feat: implement pure-Rust keygen and signing for RpoFalcon512 (#285)

.gitmodules

@@ -1,3 +0,0 @@
-[submodule "PQClean"]
-	path = PQClean
-	url = https://github.com/PQClean/PQClean.git

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## 0.9.0 (TBD)
 
-* [BREAKING] Removed deprecated re-exports from liballoc/libstd.
+* [BREAKING] Removed deprecated re-exports from liballoc/libstd (#290).
+* [BREAKING] Refactored RpoFalcon512 signature to work with pure Rust (#285).
 
 # 0.8.4 (2024-03-17)
 

Cargo.toml

@@ -33,33 +33,40 @@ 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",
+    "rand/std",
+    "rand/std_rng",
+    "winter-crypto/std",
+    "winter-math/std",
+    "winter-utils/std",
 ]
 
 [dependencies]
 blake3 = { version = "1.5", default-features = false }
-clap = { version = "4.5", features = ["derive"], optional = true }
-rand_utils = { version = "0.8", package = "winter-rand-utils", optional = true }
-serde = { version = "1.0", features = [
-    "derive",
-], default-features = false, optional = true }
-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 }
+clap = { version = "4.5", optional = true, features = ["derive"] }
+num = { version = "0.4", default-features = false, features = ["alloc", "libm"] }
+num-complex = { version = "0.4.4", default-features = false }
+rand = { version = "0.8", default-features = false }
+rand_core = { version = "0.6", 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", default-features = false }
+winter-math = { version = "0.8", default-features = false }
+winter-utils = { version = "0.8", default-features = false }
 
 [dev-dependencies]
-seq-macro = { version = "0.3" }
 criterion = { version = "0.5", features = ["html_reports"] }
+getrandom = { version = "0.2", features = ["js"] }
+hex = { version = "0.4", default-features = false, features = ["alloc"] }
 proptest = "1.4"
 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"

README.md

@@ -33,7 +33,7 @@ The module also contains additional supporting components such as `NodeIndex`, `
 
 * `RPO Falcon512`: a variant of the [Falcon](https://falcon-sign.info/) signature scheme. This variant differs from the standard in that instead of using SHAKE256 hash function in the *hash-to-point* algorithm we use RPO256. This makes the signature more efficient to verify in Miden VM.
 
-For the above signatures, key generation and signing is available only in the `std` context (see [crate features](#crate-features) below), while signature verification is available in `no_std` context as well.
+For the above signatures, key generation, signing, and signature verification are available for both `std` and `no_std` contexts (see [crate features](#crate-features) below). However, in `no_std` context, the user is responsible for supplying the key generation and signing procedures with a random number generator.
 
 ## Pseudo-Random Element Generator
 [Pseudo random element generator module](./src/rand/) provides a set of traits and data structures that facilitate generating pseudo-random elements in the context of Miden VM and Miden rollup. The module currently includes:

build.rs

@@ -1,39 +1,8 @@
 fn main() {
-    #[cfg(feature = "std")]
-    compile_rpo_falcon();
-
     #[cfg(target_feature = "sve")]
     compile_arch_arm64_sve();
 }
 
-#[cfg(feature = "std")]
-fn compile_rpo_falcon() {
-    use std::path::PathBuf;
-
-    const RPO_FALCON_PATH: &str = "src/dsa/rpo_falcon512/falcon_c";
-
-    println!("cargo:rerun-if-changed={RPO_FALCON_PATH}/falcon.h");
-    println!("cargo:rerun-if-changed={RPO_FALCON_PATH}/falcon.c");
-    println!("cargo:rerun-if-changed={RPO_FALCON_PATH}/rpo.h");
-    println!("cargo:rerun-if-changed={RPO_FALCON_PATH}/rpo.c");
-
-    let target_dir: PathBuf = ["PQClean", "crypto_sign", "falcon-512", "clean"].iter().collect();
-    let common_dir: PathBuf = ["PQClean", "common"].iter().collect();
-
-    let scheme_files = glob::glob(target_dir.join("*.c").to_str().unwrap()).unwrap();
-    let common_files = glob::glob(common_dir.join("*.c").to_str().unwrap()).unwrap();
-
-    cc::Build::new()
-        .include(&common_dir)
-        .include(target_dir)
-        .files(scheme_files.into_iter().map(|p| p.unwrap().to_string_lossy().into_owned()))
-        .files(common_files.into_iter().map(|p| p.unwrap().to_string_lossy().into_owned()))
-        .file(format!("{RPO_FALCON_PATH}/falcon.c"))
-        .file(format!("{RPO_FALCON_PATH}/rpo.c"))
-        .flag("-O3")
-        .compile("rpo_falcon512");
-}
-
 #[cfg(target_feature = "sve")]
 fn compile_arch_arm64_sve() {
     const RPO_SVE_PATH: &str = "arch/arm64-sve/rpo";