diff --git a/src/v4/access_keys.rs b/src/v4/access_key.rs
similarity index 56%
rename from src/v4/access_keys.rs
rename to src/v4/access_key.rs
index 02b3fe2..5bcc49f 100644
--- a/src/v4/access_keys.rs
+++ b/src/v4/access_key.rs
@@ -1,5 +1,8 @@
+use std::fmt::{Debug, Formatter};
+
 use zeroize::Zeroize;
 
+#[derive(Clone, PartialEq, Eq)]
 pub struct AccessKey {
     pub access_key_id: String,
     pub access_key_secret: String,
@@ -12,6 +15,12 @@ impl Drop for AccessKey {
     }
 }
 
+impl Debug for AccessKey {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "AccessKey{{ID: {}}}", &self.access_key_id)
+    }
+}
+
 pub struct DerivedAccessKey {
     pub access_key_id: String,
     pub derived_access_key_secret: Vec<u8>,
@@ -23,3 +32,9 @@ impl Drop for DerivedAccessKey {
         self.derived_access_key_secret.zeroize();
     }
 }
+
+impl Debug for DerivedAccessKey {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "DerivedAccessKey{{ID: {}}}", &self.access_key_id)
+    }
+}
\ No newline at end of file
diff --git a/src/v4/aliyun_util.rs b/src/v4/aliyun_util.rs
index a485188..46e1cb4 100644
--- a/src/v4/aliyun_util.rs
+++ b/src/v4/aliyun_util.rs
@@ -2,10 +2,14 @@ use std::collections::BTreeMap;
 
 use sm3::Digest;
 
-use crate::v4::access_keys::DerivedAccessKey;
-use crate::v4::algorithm::SignAlgorithm;
+use crate::v4::access_key::DerivedAccessKey;
 use crate::v4::common_util::{join_slices, percent_encode};
-use crate::v4::constants::{ALIYUN_V4, ALIYUN_V4_REQUEST, HEADER_CONTENT_TYPE, HEADER_HOST, HEADER_X_ACS_PREFIX, REGION_CENTER};
+use crate::v4::constant::{
+    ALIYUN_V4, ALIYUN_V4_REQUEST,
+    HEADER_CONTENT_TYPE,
+    HEADER_HOST, HEADER_X_ACS_PREFIX, REGION_CENTER,
+};
+use crate::v4::sign_algorithm::SignAlgorithm;
 
 fn get_authorization(sign_algorithm: SignAlgorithm,
                      access_key: &DerivedAccessKey,
diff --git a/src/v4/constants.rs b/src/v4/constant.rs
similarity index 86%
rename from src/v4/constants.rs
rename to src/v4/constant.rs
index b607e26..fcbede4 100644
--- a/src/v4/constants.rs
+++ b/src/v4/constant.rs
@@ -1,6 +1,3 @@
-pub(crate) const ACS4_HMAC_SHA256: &str = "ACS4-HMAC-SHA256";
-pub(crate) const ACS4_HMAC_SM3: &str = "ACS4-HMAC-SM3";
-
 pub(crate) const REGION_CENTER: &str = "center";
 pub(crate) const ALIYUN_V4: &str = "aliyun_v4";
 pub(crate) const ALIYUN_V4_REQUEST: &str = "aliyun_v4_request";
diff --git a/src/v4/mod.rs b/src/v4/mod.rs
index 19eaa72..63ed817 100644
--- a/src/v4/mod.rs
+++ b/src/v4/mod.rs
@@ -1,5 +1,5 @@
-mod constants;
-mod algorithm;
-mod access_keys;
+mod constant;
+mod sign_algorithm;
+mod access_key;
 mod common_util;
 mod aliyun_util;
diff --git a/src/v4/algorithm.rs b/src/v4/sign_algorithm.rs
similarity index 74%
rename from src/v4/algorithm.rs
rename to src/v4/sign_algorithm.rs
index 9d84461..2d57f06 100644
--- a/src/v4/algorithm.rs
+++ b/src/v4/sign_algorithm.rs
@@ -1,6 +1,8 @@
 use sm3::{Digest, Sm3};
 
-use crate::v4::constants::{ACS4_HMAC_SHA256, ACS4_HMAC_SM3};
+const ACS4_HMAC_SHA256: &str = "ACS4-HMAC-SHA256";
+const ACS4_HMAC_SM3: &str = "ACS4-HMAC-SM3";
+
 
 #[derive(Clone, Copy)]
 pub enum SignAlgorithm {
@@ -9,22 +11,29 @@ pub enum SignAlgorithm {
 }
 
 impl SignAlgorithm {
-    pub fn digest(&self, messge: &[u8]) -> String {
-        inner_digest(self, messge)
+    pub fn digest(&self, message: &[u8]) -> String {
+        inner_digest(self, message)
     }
 
     pub fn hmac_sign(&self, message: &[u8], key: &[u8]) -> Vec<u8> {
         inner_hmac_sign(self, message, key)
     }
 
+    #[inline]
     pub fn as_aliyun_name(&self) -> &'static str {
-        match self {
-            SignAlgorithm::Sha256 => ACS4_HMAC_SHA256,
-            SignAlgorithm::Sm3 => ACS4_HMAC_SM3,
-        }
+        inner_as_aliyun_name(self)
     }
 }
 
+#[inline]
+fn inner_as_aliyun_name(sign_algorithm: &SignAlgorithm) -> &'static str {
+    match sign_algorithm {
+        SignAlgorithm::Sha256 => ACS4_HMAC_SHA256,
+        SignAlgorithm::Sm3 => ACS4_HMAC_SM3,
+    }
+}
+
+#[inline]
 fn inner_digest(sign_algorithm: &SignAlgorithm, message: &[u8]) -> String {
     match sign_algorithm {
         SignAlgorithm::Sha256 => sha256::digest(message),
@@ -36,6 +45,7 @@ fn inner_digest(sign_algorithm: &SignAlgorithm, message: &[u8]) -> String {
     }
 }
 
+#[inline]
 fn inner_hmac_sign(sign_algorithm: &SignAlgorithm, message: &[u8], key: &[u8]) -> Vec<u8> {
     match sign_algorithm {
         SignAlgorithm::Sha256 => {