diff --git a/Cargo.toml b/Cargo.toml
index 4ac4d61..030ea21 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "double-ratchet-2"
-version = "0.1.0"
+version = "0.1.1"
 edition = "2018"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
@@ -11,7 +11,8 @@ rand_core = "0.5"
 hkdf = "0.11.0"
 hmac = "0.11.0"
 aes-gcm-siv = {version = "0.10.0"}
-ring-compat = {version = "0.2.1", features = ["digest"]}
+ring-compat = {version = "0.2.1", optional = true, features = ["digest"]}
+sha2 = {version = "0.9.5", optional = true}
 serde = {version = "1.0.125", default-features = false, features = ["derive"]}
 serde_bytes = "0.11.5"
 bincode = "1.3.3"
@@ -19,4 +20,8 @@ hashbrown = "0.11.2"
 
 [profile.release]
 lto = true
-opt-level = 3
\ No newline at end of file
+opt-level = 3
+
+[features]
+default = ["sha2"]
+ring = ["ring-compat/digest"]
\ No newline at end of file
diff --git a/src/kdf_chain.rs b/src/kdf_chain.rs
index 181ef94..7e41995 100644
--- a/src/kdf_chain.rs
+++ b/src/kdf_chain.rs
@@ -1,5 +1,11 @@
 use hmac::{Hmac, Mac, NewMac};
+
+#[cfg(feature = "ring")]
 use ring_compat::digest::Sha512;
+
+#[cfg(feature = "default")]
+use sha2::Sha512;
+
 use core::convert::TryInto;
 
 #[cfg(test)]
diff --git a/src/kdf_root.rs b/src/kdf_root.rs
index b08b8f4..cc971f3 100644
--- a/src/kdf_root.rs
+++ b/src/kdf_root.rs
@@ -1,6 +1,12 @@
 use x25519_dalek::SharedSecret;
 use hkdf::Hkdf;
+
+#[cfg(feature = "ring")]
 use ring_compat::digest::Sha512;
+
+#[cfg(feature = "default")]
+use sha2::Sha512;
+
 use core::convert::TryInto;
 
 #[cfg(test)]
diff --git a/src/lib.rs b/src/lib.rs
index ddacdac..741fdd9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,6 +1,5 @@
 #![no_std]
 #![allow(stable_features)]
-#![feature(alloc)]
 
 extern crate alloc;
 
@@ -8,5 +7,9 @@ mod aead;
 mod dh;
 mod kdf_root;
 mod kdf_chain;
-mod header;
+
+/// Providing essential functions
 pub mod ratchet;
+
+/// Message Header
+pub mod header;
diff --git a/src/ratchet.rs b/src/ratchet.rs
index 50e0ae4..fb54f8d 100644
--- a/src/ratchet.rs
+++ b/src/ratchet.rs
@@ -9,6 +9,7 @@ use crate::aead::{encrypt, decrypt};
 
 const MAX_SKIP: usize = 100;
 
+/// Object Representing Ratchet
 pub struct Ratchet {
     dhs: DhKeyPair,
     dhr: Option<PublicKey>,
diff --git a/tests/mod.rs b/tests/mod.rs
index 26f54a4..3dbd3db 100644
--- a/tests/mod.rs
+++ b/tests/mod.rs
@@ -36,9 +36,9 @@ fn ratchet_enc_skip() {
 #[should_panic]
 fn ratchet_panic_bob() {
     let sk = [1; 32];
-    let (mut bob_ratchet, public_key) = Ratchet::init_bob(sk);
+    let (mut bob_ratchet, _) = Ratchet::init_bob(sk);
     let data = include_bytes!("../src/header.rs").to_vec();
-    let (header, encrypted) = bob_ratchet.ratchet_encrypt(&data);
+    let (_, _) = bob_ratchet.ratchet_encrypt(&data);
 }
 
 #[test]