Refactor API

README.md

@@ -10,13 +10,16 @@ Basic usage:
 ```rust
 let claims = ...; // note : claims must be serializable
 
-// Generate a key pair. Public and private key are both serializable
-let (pub_key, priv_key) = generate_ec384_keypair().unwrap();
+// Generate a key pair. Private and public key are both serializable
+let priv_key = JWTPrivateKey::generate_ec384_signing_key().unwrap();
+let pub_key = priv_key.to_public_key().unwrap();
 
 // Create a JWT for the given claims (note: standard claims: sub, iss, ...) are not
 // automatically added if they are missing
-let jwt = sign_jwt(&priv_key, &claims).expect("Failed to sign JWT!");
+let jwt = priv_key.sign_jwt(&claims).expect("Failed to sign JWT!");
 
 // Validate signed JWT
-let claims_out = validate_jwt::<Claims>(&pub_key, &jwt).expect("Failed to validate JWT!");
+let claims_out = pub_key
+            .validate_jwt::<Claims>(&jwt)
+            .expect("Failed to validate JWT!");
 ```