refactor: minor code organization improvements

Cargo.toml

@@ -33,32 +33,29 @@ harness = false
 
 [features]
 default = ["std"]
-executable = ["dep:clap", "dep:rand_utils", "std"]
-serde = ["dep:serde", "serde?/alloc", "winter_math/serde"]
+executable = ["dep:clap", "dep:rand-utils", "std"]
+serde = ["dep:serde", "serde?/alloc", "winter-math/serde"]
 std = [
     "blake3/std",
     "dep:cc",
-    "winter_crypto/std",
-    "winter_math/std",
-    "winter_utils/std",
+    "winter-crypto/std",
+    "winter-math/std",
+    "winter-utils/std",
     "rand/std",
 ]
 
 [dependencies]
 blake3 = { version = "1.5", default-features = false }
-clap = { version = "4.5", features = ["derive"], optional = true }
-getrandom = { version = "0.2", features = ["js"] }
+clap = { version = "4.5", optional = true, features = ["derive"] }
 num = { version = "0.4", default-features = false, features = ["alloc"] }
 num-complex = { version = "0.4.4", default-features = false }
-rand = { version = "0.8", default-features = false, features = ["getrandom"] }
-rand_utils = { version = "0.8", package = "winter-rand-utils", optional = true }
-serde = { version = "1.0", features = [
-    "derive",
-], default-features = false, optional = true }
+rand = { version = "0.8", default-features = false }
+rand-utils = { version = "0.8", package = "winter-rand-utils", optional = true }
+serde = { version = "1.0", default-features = false, optional = true, features = ["derive"] }
 sha3 = { version = "0.10", default-features = false }
-winter_crypto = { version = "0.8", package = "winter-crypto", default-features = false }
-winter_math = { version = "0.8", package = "winter-math", default-features = false }
-winter_utils = { version = "0.8", package = "winter-utils", default-features = false }
+winter-crypto = { version = "0.8", default-features = false }
+winter-math = { version = "0.8", default-features = false }
+winter-utils = { version = "0.8", default-features = false }
 
 [dev-dependencies]
 criterion = { version = "0.5", features = ["html_reports"] }
@@ -68,5 +65,5 @@ rand_utils = { version = "0.8", package = "winter-rand-utils" }
 seq-macro = { version = "0.3" }
 
 [build-dependencies]
-cc = { version = "1.0", features = ["parallel"], optional = true }
+cc = { version = "1.0", optional = true, features = ["parallel"] }
 glob = "0.3"

src/dsa/rpo_falcon512/keys/mod.rs

@@ -1,7 +1,7 @@
 use super::{
     math::{FalconFelt, Polynomial},
     ByteReader, ByteWriter, Deserializable, DeserializationError, Felt, Serializable, Signature,
-    Word, MODULUS,
+    Word,
 };
 
 mod public_key;

src/dsa/rpo_falcon512/keys/public_key.rs

@@ -3,7 +3,7 @@ use crate::dsa::rpo_falcon512::FALCON_ENCODING_BITS;
 use super::{
     super::{Rpo256, LOG_N, N, PK_LEN},
     ByteReader, ByteWriter, Deserializable, DeserializationError, FalconFelt, Felt, Polynomial,
-    Serializable, Signature, Word, MODULUS,
+    Serializable, Signature, Word,
 };
 use alloc::string::ToString;
 use core::ops::Deref;
@@ -117,12 +117,13 @@ impl Deserializable for PubKeyPoly {
             if acc_len >= FALCON_ENCODING_BITS {
                 acc_len -= FALCON_ENCODING_BITS;
                 let w = (acc >> acc_len) & 0x3FFF;
-                if let Ok(value) = w.try_into() {
-                    output[output_idx] = FalconFelt::new(value);
-                    output_idx += 1;
-                } else {
-                    return Err(DeserializationError::InvalidValue(format!("Failed to decode public key: coefficient {w} is greater than or equal to the field modulus {MODULUS}")));
-                }
+                let element = w.try_into().map_err(|err| {
+                    DeserializationError::InvalidValue(format!(
+                        "Failed to decode public key: {err}"
+                    ))
+                })?;
+                output[output_idx] = element;
+                output_idx += 1;
             }
         }
 

src/dsa/rpo_falcon512/keys/secret_key.rs

@@ -176,6 +176,7 @@ impl SecretKey {
 
                 break [-s0, s1];
             };
+
             let s1 = bold_s[0].ifft();
             let s2 = bold_s[1].ifft();
             let s1_coef: [i16; N] = s1

src/dsa/rpo_falcon512/math/field.rs

@@ -1,5 +1,5 @@
 use super::{fft::CyclotomicFourier, Inverse, MODULUS};
-use alloc::string::{String, ToString};
+use alloc::string::String;
 use core::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Neg, Sub, SubAssign};
 use num::{One, Zero};
 
@@ -162,11 +162,11 @@ impl CyclotomicFourier for FalconFelt {
 impl TryFrom<u32> for FalconFelt {
     type Error = String;
 
-    fn try_from(x: u32) -> Result<Self, Self::Error> {
-        if let Ok(value) = x.try_into() {
-            Ok(FalconFelt::new(value))
+    fn try_from(value: u32) -> Result<Self, Self::Error> {
+        if value >= MODULUS as u32 {
+            Err(format!("value {value} is greater than or equal to the field modulus {MODULUS}"))
         } else {
-            Err("Value outside valid range for a field element".to_string())
+            Ok(FalconFelt::new(value as i16))
         }
     }
 }

src/dsa/rpo_falcon512/signature.rs

@@ -86,10 +86,9 @@ impl Signature {
     /// against the secret key matching the specified public key commitment.
     pub fn verify(&self, message: Word, pubkey_com: Word) -> bool {
         let c = hash_to_point_rpo256(message, &self.nonce);
-        let s1 = self.s1.clone();
-        let s2 = self.s2.clone();
-        let s1_fft = s1.fft();
-        let s2_fft = s2.fft();
+
+        let s1_fft = self.s1.fft();
+        let s2_fft = self.s2.fft();
         let c_fft = c.fft();
 
         // recover the public key polynomial using h = s2^(-1) * (c - s1)
@@ -100,7 +99,7 @@ impl Signature {
         let h_felt: Polynomial<Felt> = h.clone().into();
         let h_digest: Word = Rpo256::hash_elements(&h_felt.coefficients).into();
 
-        h_digest == pubkey_com && verify_helper(c, s2, h.into())
+        h_digest == pubkey_com && verify_helper(&c, &self.s2, &h.into())
     }
 }
 
@@ -301,7 +300,7 @@ impl Deserializable for SignaturePoly {
                 "Failed to decode signature: Non-zero unused bits in the last byte".to_string(),
             ));
         }
-        Ok(SignaturePoly::from(Polynomial::new(coefficients.to_vec())))
+        Ok(Polynomial::new(coefficients.to_vec()).into())
     }
 }
 
@@ -311,7 +310,7 @@ impl Deserializable for SignaturePoly {
 /// Takes the hash-to-point polynomial `c` of a message, the signature polynomial over
 /// the message `s2` and a public key polynomial and returns `true` is the signature is a valid
 /// signature for the given parameters, otherwise it returns `false`.
-fn verify_helper(c: Polynomial<FalconFelt>, s2: SignaturePoly, h: PubKeyPoly) -> bool {
+fn verify_helper(c: &Polynomial<FalconFelt>, s2: &SignaturePoly, h: &PubKeyPoly) -> bool {
     let h_fft = h.fft();
     let s2_fft = s2.fft();
     let c_fft = c.fft();