diff --git a/cryptor/crypto_internal.go b/cryptor/crypto_internal.go
index 6005346..cbdd186 100644
--- a/cryptor/crypto_internal.go
+++ b/cryptor/crypto_internal.go
@@ -2,11 +2,11 @@ package cryptor
 
 import "bytes"
 
-func generateAesKey(key []byte) []byte {
-	genKey := make([]byte, 16)
+func generateAesKey(key []byte, size int) []byte {
+	genKey := make([]byte, size)
 	copy(genKey, key)
-	for i := 16; i < len(key); {
-		for j := 0; j < 16 && i < len(key); j, i = j+1, i+1 {
+	for i := size; i < len(key); {
+		for j := 0; j < size && i < len(key); j, i = j+1, i+1 {
 			genKey[j] ^= key[i]
 		}
 	}
diff --git a/cryptor/encrypt.go b/cryptor/encrypt.go
index 6f43cbe..cdca8a0 100644
--- a/cryptor/encrypt.go
+++ b/cryptor/encrypt.go
@@ -23,6 +23,11 @@ import (
 // len(key) should be 16, 24 or 32.
 // Play: https://go.dev/play/p/jT5irszHx-j
 func AesEcbEncrypt(data, key []byte) []byte {
+	size := len(key)
+	if size != 16 && size != 24 && size != 32 {
+		panic("key length shoud be 16 or 24 or 32")
+	}
+
 	length := (len(data) + aes.BlockSize) / aes.BlockSize
 	plain := make([]byte, length*aes.BlockSize)
 
@@ -34,7 +39,7 @@ func AesEcbEncrypt(data, key []byte) []byte {
 	}
 
 	encrypted := make([]byte, len(plain))
-	cipher, _ := aes.NewCipher(generateAesKey(key))
+	cipher, _ := aes.NewCipher(generateAesKey(key, size))
 
 	for bs, be := 0, cipher.BlockSize(); bs <= len(data); bs, be = bs+cipher.BlockSize(), be+cipher.BlockSize() {
 		cipher.Encrypt(encrypted[bs:be], plain[bs:be])
@@ -47,7 +52,11 @@ func AesEcbEncrypt(data, key []byte) []byte {
 // len(key) should be 16, 24 or 32.
 // Play: https://go.dev/play/p/jT5irszHx-j
 func AesEcbDecrypt(encrypted, key []byte) []byte {
-	cipher, _ := aes.NewCipher(generateAesKey(key))
+	size := len(key)
+	if size != 16 && size != 24 && size != 32 {
+		panic("key length shoud be 16 or 24 or 32")
+	}
+	cipher, _ := aes.NewCipher(generateAesKey(key, size))
 	decrypted := make([]byte, len(encrypted))
 
 	for bs, be := 0, cipher.BlockSize(); bs < len(encrypted); bs, be = bs+cipher.BlockSize(), be+cipher.BlockSize() {