,7 @@ import (
 
 	"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"
 	"github.com/nspcc-dev/neo-go/pkg/io"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
@@ -110,7 +111,7 @@ func (r *P2PNotaryRequest) isValid() error {
 	}
 	if len(r.FallbackTransaction.Scripts[0].InvocationScript) != 66 ||
 		len(r.FallbackTransaction.Scripts[0].VerificationScript) != 0 ||
-		!bytes.HasPrefix(r.FallbackTransaction.Scripts[0].InvocationScript, []byte{byte(opcode.PUSHDATA1), 64}) {
+		!bytes.HasPrefix(r.FallbackTransaction.Scripts[0].InvocationScript, []byte{byte(opcode.PUSHDATA1), keys.SignatureLen}) {
 		return errors.New("fallback transaction has invalid dummy Notary witness")
 	}
 	if !r.FallbackTransaction.HasAttribute(transaction.NotValidBeforeT) {
diff --git a/pkg/network/payload/notary_request_test.go b/pkg/network/payload/notary_request_test.go
index 8e0bc6ea0..41eb073f8 100644
--- a/pkg/network/payload/notary_request_test.go
+++ b/pkg/network/payload/notary_request_test.go
@@ -5,6 +5,7 @@ import (
 
 	"github.com/nspcc-dev/neo-go/internal/random"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
 	"github.com/stretchr/testify/require"
@@ -45,21 +46,21 @@ func TestNotaryRequestIsValid(t *testing.T) {
 			MainTransaction: mainTx,
 			FallbackTransaction: &transaction.Transaction{
 				Signers: []transaction.Signer{{Account: random.Uint160()}, {Account: random.Uint160()}},
-				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 65}, make([]byte, 64)...)}, {}},
+				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 65}, make([]byte, keys.SignatureLen)...)}, {}},
 			},
 		},
 		"fallback tx: invalid dummy Notary witness (non-empty verification script))": {
 			MainTransaction: mainTx,
 			FallbackTransaction: &transaction.Transaction{
 				Signers: []transaction.Signer{{Account: random.Uint160()}, {Account: random.Uint160()}},
-				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...), VerificationScript: make([]byte, 1)}, {}},
+				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...), VerificationScript: make([]byte, 1)}, {}},
 			},
 		},
 		"fallback tx: missing NotValidBefore attribute": {
 			MainTransaction: mainTx,
 			FallbackTransaction: &transaction.Transaction{
 				Signers: []transaction.Signer{{Account: random.Uint160()}, {Account: random.Uint160()}},
-				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...), VerificationScript: make([]byte, 0)}, {}},
+				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...), VerificationScript: make([]byte, 0)}, {}},
 			},
 		},
 		"fallback tx: invalid number of Conflicts attributes": {
@@ -67,7 +68,7 @@ func TestNotaryRequestIsValid(t *testing.T) {
 			FallbackTransaction: &transaction.Transaction{
 				Attributes: []transaction.Attribute{{Type: transaction.NotValidBeforeT, Value: &transaction.NotValidBefore{Height: 123}}},
 				Signers:    []transaction.Signer{{Account: random.Uint160()}, {Account: random.Uint160()}},
-				Scripts:    []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...), VerificationScript: make([]byte, 0)}, {}},
+				Scripts:    []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...), VerificationScript: make([]byte, 0)}, {}},
 			},
 		},
 		"fallback tx: does not conflicts with main tx": {
@@ -78,7 +79,7 @@ func TestNotaryRequestIsValid(t *testing.T) {
 					{Type: transaction.ConflictsT, Value: &transaction.Conflicts{Hash: util.Uint256{}}},
 				},
 				Signers: []transaction.Signer{{Account: random.Uint160()}, {Account: random.Uint160()}},
-				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...), VerificationScript: make([]byte, 0)}, {}},
+				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...), VerificationScript: make([]byte, 0)}, {}},
 			},
 		},
 		"fallback tx: missing NotaryAssisted attribute": {
@@ -89,7 +90,7 @@ func TestNotaryRequestIsValid(t *testing.T) {
 					{Type: transaction.ConflictsT, Value: &transaction.Conflicts{Hash: mainTx.Hash()}},
 				},
 				Signers: []transaction.Signer{{Account: random.Uint160()}, {Account: random.Uint160()}},
-				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...), VerificationScript: make([]byte, 0)}, {}},
+				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...), VerificationScript: make([]byte, 0)}, {}},
 			},
 		},
 		"fallback tx: non-zero NKeys": {
@@ -101,7 +102,7 @@ func TestNotaryRequestIsValid(t *testing.T) {
 					{Type: transaction.NotaryAssistedT, Value: &transaction.NotaryAssisted{NKeys: 1}},
 				},
 				Signers: []transaction.Signer{{Account: random.Uint160()}, {Account: random.Uint160()}},
-				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...), VerificationScript: make([]byte, 0)}, {}},
+				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...), VerificationScript: make([]byte, 0)}, {}},
 			},
 		},
 		"fallback tx: ValidUntilBlock mismatch": {
@@ -114,7 +115,7 @@ func TestNotaryRequestIsValid(t *testing.T) {
 					{Type: transaction.NotaryAssistedT, Value: &transaction.NotaryAssisted{NKeys: 0}},
 				},
 				Signers: []transaction.Signer{{Account: random.Uint160()}, {Account: random.Uint160()}},
-				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...), VerificationScript: make([]byte, 0)}, {}},
+				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...), VerificationScript: make([]byte, 0)}, {}},
 			},
 		},
 	}
@@ -134,7 +135,7 @@ func TestNotaryRequestIsValid(t *testing.T) {
 					{Type: transaction.NotaryAssistedT, Value: &transaction.NotaryAssisted{NKeys: 0}},
 				},
 				Signers: []transaction.Signer{{Account: random.Uint160()}, {Account: random.Uint160()}},
-				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...), VerificationScript: make([]byte, 0)}, {}},
+				Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...), VerificationScript: make([]byte, 0)}, {}},
 			},
 		}
 		require.NoError(t, p.isValid())
@@ -164,7 +165,7 @@ func TestNotaryRequestBytesFromBytes(t *testing.T) {
 		},
 		Signers: []transaction.Signer{{Account: util.Uint160{1, 4, 7}}, {Account: util.Uint160{9, 8, 7}}},
 		Scripts: []transaction.Witness{
-			{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...), VerificationScript: make([]byte, 0)},
+			{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...), VerificationScript: make([]byte, 0)},
 			{InvocationScript: []byte{1, 2, 3}, VerificationScript: []byte{1, 2, 3}}},
 	}
 	_ = fallbackTx.Hash()
diff --git a/pkg/network/server_test.go b/pkg/network/server_test.go
index 750878e9f..578e82f7e 100644
--- a/pkg/network/server_test.go
+++ b/pkg/network/server_test.go
@@ -19,6 +19,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
 	"github.com/nspcc-dev/neo-go/pkg/core/mpt"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/network/capability"
 	"github.com/nspcc-dev/neo-go/pkg/network/payload"
 	"github.com/nspcc-dev/neo-go/pkg/util"
@@ -545,7 +546,7 @@ func TestGetData(t *testing.T) {
 				{Type: transaction.NotaryAssistedT, Value: &transaction.NotaryAssisted{NKeys: 0}},
 			},
 			Signers: []transaction.Signer{{Account: random.Uint160()}, {Account: random.Uint160()}},
-			Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...), VerificationScript: make([]byte, 0)}, {InvocationScript: []byte{}, VerificationScript: []byte{}}},
+			Scripts: []transaction.Witness{{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...), VerificationScript: make([]byte, 0)}, {InvocationScript: []byte{}, VerificationScript: []byte{}}},
 		}
 		fallbackTx.Size()
 		fallbackTx.Hash()
diff --git a/pkg/rpcclient/notary/actor.go b/pkg/rpcclient/notary/actor.go
index 06c9ef958..c99a4e7af 100644
--- a/pkg/rpcclient/notary/actor.go
+++ b/pkg/rpcclient/notary/actor.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
 	"github.com/nspcc-dev/neo-go/pkg/network/payload"
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient/actor"
@@ -278,7 +279,7 @@ func (a *Actor) SendRequest(mainTx *transaction.Transaction, fbTx *transaction.T
 	if err != nil {
 		return mainHash, fbHash, vub, err
 	}
-	fbTx.Scripts[0].InvocationScript = append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...) // Must be present.
+	fbTx.Scripts[0].InvocationScript = append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...) // Must be present.
 	return a.SendRequestExactly(mainTx, fbTx)
 }
 
@@ -300,7 +301,7 @@ func (a *Actor) SendRequestExactly(mainTx *transaction.Transaction, fbTx *transa
 		FallbackTransaction: fbTx,
 	}
 	req.Witness = transaction.Witness{
-		InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, a.sender.SignHashable(a.GetNetwork(), req)...),
+		InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, a.sender.SignHashable(a.GetNetwork(), req)...),
 		VerificationScript: a.sender.GetVerificationScript(),
 	}
 	actualHash, err := a.rpc.SubmitP2PNotaryRequest(req)
diff --git a/pkg/rpcclient/rpc.go b/pkg/rpcclient/rpc.go
index 9e2c86264..112689bea 100644
--- a/pkg/rpcclient/rpc.go
+++ b/pkg/rpcclient/rpc.go
@@ -893,7 +893,7 @@ func (c *Client) SignAndPushP2PNotaryRequest(mainTx *transaction.Transaction, fa
 
 	fallbackTx.Scripts = []transaction.Witness{
 		{
-			InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...),
+			InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...),
 			VerificationScript: []byte{},
 		},
 		{
@@ -919,7 +919,7 @@ func (c *Client) SignAndPushP2PNotaryRequest(mainTx *transaction.Transaction, fa
 		FallbackTransaction: fallbackTx,
 	}
 	req.Witness = transaction.Witness{
-		InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, acc.SignHashable(m, req)...),
+		InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, acc.SignHashable(m, req)...),
 		VerificationScript: acc.GetVerificationScript(),
 	}
 	actualHash, err := c.SubmitP2PNotaryRequest(req)
diff --git a/pkg/services/notary/core_test.go b/pkg/services/notary/core_test.go
index 844aeab92..fe1c9e156 100644
--- a/pkg/services/notary/core_test.go
+++ b/pkg/services/notary/core_test.go
@@ -199,7 +199,7 @@ func TestNotary(t *testing.T) {
 		}
 		fallback.Scripts = []transaction.Witness{
 			{
-				InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...),
+				InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...),
 				VerificationScript: []byte{},
 			},
 		}
@@ -261,7 +261,7 @@ func TestNotary(t *testing.T) {
 				for j := range main.Scripts {
 					main.Scripts[j].VerificationScript = verificationScripts[j]
 					if i == j {
-						main.Scripts[j].InvocationScript = append([]byte{byte(opcode.PUSHDATA1), 64}, acc.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), main)...)
+						main.Scripts[j].InvocationScript = append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, acc.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), main)...)
 					}
 				}
 				main.Scripts = append(main.Scripts, transaction.Witness{}) // empty Notary witness
@@ -310,7 +310,7 @@ func TestNotary(t *testing.T) {
 				require.NoError(t, err)
 			}
 			require.Equal(t, transaction.Witness{
-				InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, acc1.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), requests[0].MainTransaction)...),
+				InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, acc1.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), requests[0].MainTransaction)...),
 				VerificationScript: []byte{},
 			}, completedTx.Scripts[len(completedTx.Scripts)-1])
 		} else {
@@ -325,7 +325,7 @@ func TestNotary(t *testing.T) {
 				require.Equal(t, 2, len(completedTx.Signers))
 				require.Equal(t, 2, len(completedTx.Scripts))
 				require.Equal(t, transaction.Witness{
-					InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, acc1.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), req.FallbackTransaction)...),
+					InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, acc1.PrivateKey().SignHashable(uint32(netmode.UnitTestNet), req.FallbackTransaction)...),
 					VerificationScript: []byte{},
 				}, completedTx.Scripts[0])
 
diff --git a/pkg/services/notary/notary.go b/pkg/services/notary/notary.go
index c626fb854..dc3d93a85 100644
--- a/pkg/services/notary/notary.go
+++ b/pkg/services/notary/notary.go
@@ -392,7 +392,7 @@ func (n *Notary) PostPersist() {
 // finalize adds missing Notary witnesses to the transaction (main or fallback) and pushes it to the network.
 func (n *Notary) finalize(acc *wallet.Account, tx *transaction.Transaction, h util.Uint256) error {
 	notaryWitness := transaction.Witness{
-		InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, acc.SignHashable(n.Network, tx)...),
+		InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, acc.SignHashable(n.Network, tx)...),
 		VerificationScript: []byte{},
 	}
 	for i, signer := range tx.Signers {
@@ -515,7 +515,7 @@ func (n *Notary) verifyIncompleteWitnesses(tx *transaction.Transaction, nKeysExp
 		}
 		// Each verification script is allowed to have either one signature or zero signatures. If signature is provided, then need to verify it.
 		if len(w.InvocationScript) != 0 {
-			if len(w.InvocationScript) != 66 || !bytes.HasPrefix(w.InvocationScript, []byte{byte(opcode.PUSHDATA1), 64}) {
+			if len(w.InvocationScript) != 66 || !bytes.HasPrefix(w.InvocationScript, []byte{byte(opcode.PUSHDATA1), keys.SignatureLen}) {
 				return nil, fmt.Errorf("witness #%d: invocation script should have length = 66 and be of the form [PUSHDATA1, 64, signatureBytes...]", i)
 			}
 		}
diff --git a/pkg/services/notary/notary_test.go b/pkg/services/notary/notary_test.go
index d8375e0d7..d3d173e99 100644
--- a/pkg/services/notary/notary_test.go
+++ b/pkg/services/notary/notary_test.go
@@ -51,7 +51,7 @@ func TestVerifyIncompleteRequest(t *testing.T) {
 	notaryContractHash := util.Uint160{1, 2, 3}
 	bc.NotaryContractScriptHash = notaryContractHash
 	_, ntr, _ := getTestNotary(t, bc, "./testdata/notary1.json", "one")
-	sig := append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...) // we're not interested in signature correctness
+	sig := append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...) // we're not interested in signature correctness
 	acc1, _ := keys.NewPrivateKey()
 	acc2, _ := keys.NewPrivateKey()
 	acc3, _ := keys.NewPrivateKey()
diff --git a/pkg/services/rpcsrv/client_test.go b/pkg/services/rpcsrv/client_test.go
index 247506d5b..aaf4b31f1 100644
--- a/pkg/services/rpcsrv/client_test.go
+++ b/pkg/services/rpcsrv/client_test.go
@@ -1089,7 +1089,7 @@ func TestSignAndPushP2PNotaryRequest(t *testing.T) {
 		err = ntr.Decrypt(notaryPass, w.Scrypt)
 		require.NoError(t, err)
 		req.FallbackTransaction.Scripts[0] = transaction.Witness{
-			InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, ntr.PrivateKey().SignHashable(uint32(testchain.Network()), req.FallbackTransaction)...),
+			InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, ntr.PrivateKey().SignHashable(uint32(testchain.Network()), req.FallbackTransaction)...),
 			VerificationScript: []byte{},
 		}
 		b := testchain.NewBlock(t, chain, 1, 0, req.FallbackTransaction)
diff --git a/pkg/services/rpcsrv/server_test.go b/pkg/services/rpcsrv/server_test.go
index e0e2ee86a..93f015121 100644
--- a/pkg/services/rpcsrv/server_test.go
+++ b/pkg/services/rpcsrv/server_test.go
@@ -1782,7 +1782,7 @@ func TestSubmitNotaryRequest(t *testing.T) {
 			},
 			Signers: []transaction.Signer{{Account: util.Uint160{1, 4, 7}}, {Account: util.Uint160{9, 8, 7}}},
 			Scripts: []transaction.Witness{
-				{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...), VerificationScript: make([]byte, 0)},
+				{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...), VerificationScript: make([]byte, 0)},
 				{InvocationScript: []byte{1, 2, 3}, VerificationScript: []byte{1, 2, 3}}},
 		}
 		p := &payload.P2PNotaryRequest{
@@ -1833,12 +1833,12 @@ func createValidNotaryRequest(chain *core.Blockchain, sender *keys.PrivateKey, n
 		},
 		Signers: []transaction.Signer{{Account: chain.GetNotaryContractScriptHash()}, {Account: sender.GetScriptHash()}},
 		Scripts: []transaction.Witness{
-			{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...), VerificationScript: []byte{}},
+			{InvocationScript: append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, make([]byte, keys.SignatureLen)...), VerificationScript: []byte{}},
 		},
 		NetworkFee: 2_0000_0000,
 	}
 	fallbackTx.Scripts = append(fallbackTx.Scripts, transaction.Witness{
-		InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, sender.SignHashable(uint32(testchain.Network()), fallbackTx)...),
+		InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, sender.SignHashable(uint32(testchain.Network()), fallbackTx)...),
 		VerificationScript: sender.PublicKey().GetVerificationScript(),
 	})
 	p := &payload.P2PNotaryRequest{
@@ -1846,7 +1846,7 @@ func createValidNotaryRequest(chain *core.Blockchain, sender *keys.PrivateKey, n
 		FallbackTransaction: fallbackTx,
 	}
 	p.Witness = transaction.Witness{
-		InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, sender.SignHashable(uint32(testchain.Network()), p)...),
+		InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, sender.SignHashable(uint32(testchain.Network()), p)...),
 		VerificationScript: sender.PublicKey().GetVerificationScript(),
 	}
 	return p
diff --git a/pkg/smartcontract/context/item_test.go b/pkg/smartcontract/context/item_test.go
index 21108aa4d..767e510d4 100644
--- a/pkg/smartcontract/context/item_test.go
+++ b/pkg/smartcontract/context/item_test.go
@@ -43,11 +43,11 @@ func TestContextItem_MarshalJSON(t *testing.T) {
 		Script: []byte{1, 2, 3},
 		Parameters: []smartcontract.Parameter{{
 			Type:  smartcontract.SignatureType,
-			Value: random.Bytes(64),
+			Value: random.Bytes(keys.SignatureLen),
 		}},
 		Signatures: map[string][]byte{
-			hex.EncodeToString(priv1.PublicKey().Bytes()): random.Bytes(64),
-			hex.EncodeToString(priv2.PublicKey().Bytes()): random.Bytes(64),
+			hex.EncodeToString(priv1.PublicKey().Bytes()): random.Bytes(keys.SignatureLen),
+			hex.EncodeToString(priv2.PublicKey().Bytes()): random.Bytes(keys.SignatureLen),
 		},
 	}
 
diff --git a/pkg/wallet/account.go b/pkg/wallet/account.go
index e1a7c30e3..4658d63f0 100644
--- a/pkg/wallet/account.go
+++ b/pkg/wallet/account.go
@@ -116,7 +116,7 @@ func (a *Account) SignTx(net netmode.Magic, t *transaction.Transaction) error {
 	}
 	sign := a.privateKey.SignHashable(uint32(net), t)
 
-	invoc := append([]byte{byte(opcode.PUSHDATA1), 64}, sign...)
+	invoc := append([]byte{byte(opcode.PUSHDATA1), keys.SignatureLen}, sign...)
 	if len(a.Contract.Parameters) == 1 {
 		t.Scripts[pos].InvocationScript = invoc
 	} else {