refactor: move group-related functions into crate::group.

Author: mmaker

src/composition.rs

@@ -29,9 +29,9 @@ use crate::{
     errors::Error,
     fiat_shamir::Nizk,
     linear_relation::{CanonicalLinearRelation, LinearRelation},
-    serialization::{deserialize_scalars, serialize_scalars},
     traits::{SigmaProtocol, SigmaProtocolSimulator},
 };
+use crate::group::serialization::{deserialize_scalars, serialize_scalars};
 
 /// A protocol proving knowledge of a witness for a composition of linear relations.
 ///

src/group/mod.rs

@@ -0,0 +1,5 @@
+/// Implementation of multi-scalar multiplication (MSM) over scalars and points.
+pub mod msm;
+
+/// Implementation of batch serialization functions for scalars and points.
+pub mod serialization;

src/linear_relation/msm.rs renamed to src/group/msm.rs

@@ -50,16 +50,16 @@
 #![deny(unused_variables)]
 #![deny(unused_mut)]
 
+pub mod codec;
 pub mod composition;
 pub mod errors;
-pub mod fiat_shamir;
 pub mod linear_relation;
-pub mod schnorr_protocol;
-pub mod serialization;
 pub mod traits;
 
-pub mod codec;
-pub mod duplex_sponge;
+pub(crate) mod duplex_sponge;
+pub(crate) mod fiat_shamir;
+pub(crate) mod group;
+pub(crate) mod schnorr_protocol;
 
 #[cfg(test)]
 pub mod tests;

src/serialization.rs renamed to src/group/serialization.rs

@@ -8,7 +8,7 @@ use subtle::{Choice, ConstantTimeEq};
 
 use super::{GroupMap, GroupVar, LinearCombination, LinearRelation, ScalarTerm, ScalarVar};
 use crate::errors::{Error, InvalidInstance};
-use crate::linear_relation::msm::VariableMultiScalarMul;
+use crate::group::msm::VariableMultiScalarMul;
 
 // XXX. this definition is uncomfortably similar to LinearRelation, exception made for the weights.
 // It'd be nice to better compress potentially duplicated code.
@@ -258,7 +258,7 @@ impl<G: PrimeGroup> CanonicalLinearRelation<G> {
     /// ```
     pub fn from_label(data: &[u8]) -> Result<Self, Error> {
         use crate::errors::InvalidInstance;
-        use crate::serialization::group_elt_serialized_len;
+        use crate::group::serialization::group_elt_serialized_len;
 
         let mut offset = 0;
 

src/lib.rs

@@ -16,6 +16,7 @@ use group::prime::PrimeGroup;
 
 use crate::codec::Shake128DuplexSponge;
 use crate::errors::{Error, InvalidInstance};
+use crate::group::msm::VariableMultiScalarMul;
 use crate::Nizk;
 
 /// Implementations of conversion operations such as From and FromIterator for var and term types.
@@ -27,10 +28,6 @@ mod ops;
 mod canonical;
 pub use canonical::CanonicalLinearRelation;
 
-/// Implementation of multi-scalar multiplication (MSM) over scalars and points.
-mod msm;
-pub use msm::VariableMultiScalarMul;
-
 /// A wrapper representing an index for a scalar variable.
 ///
 /// Used to reference scalars in sparse linear combinations.

src/linear_relation/canonical.rs

@@ -5,13 +5,11 @@
 //! through a group morphism abstraction (see [Maurer09](https://crypto-test.ethz.ch/publications/files/Maurer09.pdf)).
 
 use crate::errors::Error;
-use crate::linear_relation::CanonicalLinearRelation;
-use crate::{
-    serialization::{
-        deserialize_elements, deserialize_scalars, serialize_elements, serialize_scalars,
-    },
-    traits::{SigmaProtocol, SigmaProtocolSimulator},
+use crate::group::serialization::{
+    deserialize_elements, deserialize_scalars, serialize_elements, serialize_scalars,
 };
+use crate::linear_relation::CanonicalLinearRelation;
+use crate::traits::{SigmaProtocol, SigmaProtocolSimulator};
 
 use ff::Field;
 use group::prime::PrimeGroup;

src/linear_relation/mod.rs

@@ -60,7 +60,7 @@ fn test_spec_testvectors() {
             .expect("Failed to parse statement");
 
         // Decode the witness from the test vector
-        let witness = crate::serialization::deserialize_scalars::<G>(
+        let witness = crate::group::serialization::deserialize_scalars::<G>(
             &vector.witness,
             parsed_instance.num_scalars,
         )

src/schnorr_protocol.rs

@@ -5,9 +5,9 @@ use rand::RngCore;
 
 use crate::codec::Shake128DuplexSponge;
 use crate::fiat_shamir::Nizk;
-use crate::linear_relation::{CanonicalLinearRelation, Sum};
+use crate::linear_relation::{CanonicalLinearRelation, LinearRelation, Sum};
 
-use crate::linear_relation::{LinearRelation, VariableMultiScalarMul};
+use crate::group::msm::VariableMultiScalarMul;
 
 /// LinearMap for knowledge of a discrete logarithm relative to a fixed basepoint.
 #[allow(non_snake_case)]
@@ -269,26 +269,13 @@ pub fn test_range<G: PrimeGroup, R: RngCore>(
         .copied()
         .collect::<Vec<_>>();
 
-    println!("test_range: witness length = {}", witness.len());
-
     instance.set_elements([(var_G, G), (var_H, H)]);
     instance.set_element(var_C, G * x + H * r);
     for i in 0..BITS {
         instance.set_element(var_Ds[i], G * b[i] + H * s[i]);
     }
-    assert!(
-        instance.canonical().is_ok(),
-        "{}",
-        instance.canonical().err().unwrap()
-    );
-
-    let canonical = instance.canonical().unwrap();
-    println!(
-        "test_range: relation has {} scalar variables",
-        canonical.num_scalars
-    );
 
-    (canonical, witness)
+    (instance.canonical().unwrap(), witness)
 }
 
 /// LinearMap for knowledge of an opening for use in a BBS commitment.