Smash out MLSAG

coins/monero/ringct/mlsag/Cargo.toml

@@ -0,0 +1,45 @@
+[package]
+name = "monero-mlsag"
+version = "0.1.0"
+description = "The MLSAG linkable ring signature, as defined by the Monero protocol"
+license = "MIT"
+repository = "https://github.com/serai-dex/serai/tree/develop/coins/monero/ringct/mlsag"
+authors = ["Luke Parker <lukeparker5132@gmail.com>"]
+edition = "2021"
+rust-version = "1.79"
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+
+[lints]
+workspace = true
+
+[dependencies]
+std-shims = { path = "../../../../common/std-shims", version = "^0.1.1", default-features = false }
+
+thiserror = { version = "1", default-features = false, optional = true }
+
+zeroize = { version = "^1.5", default-features = false, features = ["zeroize_derive"] }
+
+# Cryptographic dependencies
+curve25519-dalek = { version = "4", default-features = false, features = ["alloc", "zeroize"] }
+
+# Other Monero dependencies
+monero-io = { path = "../../io", version = "0.1", default-features = false }
+monero-generators = { path = "../../generators", version = "0.4", default-features = false }
+monero-primitives = { path = "../../primitives", version = "0.1", default-features = false }
+
+[features]
+std = [
+  "std-shims/std",
+
+  "thiserror",
+
+  "zeroize/std",
+
+  "monero-io/std",
+  "monero-generators/std",
+  "monero-primitives/std",
+]
+default = ["std"]

coins/monero/ringct/mlsag/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2022-2024 Luke Parker
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

coins/monero/ringct/mlsag/README.md

@@ -0,0 +1,6 @@
+# Monero MLSAG
+
+The MLSAG linkable ring signature, as defined by the Monero protocol.
+
+This library is usable under no-std when the `std` feature (on by default) is
+disabled.

coins/monero/ringct/mlsag/src/lib.rs

@@ -1,3 +1,9 @@
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![doc = include_str!("../README.md")]
+#![deny(missing_docs)]
+#![cfg_attr(not(feature = "std"), no_std)]
+#![allow(non_snake_case)]
+
 use std_shims::{
   vec::Vec,
   io::{self, Read, Write},
@@ -7,9 +13,9 @@ use zeroize::Zeroize;
 
 use curve25519_dalek::{traits::IsIdentity, Scalar, EdwardsPoint};
 
-use monero_generators::H;
-
-use crate::{hash_to_scalar, ringct::hash_to_point, serialize::*};
+use monero_io::*;
+use monero_generators::{H, hash_to_point};
+use monero_primitives::keccak256_to_scalar;
 
 /// Errors when working with MLSAGs.
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
@@ -68,17 +74,17 @@ impl RingMatrix {
     RingMatrix::new(matrix)
   }
 
-  /// Iterate the members of the matrix.
+  /// Iterate over the members of the matrix.
   fn iter(&self) -> impl Iterator<Item = &[EdwardsPoint]> {
     self.matrix.iter().map(AsRef::as_ref)
   }
 
-  /// Returns the amount of members in the ring.
+  /// Get the amount of members in the ring.
   pub fn members(&self) -> usize {
     self.matrix.len()
   }
 
-  /// Returns the length of a ring member.
+  /// Get the length of a ring member.
   ///
   /// A ring member is a vector of points for which the signer knows all of the discrete logarithms
   /// of.
@@ -96,7 +102,7 @@ pub struct Mlsag {
 }
 
 impl Mlsag {
-  /// Write the MLSAG to a writer.
+  /// Write a MLSAG.
   pub fn write<W: Write>(&self, w: &mut W) -> io::Result<()> {
     for ss in &self.ss {
       write_raw_vec(write_scalar, ss, w)?;
@@ -104,7 +110,7 @@ impl Mlsag {
     write_scalar(&self.cc, w)
   }
 
-  /// Read the MLSAG from a reader.
+  /// Read a MLSAG.
   pub fn read<R: Read>(mixins: usize, ss_2_elements: usize, r: &mut R) -> io::Result<Mlsag> {
     Ok(Mlsag {
       ss: (0 .. mixins)
@@ -114,7 +120,7 @@ impl Mlsag {
     })
   }
 
-  /// Verify the MLSAG.
+  /// Verify a MLSAG.
   pub fn verify(
     &self,
     msg: &[u8; 32],
@@ -149,7 +155,8 @@ impl Mlsag {
         #[allow(non_snake_case)]
         let L = EdwardsPoint::vartime_double_scalar_mul_basepoint(&ci, ring_member_entry, s);
 
-        buf.extend_from_slice(ring_member_entry.compress().as_bytes());
+        let compressed_ring_member_entry = ring_member_entry.compress();
+        buf.extend_from_slice(compressed_ring_member_entry.as_bytes());
         buf.extend_from_slice(L.compress().as_bytes());
 
         // Not all dimensions need to be linkable, e.g. commitments, and only linkable layers need
@@ -160,12 +167,12 @@ impl Mlsag {
           }
 
           #[allow(non_snake_case)]
-          let R = (s * hash_to_point(ring_member_entry)) + (ci * ki);
+          let R = (s * hash_to_point(compressed_ring_member_entry.to_bytes())) + (ci * ki);
           buf.extend_from_slice(R.compress().as_bytes());
         }
       }
 
-      ci = hash_to_scalar(&buf);
+      ci = keccak256_to_scalar(&buf);
       // keep the msg in the buffer.
       buf.drain(msg.len() ..);
     }
@@ -190,7 +197,7 @@ pub struct AggregateRingMatrixBuilder {
 impl AggregateRingMatrixBuilder {
   /// Create a new AggregateRingMatrixBuilder.
   ///
-  /// Takes in the transaction's outputs; commitments and fee.
+  /// This takes in the transaction's outputs' commitments and fee used.
   pub fn new(commitments: &[EdwardsPoint], fee: u64) -> Self {
     AggregateRingMatrixBuilder {
       key_ring: vec![],