diff --git a/src/v4/aliyun_util.rs b/src/v4/aliyun_util.rs
index 4d12b7e..337fa91 100644
--- a/src/v4/aliyun_util.rs
+++ b/src/v4/aliyun_util.rs
@@ -18,10 +18,12 @@ struct Request {
     pub product: String,
     pub action: String,
     pub method: String,
+    pub endpoint: String,
     pub pathname: String,
     pub access_key: Option<AccessKey>,
     pub user_agent: String,
     pub sign_algorithm: SignAlgorithm,
+    pub query: BTreeMap<String, String>,
     pub headers: BTreeMap<String, String>,
     pub stream: Option<Vec<u8>>,
 }
@@ -29,7 +31,8 @@ struct Request {
 fn add_common_headers(header: &mut BTreeMap<String, String>, request: &Request) {
     let (ymd, date) = get_timestamp();
 
-    header.insert_kv(HEADER_HOST, "endpoint"); // TODO
+    let host = get_host(&request.endpoint);
+    header.insert_kv(HEADER_HOST, host);
     header.insert_kv(HEADER_X_ASC_VERSION, &request.version);
     header.insert_kv(HEADER_X_ASC_ACTION, &request.action);
     header.insert_kv(HEADER_USER_AGENT, &request.user_agent);
@@ -37,16 +40,14 @@ fn add_common_headers(header: &mut BTreeMap<String, String>, request: &Request)
     header.insert_kv(HEADER_X_ASC_SIGNATURE_NONCE, get_nonce());
     header.insert_kv(HEADER_ACCEPT, CONTENT_TYPE_APPLICATION_JSON);
 
-    // TODO BODY ...
-
-    // TODO signature ...
+    let digest_request_payload = digest_request_body(&request.sign_algorithm, &request.stream);
     match &request.sign_algorithm {
         SignAlgorithm::Sha1 => panic!("SHA1 in V4 is NOT supported!"),
         SignAlgorithm::Sha256 => {
-            header.insert_kv(HEADER_X_ASC_CONTENT_SHA256, "");
+            header.insert_kv(HEADER_X_ASC_CONTENT_SHA256, &digest_request_payload);
         }
         SignAlgorithm::Sm3 => {
-            header.insert_kv(HEADER_X_ASC_CONTENT_SM3, "");
+            header.insert_kv(HEADER_X_ASC_CONTENT_SM3, &digest_request_payload);
         }
     }
 
@@ -92,6 +93,27 @@ fn get_timestamp() -> (String, String) {
     ("yyyymmdd".into(), "yyyy-mm-dd".into())
 }
 
+fn digest_request_body(sign_algorithm: &SignAlgorithm, body: &Option<Vec<u8>>) -> String {
+    match body {
+        None => sign_algorithm.digest(&vec![]),
+        Some(body) => sign_algorithm.digest(body),
+    }
+}
+
+fn get_host(endpoint: &str) -> String {
+    let lower_endpoint = endpoint.to_ascii_lowercase();
+    let skip_chars = if lower_endpoint.starts_with("http://") {
+        7
+    } else if lower_endpoint.starts_with("https://") {
+        8
+    } else if lower_endpoint.starts_with("//") {
+        2
+    } else {
+        0
+    };
+    lower_endpoint.chars().skip(skip_chars).take_while(|c| *c != '/').collect()
+}
+
 fn get_nonce() -> String {
     let seq = SEQ.fetch_add(1, Ordering::Relaxed);
     let now = SystemTime::now();
@@ -227,6 +249,31 @@ fn test_get_nonce() {
     assert!(nonce.starts_with("nonce-"));
 }
 
+#[test]
+fn test_digest_request_body() {
+    assert_eq!("e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+               digest_request_body(&SignAlgorithm::Sha256, &None).as_str());
+    assert_eq!("ae6d8a1c07f438667618879eae74ffab84c236ea5d8ca52d5ca0523cc35e8bb9",
+               digest_request_body(&SignAlgorithm::Sha256, &Some("Test Body".as_bytes().to_vec())).as_str());
+    assert_eq!("1ab21d8355cfa17f8e61194831e81a8f22bec8c728fefb747ed035eb5082aa2b",
+               digest_request_body(&SignAlgorithm::Sm3, &None).as_str());
+    assert_eq!("487b3b171a56ba378f0bfd6d6e430774728aa23c13121eba18c54cf39feac0da",
+               digest_request_body(&SignAlgorithm::Sm3, &Some("Test Body".as_bytes().to_vec())).as_str());
+}
+
+#[test]
+fn test_get_host() {
+    assert_eq!("example.com", get_host("http://example.com").as_str());
+    assert_eq!("example.com", get_host("http://example.com/").as_str());
+    assert_eq!("example.com", get_host("http://example.com/path").as_str());
+    assert_eq!("example.com", get_host("https://example.com/path").as_str());
+    assert_eq!("example.com", get_host("HttPS://EXAMPLE.com/path").as_str());
+    assert_eq!("example.com", get_host("//EXAMPLE.com/path").as_str());
+    assert_eq!("example.com", get_host("EXAMPLE.com/path").as_str());
+    assert_eq!("example.com:8000", get_host("EXAMPLE.com:8000/path").as_str());
+    assert_eq!("example.com:8000", get_host("hTTPS://EXAMPLE.com:8000/path").as_str());
+}
+
 #[test]
 fn test_get_signing_key_sha256() {
     let signing_key = get_signing_key(