clean up

src/bin/client.rs

@@ -13,6 +13,14 @@ fn main() {
         Ok(mut stream) => {
             println!("Successfully connected to server");
 
+            let bob_init_pub_key = PublicKey::from([
+                0xe8, 0x98, 0xc, 0x86, 0xe0, 0x32, 0xf1, 0xeb,
+                0x29, 0x75, 0x5, 0x2e, 0x8d, 0x65, 0xbd, 0xdd,
+                0x15, 0xc3, 0xb5, 0x96, 0x41, 0x17, 0x4e, 0xc9,
+                0x67, 0x8a, 0x53, 0x78, 0x9d, 0x92, 0xc7, 0x54,
+            ]);
+            let (salsa_box, pub_key) = generate_box(bob_init_pub_key.clone());
+
             loop {
                 let mut buffer = String::new();
                 match std::io::stdin().read_line(&mut buffer) {
@@ -24,25 +32,6 @@ fn main() {
                         // Encryption
                         //
 
-                        // Generate a random secret key.
-                        // NOTE: The secret key bytes can be accessed by calling `secret_key.as_bytes()`
-                        let alice_secret_key = SecretKey::generate(&mut OsRng);
-
-                        // Get the public key for the secret key we just generated
-                        let alice_public_key_bytes = alice_secret_key.public_key().as_bytes().clone();
-
-                        // Obtain your recipient's public key.
-                        let bob_public_key = PublicKey::from([
-                            0xe8, 0x98, 0xc, 0x86, 0xe0, 0x32, 0xf1, 0xeb,
-                            0x29, 0x75, 0x5, 0x2e, 0x8d, 0x65, 0xbd, 0xdd,
-                            0x15, 0xc3, 0xb5, 0x96, 0x41, 0x17, 0x4e, 0xc9,
-                            0x67, 0x8a, 0x53, 0x78, 0x9d, 0x92, 0xc7, 0x54,
-                        ]);
-
-                        // Create a `SalsaBox` by performing Diffie-Hellman key agreement between
-                        // the two keys.
-                        let alice_box = SalsaBox::new(&bob_public_key, &alice_secret_key);
-
                         // Get a random nonce to encrypt the message under
                         let nonce = SalsaBox::generate_nonce(&mut OsRng);
 
@@ -50,7 +39,7 @@ fn main() {
                         let plaintext = buffer.trim().as_bytes();
 
                         // Encrypt the message using the box
-                        let ciphertext = alice_box.encrypt(&nonce, &plaintext[..]).expect("Fehler");
+                        let ciphertext = salsa_box.encrypt(&nonce, &plaintext[..]).expect("Fehler");
 
                         println!("Sending {0} as {1:?}", buffer.trim(), plaintext);
                         stream.write(buffer.as_bytes()).unwrap();
@@ -59,24 +48,8 @@ fn main() {
                         // Decryption
                         //
 
-                        // Either side can encrypt or decrypt messages under the Diffie-Hellman key
-                        // they agree upon. The example below shows Bob's side.
-                        let bob_secret_key = SecretKey::from([
-                            0xb5, 0x81, 0xfb, 0x5a, 0xe1, 0x82, 0xa1, 0x6f,
-                            0x60, 0x3f, 0x39, 0x27, 0xd, 0x4e, 0x3b, 0x95,
-                            0xbc, 0x0, 0x83, 0x10, 0xb7, 0x27, 0xa1, 0x1d,
-                            0xd4, 0xe7, 0x84, 0xa0, 0x4, 0x4d, 0x46, 0x1b
-                        ]);
-
-                        // Deserialize Alice's public key from bytes
-                        let alice_public_key = PublicKey::from(alice_public_key_bytes);
-
-                        // Bob can compute the same `SalsaBox` as Alice by performing the
-                        // key agreement operation.
-                        let bob_box = SalsaBox::new(&alice_public_key, &bob_secret_key);
-
                         // Decrypt the message, using the same randomly generated nonce
-                        let decrypted_plaintext = bob_box.decrypt(&nonce, &ciphertext[..]).expect("Fehler");
+                        let decrypted_plaintext = salsa_box.decrypt(&nonce, &ciphertext[..]).expect("Fehler");
                         let dec_plain_plaintext = std::str::from_utf8(&*decrypted_plaintext).expect("Nö");
                         assert_eq!(&plaintext[..], &decrypted_plaintext[..]);
 
@@ -94,4 +67,19 @@ fn main() {
         }
     }
     println!("Terminated.");
-} // the stream is closed here
+}
+
+fn generate_box(partner_public_key: PublicKey) -> (SalsaBox, PublicKey) {
+    // Generate a random secret key.
+    // NOTE: The secret key bytes can be accessed by calling `secret_key.as_bytes()`
+    let own_secret_key = SecretKey::generate(&mut OsRng);
+
+    // Get the public key for the secret key we just generated
+    let own_public_key = own_secret_key.public_key().clone();
+
+    // Create a `SalsaBox` by performing Diffie-Hellman key agreement between
+    // the two keys.
+    let salsa_box = SalsaBox::new(&partner_public_key, &own_secret_key);
+    (salsa_box, own_public_key)
+}
+