progress commit.

crates/obfs4/src/common/mod.rs

@@ -5,7 +5,7 @@ use hmac::Hmac;
 use sha2::Sha256;
 
 pub(crate) mod ct;
-pub(crate) mod curve25519;
+pub(crate) mod x25519_elligator2;
 pub(crate) mod kdf;
 
 mod skip;

crates/obfs4/src/common/curve25519.rs → crates/obfs4/src/common/x25519_elligator2.rs

@@ -8,7 +8,7 @@
 pub use x25519_dalek::{PublicKey, SharedSecret, StaticSecret};
 pub use curve25519_elligator2::elligator2::representative_from_privkey;
 
-pub(crate) struct EphemeralSecret (x25519_dalek::EphemeralSecret, u8);
+pub(crate) struct EphemeralSecret (x25519_dalek::StaticSecret, u8);
 
 impl EphemeralSecret {
     pub(crate) fn random() -> Self {}
@@ -117,7 +117,7 @@ impl<'a> From<&'a [u8; 32]> for PublicRepresentative {
 impl<'a> From<&'a EphemeralSecret> for Option<PublicRepresentative> {
     /// Given an x25519 [`EphemeralSecret`] key, compute its corresponding [`PublicRepresentative`].
     fn from(secret: &'a EphemeralSecret) -> Option<PublicRepresentative> {
-        let repres = representative_from_privkey(&secret.0, secret.1);
+        let repres = representative_from_privkey(&secret.0.to_bytes(), secret.1);
         let res: Option<[u8; 32]> = repres;
         Some(PublicRepresentative(res?))
     }
@@ -187,7 +187,12 @@ impl Keys {
     /// Generate a new Elligator2 representable ['StaticSecret'].
     pub fn random_static() -> StaticSecret {
         let mut private = StaticSecret::random();
-        let mut repres: Option<PublicRepresentative> = (&private).into();
+        let mut tweak = [0u8];
+        getrandom::getrandom(&mut tweak).expect("failed to get random bytes");
+
+        let mut key = EphemeralSecret(private, tweak[0]);
+
+        let mut repres: Option<PublicRepresentative> = &key.into();
 
         for _ in 0..Self::RETRY_LIMIT {
             if repres.is_some() {

crates/obfs4/src/constants.rs

@@ -3,7 +3,7 @@
 use tor_llcrypto::pk::rsa::RSA_ID_LEN;
 
 use crate::{
-    common::{curve25519::REPRESENTATIVE_LENGTH, drbg},
+    common::{x25519_elligator2::REPRESENTATIVE_LENGTH, drbg},
     framing,
     handshake::AUTHCODE_LENGTH,
 };

crates/obfs4/src/framing/handshake.rs

@@ -1,6 +1,6 @@
 use crate::{
     common::{
-        curve25519::{PublicKey, PublicRepresentative},
+        x25519_elligator2::{PublicKey, PublicRepresentative},
         HmacSha256,
     },
     constants::*,

crates/obfs4/src/framing/messages_v1/crypto.rs

@@ -58,7 +58,7 @@ impl Message for KyberAcceptMessage {
 mod tests {
     use pqc_kyber::*;
 
-    use crate::common::curve25519::{PublicKey, Representable};
+    use crate::common::x25519_elligator2::{PublicKey, Keys};
     use crate::handshake::Obfs4NtorSecretKey;
 
     type Result<T> = std::result::Result<T, Error>;
@@ -124,7 +124,7 @@ mod tests {
         let mut rng = rand::thread_rng();
 
         // Generate Keypair
-        let alice_secret = Representable::ephemeral_from_rng(&mut rng);
+        let alice_secret = Keys::ephemeral_from_rng(&mut rng);
         let alice_public = PublicKey::from(&alice_secret);
         let keys_alice = keypair(&mut rng)?;
         // alice -> bob public keys
@@ -133,7 +133,7 @@ mod tests {
 
         assert_eq!(kyber1024x_pubkey.len(), 1600);
 
-        let bob_secret = Representable::ephemeral_from_rng(&mut rng);
+        let bob_secret = Keys::ephemeral_from_rng(&mut rng);
         let bob_public = PublicKey::from(&bob_secret);
 
         // Bob encapsulates a shared secret using Alice's public key

crates/obfs4/src/handshake/handshake_client.rs

@@ -1,7 +1,7 @@
 use super::*;
 use crate::{
     common::{
-        curve25519::{PublicRepresentative, REPRESENTATIVE_LENGTH},
+        x25519_elligator2::{PublicRepresentative, REPRESENTATIVE_LENGTH},
         HmacSha256,
     },
     framing::handshake::{ClientHandshakeMessage, ServerHandshakeMessage},
@@ -49,7 +49,7 @@ pub(super) fn client_handshake_obfs4(
     materials: &HandshakeMaterials,
 ) -> Result<(NtorHandshakeState, Vec<u8>)> {
     let rng = rand::thread_rng();
-    let my_sk = Representable::static_from_rng(rng);
+    let my_sk = Keys::static_from_rng(rng);
     client_handshake_obfs4_no_keygen(my_sk, materials.clone())
 }
 

crates/obfs4/src/handshake/handshake_server.rs

@@ -1,7 +1,7 @@
 use super::*;
 use crate::{
     common::{
-        curve25519::{PublicRepresentative, REPRESENTATIVE_LENGTH},
+        x25519_elligator2::{PublicRepresentative, REPRESENTATIVE_LENGTH},
         HmacSha256,
     },
     framing::{build_and_marshall, ClientHandshakeMessage, MessageTypes, ServerHandshakeMessage},
@@ -56,7 +56,7 @@ impl Server {
         T: AsRef<[u8]>,
     {
         let rng = thread_rng();
-        let session_sk = Representable::ephemeral_from_rng(rng);
+        let session_sk = Keys::ephemeral_from_rng(rng);
 
         self.server_handshake_obfs4_no_keygen(session_sk, msg, materials)
     }

crates/obfs4/src/handshake/integration.rs

@@ -267,8 +267,8 @@ fn about_half() -> Result<()> {
     let mut not_found = 0;
     let mut not_match = 0;
     for _ in 0..1_000 {
-        let sk = curve25519::StaticSecret::random_from_rng(&mut rng);
-        let rp: Option<curve25519::PublicRepresentative> = (&sk).into();
+        let sk = x25519_elligator2::StaticSecret::random_from_rng(&mut rng);
+        let rp: Option<x25519_elligator2::PublicRepresentative> = (&sk).into();
         let repres = match rp {
             Some(r) => r,
             None => {
@@ -277,9 +277,9 @@ fn about_half() -> Result<()> {
             }
         };
 
-        let pk = curve25519::PublicKey::from(&sk);
+        let pk = x25519_elligator2::PublicKey::from(&sk);
 
-        let decoded_pk = curve25519::PublicKey::from(&repres);
+        let decoded_pk = x25519_elligator2::PublicKey::from(&repres);
         if hex::encode(pk) != hex::encode(decoded_pk) {
             not_match += 1;
             continue;
@@ -303,9 +303,9 @@ fn keypair() -> Result<()> {
         let kp = Obfs4NtorSecretKey::generate_for_test(&mut rng);
 
         let pk = kp.pk.pk.to_bytes();
-        let repres: Option<curve25519::PublicRepresentative> = (&kp.sk).into();
+        let repres: Option<x25519_elligator2::PublicRepresentative> = (&kp.sk).into();
 
-        let pubkey = curve25519::PublicKey::from(&repres.unwrap());
+        let pubkey = x25519_elligator2::PublicKey::from(&repres.unwrap());
         assert_eq!(hex::encode(pk), hex::encode(pubkey.to_bytes()));
     }
     Ok(())

crates/obfs4/src/handshake/mod.rs

@@ -3,7 +3,7 @@
 use crate::{
     common::{
         ct,
-        curve25519::{EphemeralSecret, PublicKey, Representable, SharedSecret, StaticSecret},
+        x25519_elligator2::{EphemeralSecret, PublicKey, Keys, SharedSecret, StaticSecret},
         kdf::{Kdf, Ntor1Kdf},
         ntor_arti::{
             AuxDataReply, ClientHandshake, KeyGenerator, RelayHandshakeError, RelayHandshakeResult,
@@ -185,7 +185,7 @@ impl Obfs4NtorSecretKey {
 
     /// Construct a new ['Obfs4NtorSecretKey'] from a CSPRNG.
     pub(crate) fn getrandom() -> Self {
-        let sk = Representable::random_static();
+        let sk = Keys::random_static();
         let mut id = [0_u8; NODE_ID_LENGTH];
         getrandom::getrandom(&mut id).expect("internal randomness error");
         Self::new(sk, RsaIdentity::from(id))
@@ -198,7 +198,7 @@ impl Obfs4NtorSecretKey {
         // Random bytes will work for testing, but aren't necessarily actually a valid id.
         rng.fill_bytes(&mut id);
 
-        let sk = Representable::static_from_rng(rng);
+        let sk = Keys::static_from_rng(rng);
 
         let pk = Obfs4NtorPublicKey {
             pk: (&sk).into(),

crates/obfs4/src/lib.rs

@@ -50,7 +50,7 @@ pub mod dev {
     #[cfg(test)]
     mod test {
         use super::*;
-        use crate::common::curve25519::StaticSecret;
+        use crate::common::x25519_elligator2::StaticSecret;
         use crate::constants::*;
         use crate::handshake::Obfs4NtorSecretKey;
         use crate::{ClientBuilder, ServerBuilder};

crates/obfs4/src/server.rs

@@ -5,7 +5,7 @@ use crate::{
     client::ClientBuilder,
     common::{
         colorize,
-        curve25519::{PublicKey, StaticSecret},
+        x25519_elligator2::{PublicKey, StaticSecret},
         drbg,
         replay_filter::{self, ReplayFilter},
         HmacSha256,