diff --git a/__crypto/curve25519/src/main.rs b/__crypto/curve25519/src/main.rs
index faffa22..d68bda5 100644
--- a/__crypto/curve25519/src/main.rs
+++ b/__crypto/curve25519/src/main.rs
@@ -1,9 +1,11 @@
+use std::convert::TryInto;
+
+use ed25519_dalek::{Keypair, Signer, Verifier};
 use rand::rngs::OsRng;
-use ed25519_dalek::{ Keypair, Signer, Verifier };
-use x25519_dalek::{ EphemeralSecret, PublicKey };
+use x25519_dalek::{EphemeralSecret, PublicKey};
 
 fn main() {
-    let mut csprng = OsRng{};
+    let mut csprng = OsRng {};
     let keypair = Keypair::generate(&mut csprng);
     println!("Key pair: {:#?}", keypair);
 
@@ -15,14 +17,29 @@ fn main() {
     println!("Verify result: {:?}", public_key.verify(message, &signature));
 
     // key exchange
+    println!("{}", "-".repeat(88));
     let alice_secret = EphemeralSecret::new(OsRng);
     let alice_public = PublicKey::from(&alice_secret);
     let bob_secret = EphemeralSecret::new(OsRng);
     let bob_public = PublicKey::from(&bob_secret);
-    
+
     let alice_shared_secret = alice_secret.diffie_hellman(&bob_public);
     let bob_shared_secret = bob_secret.diffie_hellman(&alice_public);
 
+    println!("Alice public key   : {}", hex::encode(alice_public.as_bytes()));
+    println!("Bob   public key   : {}", hex::encode(bob_public.as_bytes()));
+
     println!("Alice shared secret: {}", hex::encode(alice_shared_secret.as_bytes()));
     println!("Bob   shared secret: {}", hex::encode(bob_shared_secret.as_bytes()));
+
+    println!("{}", "-".repeat(88));
+    let public_key_bytes = hex::decode("7FEBAAB0D80CED24730B613F3D86924560EBCF13A838DEBC065F63C69C24C61E").unwrap();
+    let public_key_bytes: [u8; 32] = public_key_bytes.try_into().unwrap();
+    let public_key_card = PublicKey::from(public_key_bytes);
+    println!("Public key card: {}", hex::encode(public_key_card.as_bytes()));
+    let new_secret = EphemeralSecret::new(OsRng);
+    let new_public = PublicKey::from(&new_secret);
+    println!("New public key: {}", hex::encode(new_public.as_bytes()));
+    let new_card_shared_secret = new_secret.diffie_hellman(&public_key_card);
+    println!("New&card shared secret: {}", hex::encode(new_card_shared_secret.as_bytes()));
 }