fix: update ffi api and readme

Cargo.toml

@@ -11,7 +11,7 @@ crate-type = ["staticlib"]
 [features]
 ffi = []
 include_rln_ffi = []
-default = []
+default = ["ffi"]
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 

README.md

@@ -13,24 +13,25 @@ Uses the [arkworks-rs](https://github.com/arkworks-rs/curves) suite of libraries
 Note: this scheme should be used with the fork of [circom-rln](https://github.com/rymnc/circom-rln-erc5564). 
 
 ```rust
-use erc_5564_bn254::{random_keypair, generate_stealth_commitment, generate_stealth_private_key};
+use erc_5564_rs::{StealthAddressOnCurve}; // can use bls12_381_impl or bls12_377_impl too
+use ark_bn254::Bn254;
 
 fn main() {
-    let (spending_key, spending_public_key) = random_keypair();
-    let (viewing_key, viewing_public_key) = random_keypair();
+    let (spending_key, spending_public_key) = Bn254::random_keypair();
+    let (viewing_key, viewing_public_key) = Bn254::random_keypair();
 
     // generate ephemeral keypair
-    let (ephemeral_private_key, ephemeral_public_key) = random_keypair();
+    let (ephemeral_private_key, ephemeral_public_key) = Bn254::random_keypair();
 
-    let (stealth_commitment, view_tag) = generate_stealth_commitment(viewing_public_key, spending_public_key, ephemeral_private_key);
+    let (stealth_commitment, view_tag) = Bn254::generate_stealth_commitment(viewing_public_key, spending_public_key, ephemeral_private_key);
 
-    let stealth_private_key_opt = generate_stealth_private_key(ephemeral_public_key, viewing_key, spending_key, view_tag);
+    let stealth_private_key_opt = Bn254::generate_stealth_private_key(ephemeral_public_key, viewing_key, spending_key, view_tag);
 
     if stealth_private_key_opt.is_none() {
         panic!("View tags did not match");
     }
 
-    let derived_commitment = derive_public_key(stealth_private_key_opt.unwrap());
+    let derived_commitment = Bn254::derive_public_key(stealth_private_key_opt.unwrap());
     assert_eq!(derived_commitment, stealth_commitment);
 }
 ```
@@ -43,6 +44,10 @@ fn main() {
 2. Testing
     `cargo test --release`
 
+## FFI Api
+
+The exposed FFI API only supports the bn254 curve at the moment. In the future, it will support all the curve implementations.
+
 ## Attribution
 
 - The original circuits for rln are located [here](https://github.com/Rate-Limting-Nullifier/circom-rln), by the PSE group

src/ffi.rs

@@ -2,11 +2,8 @@ use crate::ffi::CErrorCode::{
     NoError, SerializationErrorInvalidData, SerializationErrorIoError,
     SerializationErrorNotEnoughSpace, SerializationErrorUnexpectedFlags,
 };
-use crate::stealth_commitments::{
-    derive_public_key, generate_random_fr, generate_stealth_commitment,
-    generate_stealth_private_key, random_keypair,
-};
-use ark_bn254::{Fr, G1Projective};
+use crate::stealth_commitments::{StealthAddressOnCurve};
+use ark_bn254::{Bn254, Fr, G1Projective};
 use ark_serialize::{CanonicalDeserialize, CanonicalSerialize, SerializationError};
 use num_traits::Zero;
 use std::ops::Add;
@@ -193,7 +190,7 @@ impl TryInto<(G1Projective, u64)> for CStealthCommitment {
 
 #[no_mangle]
 pub extern "C" fn ffi_generate_random_fr() -> *mut CReturn<CFr> {
-    let res = match CFr::try_from(generate_random_fr()) {
+    let res = match CFr::try_from(Bn254::generate_random_fr()) {
         Ok(v) => CReturn {
             value: v,
             err_code: NoError,
@@ -237,7 +234,7 @@ pub extern "C" fn ffi_derive_public_key(private_key: *mut CFr) -> *mut CReturn<C
         }
     };
 
-    let res = match CG1Projective::try_from(derive_public_key(private_key)) {
+    let res = match CG1Projective::try_from(Bn254::derive_public_key(&private_key)) {
         Ok(v) => CReturn {
             value: v,
             err_code: NoError,
@@ -262,7 +259,7 @@ pub extern "C" fn drop_ffi_derive_public_key(ptr: *mut CReturn<CG1Projective>) {
 
 #[no_mangle]
 pub extern "C" fn ffi_random_keypair() -> *mut CReturn<CKeyPair> {
-    let (private_key, public_key) = random_keypair();
+    let (private_key, public_key) = Bn254::random_keypair();
     let private_key = match CFr::try_from(private_key) {
         Ok(v) => v,
         Err(err) => {
@@ -362,7 +359,7 @@ pub extern "C" fn ffi_generate_stealth_commitment(
             }))
         }
     };
-    let res = match CStealthCommitment::try_from(generate_stealth_commitment(
+    let res = match CStealthCommitment::try_from(Bn254::generate_stealth_commitment(
         viewing_public_key,
         spending_public_key,
         ephemeral_private_key,
@@ -463,7 +460,7 @@ pub extern "C" fn ffi_generate_stealth_private_key(
         }
     };
     let stealth_private_key_opt =
-        generate_stealth_private_key(ephemeral_public_key, spending_key, viewing_key, *view_tag);
+        Bn254::generate_stealth_private_key(ephemeral_public_key, spending_key, viewing_key, *view_tag);
     if stealth_private_key_opt.is_none() {
         return Box::into_raw(Box::new(CReturn {
             value: CFr::zero(),
@@ -497,7 +494,6 @@ pub extern "C" fn drop_ffi_generate_stealth_private_key(ptr: *mut CReturn<CFr>)
 mod tests {
 
     use super::*;
-    use crate::stealth_commitments::derive_public_key;
     use ark_ec::CurveGroup;
 
     #[test]
@@ -522,7 +518,7 @@ mod tests {
         assert!(public_key.into_affine().is_on_curve());
 
         // Check if the derived key matches the one generated from the original key
-        assert_eq!(derive_public_key(private_key), public_key);
+        assert_eq!(Bn254::derive_public_key(&private_key), public_key);
     }
 
     #[test]

src/lib.rs

@@ -2,6 +2,7 @@ mod stealth_commitments;
 
 mod bls12_381_impl;
 mod bn254_impl;
+mod bls12_377_impl;
+
 #[cfg(feature = "ffi")]
 mod ffi;
-mod bls12_377_impl;