Move ElgamalRistretto255Choice to a module

Author: stanislav-tkach

rust/catalyst-contest/src/choices.rs

@@ -3,6 +3,8 @@
 use cbork_utils::decode_helper::decode_array_len;
 use minicbor::{Decode, Decoder, Encode, Encoder, encode::Write};
 
+use crate::elgamal_ristretto255_choice::ElgamalRistretto255Choice;
+
 /// Voters Choices.
 ///
 /// The CDDL schema:
@@ -32,25 +34,6 @@ pub enum Choices {
     },
 }
 
-/// An elgamal encrypted ciphertext `(c1, c2)`.
-///
-/// The CDDL schema:
-/// ```cddl
-/// elgamal-ristretto255-encrypted-choice = [
-///     c1: elgamal-ristretto255-group-element
-///     c2: elgamal-ristretto255-group-element
-/// ]
-///
-/// elgamal-ristretto255-group-element = bytes .size 32
-/// ```
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
-pub struct ElgamalRistretto255Choice {
-    /// An individual Elgamal group element that composes the elgamal cipher text.
-    pub c1: [u8; 32],
-    /// An individual Elgamal group element that composes the elgamal cipher text.
-    pub c2: [u8; 32],
-}
-
 /// A universal encrypted row proof.
 ///
 /// The CDDL schema:
@@ -141,35 +124,6 @@ impl Encode<()> for Choices {
     }
 }
 
-impl Decode<'_, ()> for ElgamalRistretto255Choice {
-    fn decode(
-        d: &mut Decoder<'_>,
-        ctx: &mut (),
-    ) -> Result<Self, minicbor::decode::Error> {
-        let len = decode_array_len(d, "elgamal ristretto255 choice")?;
-        if len != 2 {
-            return Err(minicbor::decode::Error::message(format!(
-                "Unexpected elgamal ristretto255 choice array length: {len}, expected 2"
-            )));
-        }
-        let c1 = <[u8; 32]>::decode(d, ctx)?;
-        let c2 = <[u8; 32]>::decode(d, ctx)?;
-        Ok(ElgamalRistretto255Choice { c1, c2 })
-    }
-}
-
-impl Encode<()> for ElgamalRistretto255Choice {
-    fn encode<W: Write>(
-        &self,
-        e: &mut Encoder<W>,
-        ctx: &mut (),
-    ) -> Result<(), minicbor::encode::Error<W::Error>> {
-        e.array(2)?;
-        self.c1.encode(e, ctx)?;
-        self.c2.encode(e, ctx)
-    }
-}
-
 impl Decode<'_, ()> for RowProof {
     fn decode(
         d: &mut Decoder<'_>,
@@ -220,25 +174,6 @@ mod tests {
         assert_eq!(original, decoded);
     }
 
-    #[test]
-    fn elgamal_ristretto255_choice_roundtrip() {
-        let bytes = [
-            1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
-            25, 26, 27, 28, 29, 30, 31, 32,
-        ];
-        let original = ElgamalRistretto255Choice {
-            c1: bytes,
-            c2: bytes,
-        };
-        let mut buffer = Vec::new();
-        original
-            .encode(&mut Encoder::new(&mut buffer), &mut ())
-            .unwrap();
-        let decoded =
-            ElgamalRistretto255Choice::decode(&mut Decoder::new(&buffer), &mut ()).unwrap();
-        assert_eq!(original, decoded);
-    }
-
     #[test]
     fn row_proof_roundtrip() {
         let original = RowProof {};

rust/catalyst-contest/src/contest_ballot.rs

@@ -76,7 +76,7 @@ impl Encode<()> for ContentBallot {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::{ElgamalRistretto255Choice, EncryptedBlock, RowProof};
+    use crate::{EncryptedBlock, RowProof, elgamal_ristretto255_choice::ElgamalRistretto255Choice};
 
     #[test]
     fn roundtrip() {

rust/catalyst-contest/src/elgamal_ristretto255_choice.rs

@@ -0,0 +1,76 @@
+//! An elgamal encrypted ciphertext.
+
+use cbork_utils::decode_helper::decode_array_len;
+use minicbor::{Decode, Decoder, Encode, Encoder, encode::Write};
+
+/// An elgamal encrypted ciphertext `(c1, c2)`.
+///
+/// The CDDL schema:
+/// ```cddl
+/// elgamal-ristretto255-encrypted-choice = [
+///     c1: elgamal-ristretto255-group-element
+///     c2: elgamal-ristretto255-group-element
+/// ]
+///
+/// elgamal-ristretto255-group-element = bytes .size 32
+/// ```
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct ElgamalRistretto255Choice {
+    /// An individual Elgamal group element that composes the elgamal cipher text.
+    pub c1: [u8; 32],
+    /// An individual Elgamal group element that composes the elgamal cipher text.
+    pub c2: [u8; 32],
+}
+
+impl Decode<'_, ()> for ElgamalRistretto255Choice {
+    fn decode(
+        d: &mut Decoder<'_>,
+        ctx: &mut (),
+    ) -> Result<Self, minicbor::decode::Error> {
+        let len = decode_array_len(d, "elgamal ristretto255 choice")?;
+        if len != 2 {
+            return Err(minicbor::decode::Error::message(format!(
+                "Unexpected elgamal ristretto255 choice array length: {len}, expected 2"
+            )));
+        }
+        let c1 = <[u8; 32]>::decode(d, ctx)?;
+        let c2 = <[u8; 32]>::decode(d, ctx)?;
+        Ok(ElgamalRistretto255Choice { c1, c2 })
+    }
+}
+
+impl Encode<()> for ElgamalRistretto255Choice {
+    fn encode<W: Write>(
+        &self,
+        e: &mut Encoder<W>,
+        ctx: &mut (),
+    ) -> Result<(), minicbor::encode::Error<W::Error>> {
+        e.array(2)?;
+        self.c1.encode(e, ctx)?;
+        self.c2.encode(e, ctx)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn roundtrip() {
+        let bytes = [
+            1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
+            25, 26, 27, 28, 29, 30, 31, 32,
+        ];
+        let original = ElgamalRistretto255Choice {
+            c1: bytes,
+            c2: bytes,
+        };
+        let mut buffer = Vec::new();
+        original
+            .encode(&mut Encoder::new(&mut buffer), &mut ())
+            .unwrap();
+        let decoded =
+            ElgamalRistretto255Choice::decode(&mut Decoder::new(&buffer), &mut ()).unwrap();
+        assert_eq!(original, decoded);
+    }
+}

rust/catalyst-contest/src/lib.rs

@@ -10,13 +10,15 @@
 mod choices;
 mod column_proof;
 mod contest_ballot;
+mod elgamal_ristretto255_choice;
 mod encrypted_choices;
 mod matrix_proof;
 
 pub use crate::{
-    choices::{Choices, ElgamalRistretto255Choice, RowProof},
+    choices::{Choices, RowProof},
     column_proof::ColumnProof,
     contest_ballot::ContentBallot,
+    elgamal_ristretto255_choice::ElgamalRistretto255Choice,
     encrypted_choices::{EncryptedBlock, EncryptedChoices},
     matrix_proof::MatrixProof,
 };