Move SignableInput to clsag::Input

coins/monero/src/clsag/mod.rs

@@ -1,6 +1,8 @@
 use rand_core::{RngCore, CryptoRng};
 use ff::Field;
 
+use thiserror::Error;
+
 use curve25519_dalek::{
   constants::ED25519_BASEPOINT_TABLE,
   scalar::Scalar,
@@ -15,7 +17,6 @@ use monero::{
 
 use crate::{
   Commitment,
-  transaction::SignableInput,
   c_verify_clsag,
   random_scalar,
   hash_to_scalar,
@@ -27,11 +28,68 @@ mod multisig;
 #[cfg(feature = "multisig")]
 pub use multisig::Multisig;
 
+#[derive(Error, Debug)]
+pub enum Error {
+  #[error("internal error ({0})")]
+  InternalError(String),
+  #[error("invalid ring member (member {0}, ring size {1})")]
+  InvalidRingMember(u8, u8),
+  #[error("invalid commitment")]
+  InvalidCommitment
+}
+
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub struct Input {
+  pub image: EdwardsPoint,
+  // Ring, the index we're signing for, and the actual commitment behind it
+  pub ring: Vec<[EdwardsPoint; 2]>,
+  pub i: usize,
+  pub commitment: Commitment
+}
+
+impl Input {
+  pub fn new(
+    image: EdwardsPoint,
+    ring: Vec<[EdwardsPoint; 2]>,
+    i: u8,
+    commitment: Commitment
+) -> Result<Input, Error> {
+    let n = ring.len();
+    if n > u8::MAX.into() {
+      Err(Error::InternalError("max ring size in this library is u8 max".to_string()))?;
+    }
+    if i >= (n as u8) {
+      Err(Error::InvalidRingMember(i, n as u8))?;
+    }
+    let i: usize = i.into();
+
+    // Validate the commitment matches
+    if ring[i][1] != commitment.calculate() {
+      Err(Error::InvalidCommitment)?;
+    }
+
+    Ok(Input { image, ring, i, commitment })
+  }
+
+  #[cfg(feature = "multisig")]
+  pub fn context(&self) -> Vec<u8> {
+    let mut context = self.image.compress().to_bytes().to_vec();
+    for pair in &self.ring {
+      // Doesn't include mixins[i] as CLSAG doesn't care and won't be affected by it
+      context.extend(&pair[0].compress().to_bytes());
+      context.extend(&pair[1].compress().to_bytes());
+    }
+    context.extend(&u8::try_from(self.i).unwrap().to_le_bytes());
+    // Doesn't include commitment as the above ring + index includes the commitment
+    context
+  }
+}
+
 #[allow(non_snake_case)]
 pub(crate) fn sign_core<R: RngCore + CryptoRng>(
   rng: &mut R,
   msg: &[u8; 32],
-  input: &SignableInput,
+  input: &Input,
   mask: Scalar,
   A: EdwardsPoint,
   AH: EdwardsPoint
@@ -148,7 +206,7 @@ pub(crate) fn sign_core<R: RngCore + CryptoRng>(
 pub fn sign<R: RngCore + CryptoRng>(
   rng: &mut R,
   msg: [u8; 32],
-  inputs: &[(Scalar, SignableInput)],
+  inputs: &[(Scalar, Input)],
   sum_outputs: Scalar
 ) -> Option<Vec<(Clsag, EdwardsPoint)>> {
   if inputs.len() == 0 {

coins/monero/src/clsag/multisig.rs

@@ -19,7 +19,7 @@ use monero::util::ringct::{Key, Clsag};
 use crate::{
   hash_to_point,
   frost::{MultisigError, Ed25519, DLEqProof},
-  clsag::{SignableInput, sign_core, verify}
+  clsag::{Input, sign_core, verify}
 };
 
 #[allow(non_snake_case)]
@@ -40,7 +40,7 @@ pub struct Multisig {
   AH: dfg::EdwardsPoint,
 
   msg: [u8; 32],
-  input: SignableInput,
+  input: Input,
 
   interim: Option<ClsagSignInterim>
 }
@@ -49,7 +49,7 @@ impl Multisig {
   pub fn new<R: RngCore + CryptoRng + SeedableRng>(
     rng: &mut R,
     msg: [u8; 32],
-    input: SignableInput
+    input: Input
   ) -> Result<Multisig, MultisigError> {
     let mut seed = [0; 32];
     rng.fill_bytes(&mut seed);

coins/monero/src/transaction/mod.rs

@@ -35,12 +35,6 @@ mod mixins;
 
 #[derive(Error, Debug)]
 pub enum TransactionError {
-  #[error("internal error ({0})")]
-  InternalError(String),
-  #[error("invalid ring member (member {0}, ring size {1})")]
-  InvalidRingMember(u8, u8),
-  #[error("invalid commitment")]
-  InvalidCommitment,
   #[error("no inputs")]
   NoInputs,
   #[error("too many outputs")]
@@ -51,6 +45,8 @@ pub enum TransactionError {
   InvalidAddress,
   #[error("rpc error ({0})")]
   RpcError(RpcError),
+  #[error("clsag error ({0})")]
+  ClsagError(clsag::Error),
   #[error("invalid transaction ({0})")]
   InvalidTransaction(RpcError)
 }
@@ -122,55 +118,6 @@ pub fn scan_tx(tx: &Transaction, view: Scalar, spend: EdwardsPoint) -> Vec<Spend
   res
 }
 
-#[derive(Clone, PartialEq, Eq, Debug)]
-pub struct SignableInput {
-  pub(crate) image: EdwardsPoint,
-  mixins: Vec<u64>,
-  // Ring, the index we're signing for, and the actual commitment behind it
-  pub(crate) ring: Vec<[EdwardsPoint; 2]>,
-  pub(crate) i: usize,
-  pub(crate) commitment: Commitment
-}
-
-impl SignableInput {
-  pub fn new(
-    image: EdwardsPoint,
-    mixins: Vec<u64>,
-    ring: Vec<[EdwardsPoint; 2]>,
-    i: u8,
-    commitment: Commitment
-  ) -> Result<SignableInput, TransactionError> {
-    let n = ring.len();
-    if n > u8::MAX.into() {
-      Err(TransactionError::InternalError("max ring size in this library is u8 max".to_string()))?;
-    }
-    if i >= (n as u8) {
-      Err(TransactionError::InvalidRingMember(i, n as u8))?;
-    }
-    let i: usize = i.into();
-
-    // Validate the commitment matches
-    if ring[i][1] != commitment.calculate() {
-      Err(TransactionError::InvalidCommitment)?;
-    }
-
-    Ok(SignableInput { image, mixins, ring, i, commitment })
-  }
-
-  #[cfg(feature = "multisig")]
-  pub fn context(&self) -> Vec<u8> {
-    let mut context = self.image.compress().to_bytes().to_vec();
-    for pair in &self.ring {
-      // Doesn't include mixins[i] as CLSAG doesn't care and won't be affected by it
-      context.extend(&pair[0].compress().to_bytes());
-      context.extend(&pair[1].compress().to_bytes());
-    }
-    context.extend(&u8::try_from(self.i).unwrap().to_le_bytes());
-    // Doesn't include commitment as the above ring + index includes the commitment
-    context
-  }
-}
-
 #[allow(non_snake_case)]
 fn shared_key(s: Scalar, P: &EdwardsPoint, o: usize) -> Scalar {
   let mut shared = (s * P).mul_by_cofactor().compress().to_bytes().to_vec();
@@ -269,29 +216,30 @@ pub async fn send<R: RngCore + CryptoRng>(
   ));
 
   // Handle inputs
+  let mut mixins = Vec::with_capacity(inputs.len());
   let mut signable = Vec::with_capacity(inputs.len());
-  for input in inputs {
-    let (m, mixins) = mixins::select(
+  for (i, input) in inputs.iter().enumerate() {
+    let (m, mix) = mixins::select(
       rpc.get_o_indexes(input.tx).await.map_err(|e| TransactionError::RpcError(e))?[input.o]
     );
+    mixins.push(mix);
     signable.push((
       spend + input.key_offset,
-      SignableInput::new(
+      clsag::Input::new(
         key_image::generate(&(spend + input.key_offset)),
-        mixins.clone(),
-        rpc.get_ring(&mixins).await.map_err(|e| TransactionError::RpcError(e))?,
+        rpc.get_ring(&mixins[i]).await.map_err(|e| TransactionError::RpcError(e))?,
         m,
         input.commitment
-      )?
+    ).map_err(|e| TransactionError::ClsagError(e))?
     ));
   }
 
   let prefix = TransactionPrefix {
     version: VarInt(2),
     unlock_time: VarInt(0),
-    inputs: signable.iter().map(|input| TxIn::ToKey {
+    inputs: signable.iter().enumerate().map(|(i, input)| TxIn::ToKey {
       amount: VarInt(0),
-      key_offsets: mixins::offset(&input.1.mixins).iter().map(|x| VarInt(*x)).collect(),
+      key_offsets: mixins::offset(&mixins[i]).iter().map(|x| VarInt(*x)).collect(),
       k_image: KeyImage {
         image: Hash(input.1.image.compress().to_bytes())
       }

coins/monero/tests/clsag.rs

@@ -3,7 +3,7 @@ use rand_chacha::ChaCha12Rng;
 
 use curve25519_dalek::{constants::ED25519_BASEPOINT_TABLE, scalar::Scalar};
 
-use monero_serai::{random_scalar, Commitment, frost::MultisigError, key_image, clsag, transaction::SignableInput};
+use monero_serai::{random_scalar, Commitment, frost::MultisigError, key_image, clsag};
 
 #[cfg(feature = "multisig")]
 use ::frost::sign;
@@ -47,9 +47,8 @@ fn test_single() {
     msg,
     &vec![(
       secrets[0],
-      SignableInput::new(
+      clsag::Input::new(
         image,
-        [0; RING_LEN as usize].to_vec(),
         ring.clone(),
         RING_INDEX,
         Commitment::new(secrets[1], AMOUNT)
@@ -113,7 +112,7 @@ fn test_multisig() -> Result<(), MultisigError> {
           clsag::Multisig::new(
             &mut ChaCha12Rng::seed_from_u64(1),
             msg,
-            SignableInput::new(image, vec![], ring.clone(), RING_INDEX, Commitment::new(randomness, AMOUNT)).unwrap()
+            clsag::Input::new(image, ring.clone(), RING_INDEX, Commitment::new(randomness, AMOUNT)).unwrap()
           ).unwrap(),
           keys[i - 1].clone(),
           &(1 ..= t).collect::<Vec<usize>>()