Add prover binary

Author: Dmytro Gordon

crates/core/src/constraint_system.rs

@@ -654,6 +654,12 @@ impl<'a> std::ops::Deref for ValuesData<'a> {
 	}
 }
 
+impl<'a> From<ValuesData<'a>> for Vec<Word> {
+	fn from(value: ValuesData<'a>) -> Self {
+		value.into_owned()
+	}
+}
+
 /// A zero-knowledge proof that can be serialized for cross-host verification.
 ///
 /// This structure contains the complete proof transcript generated by the prover,

crates/examples/Cargo.toml

@@ -30,3 +30,7 @@ sha2.workspace = true
 default = ["rayon"]
 perfetto = ["tracing-profile/perfetto"]
 rayon = ["binius-prover/rayon"]
+
+[[example]]
+name = "prover"
+path = "examples/prover.rs"

crates/examples/README.md

@@ -332,6 +332,35 @@ Look at these examples for reference:
 - `sha256.rs` - Shows parameter/instance separation, random data generation
 - `zklogin.rs` - Shows complex witness population with external data generation
 
+## Prover binary
+
+The `prover` example binary reads a constraint system and witnesses from disk and produces a serialized proof. This is useful for cross-host proof generation pipelines.
+
+Arguments:
+- `--cs-path PATH`: path to the constraint system binary
+- `--pub-witness-path PATH`: path to the public values binary (ValuesData)
+- `--non-pub-data-path PATH`: path to the non-public values binary (ValuesData)
+- `--proof-path PATH`: path to write the proof binary
+- `-l, --log-inv-rate N`: log of the inverse rate (default: 1)
+
+Usage:
+
+```bash
+# 1) Generate artifacts from an example circuit (e.g., sha256)
+cargo run --release --example sha256 -- save \
+    --cs-path out/sha256/cs.bin \
+    --pub-witness-path out/sha256/public.bin \
+    --non-pub-data-path out/sha256/non_public.bin
+
+# 2) Produce a proof from those files
+cargo run --release --example prover -- \
+    --cs-path out/sha256/cs.bin \
+    --pub-witness-path out/sha256/public.bin \
+    --non-pub-data-path out/sha256/non_public.bin \
+    --proof-path out/sha256/proof.bin \
+    --log-inv-rate 1
+```
+
 ## Tips
 
 1. **Keep it simple**: The main function should just create the CLI and run it

crates/examples/examples/prover.rs

@@ -0,0 +1,100 @@
+use std::{fs, path::PathBuf};
+
+use anyhow::{Context, Result};
+use binius_core::constraint_system::{ConstraintSystem, Proof, ValueVec, ValuesData};
+use binius_examples::setup;
+use binius_utils::serialization::{DeserializeBytes, SerializeBytes};
+use binius_verifier::{config::StdChallenger, transcript::ProverTranscript};
+use clap::Parser;
+
+/// Prover CLI: generate a proof from a serialized constraint system and witnesses.
+#[derive(Debug, Parser)]
+#[command(
+	name = "prover",
+	about = "Generate and save a proof from CS and witnesses"
+)]
+struct Args {
+	/// Path to the constraint system binary
+	#[arg(long = "cs-path")]
+	cs_path: PathBuf,
+
+	/// Path to the public values (ValuesData) binary
+	#[arg(long = "pub-witness-path")]
+	pub_witness_path: PathBuf,
+
+	/// Path to the non-public values (ValuesData) binary
+	#[arg(long = "non-pub-data-path")]
+	non_pub_data_path: PathBuf,
+
+	/// Path to write the proof binary
+	#[arg(long = "proof-path")]
+	proof_path: PathBuf,
+
+	/// Log of the inverse rate for the proof system
+	#[arg(short = 'l', long = "log-inv-rate", default_value_t = 1, value_parser = clap::value_parser!(u32).range(1..))]
+	log_inv_rate: u32,
+}
+
+fn main() -> Result<()> {
+	let _tracing_guard = tracing_profile::init_tracing().ok();
+	let args = Args::parse();
+
+	// Read and deserialize constraint system
+	let cs_bytes = fs::read(&args.cs_path).with_context(|| {
+		format!("Failed to read constraint system from {}", args.cs_path.display())
+	})?;
+	let cs = ConstraintSystem::deserialize(&mut cs_bytes.as_slice())
+		.context("Failed to deserialize ConstraintSystem")?;
+
+	// Read and deserialize public values
+	let pub_bytes = fs::read(&args.pub_witness_path).with_context(|| {
+		format!("Failed to read public values from {}", args.pub_witness_path.display())
+	})?;
+	let public = ValuesData::deserialize(&mut pub_bytes.as_slice())
+		.context("Failed to deserialize public ValuesData")?;
+
+	// Read and deserialize non-public values
+	let non_pub_bytes = fs::read(&args.non_pub_data_path).with_context(|| {
+		format!("Failed to read non-public values from {}", args.non_pub_data_path.display())
+	})?;
+	let non_public = ValuesData::deserialize(&mut non_pub_bytes.as_slice())
+		.context("Failed to deserialize non-public ValuesData")?;
+
+	// Reconstruct the full ValueVec
+	// Take ownership of the underlying vectors without extra copies
+	let public: Vec<_> = public.into();
+	let non_public: Vec<_> = non_public.into();
+	let witness = ValueVec::new_from_data(cs.value_vec_layout.clone(), public, non_public)
+		.context("Failed to reconstruct ValueVec from provided values")?;
+
+	// Setup prover (verifier is not used here)
+	let (_verifier, prover) = setup(cs, args.log_inv_rate as usize)?;
+
+	// Prove
+	let mut prover_transcript = ProverTranscript::new(StdChallenger::default());
+	prover
+		.prove(witness, &mut prover_transcript)
+		.context("Proving failed")?;
+	let transcript = prover_transcript.finalize();
+
+	// Wrap into serializable Proof with a stable challenger type identifier.
+	// NOTE: Avoid std::any::type_name for cross-platform stability; use a constant instead.
+	let proof = Proof::owned(transcript, "HasherChallenger<Sha256>".to_string());
+
+	// Serialize and save the proof
+	if let Some(parent) = args.proof_path.parent()
+		&& !parent.as_os_str().is_empty()
+	{
+		fs::create_dir_all(parent)
+			.with_context(|| format!("Failed to create parent directory {}", parent.display()))?;
+	}
+	let mut buf = Vec::new();
+	proof
+		.serialize(&mut buf)
+		.context("Failed to serialize proof")?;
+	fs::write(&args.proof_path, &buf)
+		.with_context(|| format!("Failed to write proof to {}", args.proof_path.display()))?;
+
+	eprintln!("Saved proof to {} ({} bytes)", args.proof_path.display(), buf.len());
+	Ok(())
+}