diff --git a/data_test.go b/data_test.go
index e3c8cea..54555d6 100644
--- a/data_test.go
+++ b/data_test.go
@@ -129,6 +129,10 @@ var cmplNum2 = complex(3, 4)
 
 // 字符串
 var strHello = "Hello World! 你好！"
+var strHello2 = "Hello World! 你好，世界！"
+var strHelloEmoji = "Hello World! 你好，世界！안녕, 세계！ Olá mundo,With Emojis:😃🐳📜💯⌚"
+var strJson = `{"id":9999,"url":"https://baidu.com"}`
+var strEmptyMd5 = "d41d8cd98f00b204e9800998ecf8427e"
 var b64Hello = "SGVsbG8gV29ybGQhIOS9oOWlve+8gQ=="
 var strHelloHex = "48656c6c6f20576f726c642120e4bda0e5a5bdefbc81" //strHello的16进制
 var utf8Hello = "你好，世界！"
diff --git a/encrypt.go b/encrypt.go
index 6c55686..d175238 100644
--- a/encrypt.go
+++ b/encrypt.go
@@ -84,7 +84,7 @@ func (ke *LkkEncrypt) Base64UrlDecode(str []byte) ([]byte, error) {
 
 // AuthCode 授权码编码或解码;
 // encode为true时编码,为false解码;
-// expiry为加密时的有效期,单位秒,为0时代表永久(100年);
+// expiry为加密时的有效期,单位秒,0为永久(100年),负数为已过期;
 // 返回结果为加密/解密的字符串和有效期时间戳.
 func (ke *LkkEncrypt) AuthCode(str, key []byte, encode bool, expiry int64) ([]byte, int64) {
 	// DYNAMIC_KEY_LEN 动态密钥长度，相同的明文会生成不同密文就是依靠动态密钥
diff --git a/encrypt_test.go b/encrypt_test.go
index 8ff5e13..4734c71 100644
--- a/encrypt_test.go
+++ b/encrypt_test.go
@@ -117,6 +117,20 @@ func TestEncrypt_AuthCode(t *testing.T) {
 	res2, exp = KEncr.AuthCode([]byte(strSha512), bytSpeedLight, false, 0)
 	assert.Empty(t, res2)
 
+	//其他
+	str1 := []byte("8c9eb7905a6SdXZfm-GoJpYKu6CzMgF0I-7neF-x3UKIUpYuIZSnK_2ZqaYSZlZw0Ofzwa2Bn0QZ6b4SLzSz")
+	str2 := []byte("b42374af3DqX22zi207OJXsz6xP2vEXto39TPK_UzcJOdDZV0kQHPUFm5JOw-aWISFi0snglsrYtp5tpYGRuhgw50TPY8UnFSf912uZI38vGON0KHqAgCatmtdoBZ4VJI6IkHio-JLxbt8hkuCz1HCOElUkZxBMnGUle")
+	str3 := []byte("52a0945eK4NyxvnjEBnPlToROzO4KLKE9VvrqtxAiLPVPDK-HkvzahyMbxydmSifc3TQIo4mbsi9gzq7vbJ64YzpB_DP")
+
+	res2, exp = KEncr.AuthCode(str1, []byte(strEmptyMd5), false, 0)
+	assert.Equal(t, string(res2), strHello2)
+
+	res2, exp = KEncr.AuthCode(str2, []byte(strEmptyMd5), false, 0)
+	assert.Equal(t, string(res2), strHelloEmoji)
+
+	res2, exp = KEncr.AuthCode(str3, []byte(strEmptyMd5[0:16]), false, 0)
+	assert.Equal(t, string(res2), strJson)
+
 	//不合法
 	KEncr.AuthCode([]byte("7caeNfPt/N1zHdj5k/7i7pol6NHsVs0Cji7c15h4by1RYcrBoo7EEw=="), bytSpeedLight, false, 0)
 	KEncr.AuthCode([]byte("7caeNfPt/N1zHdj5k/7i7pol6N"), bytSpeedLight, false, 0)
diff --git a/string_test.go b/string_test.go
index c63c93c..322cd9c 100644
--- a/string_test.go
+++ b/string_test.go
@@ -26,13 +26,15 @@ func TestString_Md5Byte_Md5_IsMd5(t *testing.T) {
 	res2 = KStr.Md5Byte(bytsHello)
 	res4 = KStr.Md5(strHello)
 	assert.Equal(t, string(res2), res4)
+	chk = KStr.IsMd5(res4)
+	assert.True(t, chk)
+
+	res3 = KStr.Md5("")
+	assert.Equal(t, res3, strEmptyMd5)
 
 	res3 = KStr.Md5(strHello, 16)
 	chk = KStr.IsMd5(res3)
 	assert.False(t, chk)
-
-	chk = KStr.IsMd5(res4)
-	assert.True(t, chk)
 }
 
 func BenchmarkString_Md5Byte(b *testing.B) {