diff --git a/key/key_test.go b/key/key_test.go
index d2b3104..e84d99b 100644
--- a/key/key_test.go
+++ b/key/key_test.go
@@ -27,9 +27,19 @@ func TestPublicKey(t *testing.T) {
 		require.Equal(t, "", hex.EncodeToString(b.Bytes()))
 	})
 
-	t.Run("invalid key", func(t *testing.T) {
-		_, err := NewPublicKey("123")
-		require.EqualError(t, err, "wrong prefix")
+	t.Run("wrong key len", func(t *testing.T) {
+		_, err := NewPublicKey("")
+		require.ErrorIs(t, err, ErrWrongKeyLen)
+	})
+
+	t.Run("wrong prefix", func(t *testing.T) {
+		_, err := NewPublicKey("SSS11111111111111111111111111111111111111111111111111")
+		require.ErrorIs(t, err, ErrWrongPrefix)
+	})
+
+	t.Run("wrong check sum", func(t *testing.T) {
+		_, err := NewPublicKey("SCR11111111111111111111111111111111111111111111111111")
+		require.ErrorIs(t, err, ErrWrongChecksum)
 	})
 
 	t.Run("public key from string", func(t *testing.T) {
@@ -89,15 +99,13 @@ func TestSignAndValidate(t *testing.T) {
 	sig := pk.Sign(hash)
 	require.Equal(t, sigHex, hex.EncodeToString(sig))
 
-	ok, err := pk.PublicKey().Verify(hash, sig)
+	err = pk.PublicKey().Verify(hash, sig)
 	require.NoError(t, err)
-	require.True(t, ok)
 
-	t.Run("validate with wrong key return false", func(t *testing.T) {
+	t.Run("validate with wrong key key mismatch", func(t *testing.T) {
 		wrogKey, err := NewPublicKey("SCR5jPZF7PMgTpLqkdfpMu8kXea8Gio6E646aYpTgcjr9qMLrAgnL")
 		require.NoError(t, err)
-		ok, err := wrogKey.Verify(hash, sig)
-		require.NoError(t, err)
-		require.False(t, ok)
+		err = wrogKey.Verify(hash, sig)
+		require.ErrorIs(t, err, ErrKeyMismatch)
 	})
 }
diff --git a/key/publickey.go b/key/publickey.go
index a70bafa..de14858 100644
--- a/key/publickey.go
+++ b/key/publickey.go
@@ -3,6 +3,7 @@ package key
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"strings"
 
 	"github.com/scorum/scorum-go/encoding/transaction"
@@ -15,11 +16,14 @@ import (
 const (
 	publicKeyPrefix = "SCR"
 	checkSumLen     = 4
+	keyLen          = 53
 )
 
 var (
 	ErrWrongPrefix   = errors.New("wrong prefix")
 	ErrWrongChecksum = errors.New("wrong check sum")
+	ErrWrongKeyLen   = errors.New("wrong key len")
+	ErrKeyMismatch   = errors.New("key mismatch")
 )
 
 type PublicKey struct {
@@ -27,10 +31,16 @@ type PublicKey struct {
 }
 
 func NewPublicKey(pubKey string) (*PublicKey, error) {
+	if len(pubKey) != keyLen {
+		return nil, ErrWrongKeyLen
+	}
+
 	if !strings.HasPrefix(pubKey, publicKeyPrefix) {
 		return nil, ErrWrongPrefix
 	}
+
 	keyWithChecksum := base58.Decode(pubKey[len(publicKeyPrefix):])
+
 	key := keyWithChecksum[:len(keyWithChecksum)-checkSumLen]
 
 	h := ripemd160.New()
@@ -69,13 +79,17 @@ func (p *PublicKey) Serialize() []byte {
 	return p.raw.SerializeCompressed()
 }
 
-func (p *PublicKey) Verify(digest []byte, signature []byte) (bool, error) {
+func (p *PublicKey) Verify(digest []byte, signature []byte) error {
 	pub, _, err := btcec.RecoverCompact(btcec.S256(), signature, digest)
 	if err != nil {
-		return false, err
+		return fmt.Errorf("recover compact: %w", err)
+	}
+
+	if !p.raw.IsEqual(pub) {
+		return ErrKeyMismatch
 	}
 
-	return p.raw.IsEqual(pub), nil
+	return nil
 }
 
 func (p *PublicKey) MarshalTransaction(encoder *transaction.Encoder) error {
diff --git a/sign/signed_transaction.go b/sign/signed_transaction.go
index 57e3528..93a2d65 100644
--- a/sign/signed_transaction.go
+++ b/sign/signed_transaction.go
@@ -67,24 +67,24 @@ func (tx *SignedTransaction) Sign(chainID []byte, keys ...*key.PrivateKey) error
 	return nil
 }
 
-func (tx *SignedTransaction) Verify(chainID []byte, keys ...*key.PublicKey) (bool, error) {
+func (tx *SignedTransaction) Verify(chainID []byte, keys ...*key.PublicKey) error {
 	dig, err := tx.Digest(chainID)
 	if err != nil {
-		return false, fmt.Errorf("failed to get digest: %w", err)
+		return fmt.Errorf("failed to get digest: %w", err)
 	}
 
 	for _, signature := range tx.Signatures {
 		sig, err := hex.DecodeString(signature)
 		if err != nil {
-			return false, fmt.Errorf("failed to decode signature: %w", err)
+			return fmt.Errorf("failed to decode signature: %w", err)
 		}
 
 		for _, k := range keys {
-			if ok, err := k.Verify(dig, sig); err != nil || !ok {
-				return ok, fmt.Errorf("verify signature: %w", err)
+			if err := k.Verify(dig, sig); err != nil {
+				return fmt.Errorf("verify signature: %w", err)
 			}
 		}
 	}
 
-	return true, nil
+	return nil
 }
diff --git a/sign/signed_transaction_test.go b/sign/signed_transaction_test.go
index 9647f60..b07b479 100644
--- a/sign/signed_transaction_test.go
+++ b/sign/signed_transaction_test.go
@@ -72,7 +72,5 @@ func TestTransaction_Verify(t *testing.T) {
 	pubKey, err := key.NewPublicKey("SCR7cTf2Dx9rxffs6E2z2pdn5cLMneo3AAFSsF9g4SaVviCYdfQ63")
 	require.NoError(t, err)
 
-	res, err := stx.Verify(TestNetChainID, pubKey)
-	require.NoError(t, err)
-	require.True(t, res)
+	require.NoError(t, stx.Verify(TestNetChainID, pubKey))
 }
diff --git a/types/key_test.go b/types/key_test.go
index 20bbc5d..d82f453 100644
--- a/types/key_test.go
+++ b/types/key_test.go
@@ -11,27 +11,12 @@ import (
 )
 
 func TestPublicKey_MarshalTransaction(t *testing.T) {
-	t.Run("empty key", func(t *testing.T) {
-		var key PublicKey
-		var b bytes.Buffer
-		encoder := transaction.NewEncoder(&b)
-		require.EqualError(t, key.MarshalTransaction(encoder), "wrong prefix")
-		require.Equal(t, "", hex.EncodeToString(b.Bytes()))
-	})
+	var (
+		b       bytes.Buffer
+		key     PublicKey = "SCR5jPZF7PMgTpLqkdfpMu8kXea8Gio6E646aYpTgcjr9qMLrAgnL"
+		encoder           = transaction.NewEncoder(&b)
+	)
 
-	t.Run("invalid key", func(t *testing.T) {
-		key := PublicKey("123")
-		var b bytes.Buffer
-		encoder := transaction.NewEncoder(&b)
-		require.EqualError(t, key.MarshalTransaction(encoder), "wrong prefix")
-		require.Equal(t, "", hex.EncodeToString(b.Bytes()))
-	})
-
-	t.Run("valid key", func(t *testing.T) {
-		key := PublicKey("SCR5jPZF7PMgTpLqkdfpMu8kXea8Gio6E646aYpTgcjr9qMLrAgnL")
-		var b bytes.Buffer
-		encoder := transaction.NewEncoder(&b)
-		require.NoError(t, key.MarshalTransaction(encoder))
-		require.Equal(t, "026f0896f24d94252c351715bfe6052bbf9ea820e805bd47c2496c626d3467da5d", hex.EncodeToString(b.Bytes()))
-	})
+	require.NoError(t, key.MarshalTransaction(encoder))
+	require.Equal(t, "026f0896f24d94252c351715bfe6052bbf9ea820e805bd47c2496c626d3467da5d", hex.EncodeToString(b.Bytes()))
 }