diff --git a/pkg/crypto/keys/nep2.go b/pkg/crypto/keys/nep2.go
index abfa9277d..dd4ab206d 100644
--- a/pkg/crypto/keys/nep2.go
+++ b/pkg/crypto/keys/nep2.go
@@ -7,6 +7,7 @@ import (
 
 	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/base58"
+	"github.com/nspcc-dev/neo-go/pkg/util/slice"
 	"golang.org/x/crypto/scrypt"
 	"golang.org/x/text/unicode/norm"
 )
@@ -52,10 +53,15 @@ func NEP2Encrypt(priv *PrivateKey, passphrase string, params ScryptParams) (s st
 	if err != nil {
 		return s, err
 	}
+	defer slice.Clean(derivedKey)
 
 	derivedKey1 := derivedKey[:32]
 	derivedKey2 := derivedKey[32:]
-	xr := xor(priv.Bytes(), derivedKey1)
+
+	privBytes := priv.Bytes()
+	defer slice.Clean(privBytes)
+	xr := xor(privBytes, derivedKey1)
+	defer slice.Clean(xr)
 
 	encrypted, err := aesEncrypt(xr, derivedKey2)
 	if err != nil {
@@ -93,6 +99,7 @@ func NEP2Decrypt(key, passphrase string, params ScryptParams) (*PrivateKey, erro
 	if err != nil {
 		return nil, err
 	}
+	defer slice.Clean(derivedKey)
 
 	derivedKey1 := derivedKey[:32]
 	derivedKey2 := derivedKey[32:]
@@ -102,8 +109,10 @@ func NEP2Decrypt(key, passphrase string, params ScryptParams) (*PrivateKey, erro
 	if err != nil {
 		return nil, err
 	}
+	defer slice.Clean(decrypted)
 
 	privBytes := xor(decrypted, derivedKey1)
+	defer slice.Clean(privBytes)
 
 	// Rebuild the private key.
 	privKey, err := NewPrivateKeyFromBytes(privBytes)
diff --git a/pkg/crypto/keys/private_key.go b/pkg/crypto/keys/private_key.go
index 775c8e556..744e49ab1 100644
--- a/pkg/crypto/keys/private_key.go
+++ b/pkg/crypto/keys/private_key.go
@@ -13,6 +13,7 @@ import (
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
 	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/util/slice"
 	"github.com/nspcc-dev/rfc6979"
 )
 
@@ -48,6 +49,7 @@ func NewPrivateKeyFromHex(str string) (*PrivateKey, error) {
 	if err != nil {
 		return nil, err
 	}
+	defer slice.Clean(b)
 	return NewPrivateKeyFromBytes(b)
 }
 
diff --git a/pkg/crypto/keys/wif.go b/pkg/crypto/keys/wif.go
index 0e4d57b3d..7da78ea8e 100644
--- a/pkg/crypto/keys/wif.go
+++ b/pkg/crypto/keys/wif.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 
 	"github.com/nspcc-dev/neo-go/pkg/encoding/base58"
+	"github.com/nspcc-dev/neo-go/pkg/util/slice"
 )
 
 const (
@@ -53,6 +54,7 @@ func WIFDecode(wif string, version byte) (*WIF, error) {
 	if err != nil {
 		return nil, err
 	}
+	defer slice.Clean(b)
 
 	if version == 0x00 {
 		version = WIFVersion