diff --git a/src/hashes/sha1.rs b/src/hashes/sha1.rs
index 8e013af..ca0dc8d 100644
--- a/src/hashes/sha1.rs
+++ b/src/hashes/sha1.rs
@@ -1,20 +1,28 @@
 use super::*;
+use ::sha1::digest::core_api::CoreWrapper;
+use ::sha1::{Digest, Sha1, Sha1Core};
 
 pub struct SHA1 {
     hash: BITS160,
+    hasher: CoreWrapper<Sha1Core>,
 }
 
 impl Hasher for SHA1 {
     fn new() -> Self {
-        SHA1 { hash: [0; 20] }
+        SHA1 {
+            hash: [0; 20],
+            hasher: Sha1::new(),
+        }
     }
 
     fn digest(&mut self, bytes: impl AsRef<[u8]>) {
-        todo!()
+        self.hasher.update(bytes.as_ref())
     }
 
-    fn complete(self) -> HashReturn {
-        todo!()
+    fn complete(mut self) -> HashReturn {
+        let res = self.hasher.finalize();
+        self.hash.copy_from_slice(&res);
+        HashReturn::SHA1(self.hash)
     }
 }
 
@@ -24,6 +32,17 @@ mod test {
 
     #[test]
     fn test_sha1_hash() {
-        todo!();
+        let input = "HelloWorld";
+        let expected_output = "db8ac1c259eb89d4a131b253bacfca5f319d54f2";
+
+        let mut sha1 = SHA1::new();
+
+        sha1.digest(input);
+
+        let result = sha1.complete().into_bytes();
+
+        let hash_out = crate::hex_table::u8_array_to_lower_hex_string(&result).unwrap();
+
+        assert_eq!(hash_out, expected_output);
     }
 }