validate non-zero aes key and other refactoring

pkg/meta/internal/crypto/aes.go

@@ -31,20 +31,22 @@ func (ks KeySize) IsValid() bool {
 var ErrShortCipherText = errors.New("ciphertext too short")
 var ErrNoEncryptionKey = errors.New("encryption key is required")
 var ErrInvalidKeySize = errors.New("invalid key size: must be 16, 24, or 32 bytes")
+var ErrZeroKey = errors.New("encryption key cannot be all zeros")
 
-// NewKey generates a random AES key of the specified size.
-// If no size is provided, it defaults to KeySize256 (32 bytes).
+// GenerateKey generates a random AES key of default size KeySize256 (32 bytes).
 // Returns an error if the specified size is invalid or if key generation fails.
-func NewKey(size ...KeySize) ([]byte, error) {
-	keySize := KeySize256
-	if len(size) > 0 {
-		keySize = size[0]
-		if !keySize.IsValid() {
-			return nil, ErrInvalidKeySize
-		}
+func GenerateKey() ([]byte, error) {
+	return GenerateKeyWithSize(KeySize256)
+}
+
+// GenerateKeyWithSize generates a random AES key of the specified size.
+// Returns an error if the specified size is invalid or if key generation fails.
+func GenerateKeyWithSize(size KeySize) ([]byte, error) {
+	if !size.IsValid() {
+		return nil, ErrInvalidKeySize
 	}
 
-	key := make([]byte, keySize)
+	key := make([]byte, size)
 	if _, err := io.ReadFull(rand.Reader, key); err != nil {
 		return nil, fmt.Errorf("failed to generate AES key: %w", err)
 	}
@@ -119,5 +121,12 @@ func validateAESKey(key []byte) error {
 		return ErrInvalidKeySize
 	}
 
-	return nil
+	// check if key is all zeros
+	for _, b := range key {
+		if b != 0 {
+			return nil
+		}
+	}
+
+	return ErrZeroKey
 }

pkg/meta/internal/crypto/aes_test.go

@@ -3,7 +3,6 @@ package crypto
 import (
 	"bytes"
 	"crypto/rand"
-	"fmt"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -13,38 +12,42 @@ func TestAESEncryption(t *testing.T) {
 	t.Parallel()
 
 	key := make([]byte, 32) // generated random 32-byte key
-	_, err := rand.Read(key)
-	require.NoError(t, err)
+	_, errKey := rand.Read(key)
+	require.NoError(t, errKey)
 
 	tests := []struct {
 		name    string
 		data    []byte
 		key     []byte
-		wantErr bool
+		wantErr error
 	}{
 		{
-			name:    "valid encryption/decryption",
-			data:    []byte("hello world"),
-			key:     key,
-			wantErr: false,
+			name: "valid encryption/decryption",
+			data: []byte("hello world"),
+			key:  key,
 		},
 		{
 			name:    "nil key returns error",
 			data:    []byte("hello world"),
 			key:     nil,
-			wantErr: true,
+			wantErr: ErrNoEncryptionKey,
 		},
 		{
-			name:    "empty data",
-			data:    []byte{},
-			key:     key,
-			wantErr: false,
+			name: "empty data",
+			data: []byte{},
+			key:  key,
 		},
 		{
 			name:    "invalid key size",
 			data:    []byte("hello world"),
 			key:     make([]byte, 31),
-			wantErr: true,
+			wantErr: ErrInvalidKeySize,
+		},
+		{
+			name:    "zero key returns error",
+			data:    []byte("hello world"),
+			key:     make([]byte, 32),
+			wantErr: ErrZeroKey,
 		},
 	}
 
@@ -54,14 +57,13 @@ func TestAESEncryption(t *testing.T) {
 			t.Parallel()
 
 			encrypted, err := EncryptWithAESKey(tt.data, tt.key)
-			if tt.wantErr {
-				require.Error(t, err)
+			if tt.wantErr != nil {
+				require.ErrorIs(t, err, tt.wantErr)
+
 				return
 			}
 			require.NoError(t, err)
 
-			fmt.Println(string(encrypted))
-
 			decrypted, err := DecryptStringWithAESKey(encrypted, tt.key)
 			require.NoError(t, err)