binius_examples/circuits/
sha512.rs

1// Copyright 2026 The Binius Developers
2// Copyright 2025 Irreducible Inc.
3use std::array;
4
5use anyhow::Result;
6use binius_circuits::{
7	fixed_byte_vec::ByteVec,
8	sha512::{sha512_fixed, sha512_varlen},
9};
10use binius_core::word::Word;
11use binius_frontend::{CircuitBuilder, Wire, WitnessFiller};
12use sha2::Digest;
13
14use super::utils::{self, HasherInstance, HasherMode, HasherParams};
15use crate::ExampleCircuit;
16
17pub struct Sha512Example {
18	circuit: Sha512Circuit,
19	mode: HasherMode,
20}
21
22/// Either the fixed-length (default) or variable-length SHA-512 circuit.
23enum Sha512Circuit {
24	/// Fixed-length gadget: message length is a compile-time constant.
25	Fixed {
26		message: Vec<Wire>,
27		digest: [Wire; 8],
28	},
29	/// Variable-length gadget: message length is a runtime witness.
30	Variable { message: ByteVec, digest: [Wire; 8] },
31}
32
33impl ExampleCircuit for Sha512Example {
34	type Params = HasherParams;
35	type Instance = HasherInstance;
36
37	fn build(params: HasherParams, builder: &mut CircuitBuilder) -> Result<Self> {
38		let mode = utils::resolve_hasher_mode(&params, "SHA-512", true)?;
39
40		let circuit = match mode {
41			// Fixed-length (default): message length is a compile-time constant.
42			HasherMode::Fixed { len_bytes } => {
43				let n_words = len_bytes.div_ceil(8);
44				let message: Vec<Wire> = (0..n_words).map(|_| builder.add_inout()).collect();
45				let computed_digest = sha512_fixed(builder, &message, len_bytes);
46				let digest: [Wire; 8] = array::from_fn(|_| builder.add_inout());
47				for i in 0..8 {
48					builder.assert_eq(format!("digest[{i}]"), computed_digest[i], digest[i]);
49				}
50				Sha512Circuit::Fixed { message, digest }
51			}
52			// Variable-length: message length is a runtime witness.
53			HasherMode::Variable { max_len_bytes } => {
54				let max_words = max_len_bytes.div_ceil(8);
55				let len_bytes = builder.add_inout();
56				let data: Vec<Wire> = (0..max_words).map(|_| builder.add_inout()).collect();
57				let byte_vec = ByteVec::new(data, len_bytes);
58				let digest: [Wire; 8] = array::from_fn(|_| builder.add_inout());
59				let computed_digest = sha512_varlen(builder, &byte_vec);
60				for i in 0..8 {
61					builder.assert_eq(format!("digest[{i}]"), computed_digest[i], digest[i]);
62				}
63				Sha512Circuit::Variable {
64					message: byte_vec,
65					digest,
66				}
67			}
68		};
69
70		Ok(Self { circuit, mode })
71	}
72
73	fn populate_witness(&self, instance: HasherInstance, w: &mut WitnessFiller<'_>) -> Result<()> {
74		let message = utils::resolve_hasher_message(&self.mode, &instance)?;
75		let digest = sha2::Sha512::digest(&message);
76
77		let digest_wires = match &self.circuit {
78			Sha512Circuit::Fixed {
79				message: message_wires,
80				digest,
81			} => {
82				// Message: 64-bit big-endian words, 8 bytes per wire.
83				for (wire, word) in message_wires
84					.iter()
85					.zip(utils::pack_bytes_u64words(&message, true))
86				{
87					w[*wire] = word;
88				}
89				digest
90			}
91			Sha512Circuit::Variable {
92				message: byte_vec,
93				digest,
94			} => {
95				byte_vec.populate_data(w, &message);
96				byte_vec.populate_len_bytes(w, message.len());
97				digest
98			}
99		};
100
101		// Digest: 8 x 64-bit big-endian words (identical for both branches).
102		for (i, chunk) in digest.chunks(8).enumerate() {
103			w[digest_wires[i]] = Word(u64::from_be_bytes(chunk.try_into().unwrap()));
104		}
105
106		Ok(())
107	}
108
109	fn param_summary(params: &Self::Params) -> Option<String> {
110		utils::hasher_param_summary(params)
111	}
112}
binius_examples/circuits/sha512.rs

binius_examples/circuits/
sha512.rs
