CodeSampleX

Sample

rand_chacha 0.9.0: rand_chacha

Verified sample for cargo rand_chacha 0.9.0: rand_chacha. The contract ran on rust 1 · linux alpine/x64 · docker and passed: assert ChaCha20Rng::from_seed…

sha256:37ce1ea0ccaff1e7f5cc7b77de979df5bc27db7d51db1d3f964496bc83968291

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
1
Signing keys that built it
1
Declared environment linux · alpine · musl x64 cargo

Verification-run environments

Environment Contract Stages Run
rust 1 · linux alpine/x64 · docker ed25519:c1973797be207ac4 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · cargo@1rust:1-alpine@sha256:a10e64dd139b…		 2026-10-10

Case

HOW
Goal
verify rand_chacha in pkg:cargo/rand_chacha@0.9.0
Packages
Symbols
  • rand_chacha
Created
2026-10-10T15:49:42Z

Contract

  1. assert ChaCha20Rng::from_seed produces deterministic output matching ChaCha20 reference vector
  2. assert ChaCha20Rng::set_stream and set_word_pos control stream and offset positions
  3. assert ChaCha20Rng::fill_bytes populates destination slice via RngCore
  4. assert ChaCha12Rng and ChaCha8Rng construct from u64 seed and generate random u64 values
  5. assert ChaChaRng is an alias of ChaCha20Rng with identical behavior

Files

  • Cargo.lock
  • Cargo.toml
  • PROMPT.md
  • csx.json
  • spec.json
  • src/lib.rs
  • test/contract.rs

Download the source artifact (tar.gz)

Source

Cargo.lock
# This file is automatically @generated by Cargo.
# It is not intended for manual editing.
version = 4

[[package]]
name = "cfg-if"
version = "1.0.5"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "4e7648175b45a9a48536d676f68d918270699102aa8dab5496df06904c914600"

[[package]]
name = "getrandom"
version = "0.3.4"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "899def5c37c4fd7b2664648c28120ecec138e4d395b459e5ca34f9cce2dd77fd"
dependencies = [
 "cfg-if",
 "libc",
 "r-efi",
 "wasip2",
]

[[package]]
name = "libc"
version = "0.2.189"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "3eaf3ede3fee6db1a4c2ee091bf8a8b4dccdc6d17f656fb07896ee72867612f2"

[[package]]
name = "ppv-lite86"
version = "0.2.21"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "85eae3c4ed2f50dcfe72643da4befc30deadb458a9b590d720cde2f2b1e97da9"
dependencies = [
 "zerocopy",
]

[[package]]
name = "proc-macro2"
version = "1.0.107"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "985e7ec9bb745e6ce6535b544d84d6cd6f7ad8bd711c398938ae983b91a766d9"
dependencies = [
 "unicode-ident",
]

[[package]]
name = "quote"
version = "1.0.47"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "1fbf4db142a473a8d80c26bbf18454ed458bf8d26c8219c331daecfdbd079001"
dependencies = [
 "proc-macro2",
]

[[package]]
name = "r-efi"
version = "5.3.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"

[[package]]
name = "rand_chacha"
version = "0.9.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "d3022b5f1df60f26e1ffddd6c66e8aa15de382ae63b3a0c1bfc0e4d3e3f325cb"
dependencies = [
 "ppv-lite86",
 "rand_core",
]

[[package]]
name = "rand_core"
version = "0.9.5"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "76afc826de14238e6e8c374ddcc1fa19e374fd8dd986b0d2af0d02377261d83c"
dependencies = [
 "getrandom",
]

[[package]]
name = "sample-rand-chacha"
version = "0.1.0"
dependencies = [
 "rand_chacha",
]

[[package]]
name = "syn"
version = "2.0.119"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "872831b642d1a07999a962a351ed35b955ea2cfc8f3862091e2a240a84f17297"
dependencies = [
 "proc-macro2",
 "quote",
 "unicode-ident",
]

[[package]]
name = "unicode-ident"
version = "1.0.26"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "d245f478577f809a851594d02313b640fb437e0bb33866753cff937863096954"

[[package]]
name = "wasip2"
version = "1.0.4+wasi-0.2.12"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "b67efb37e106e55ce722a510d6b5f9c17f083e5fc79afc2badeb12cc313d9487"
dependencies = [
 "wit-bindgen",
]

[[package]]
name = "wit-bindgen"
version = "0.57.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "1ebf944e87a7c253233ad6766e082e3cd714b5d03812acc24c318f549614536e"

[[package]]
name = "zerocopy"
version = "0.8.57"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "d35102a9f36d089ccae9e4c6802bc118be4487b80aaffc0ab4e0cf5ce92d2873"
dependencies = [
 "zerocopy-derive",
]

[[package]]
name = "zerocopy-derive"
version = "0.8.57"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "146c01f5ab44258da43cf276c74a2763db2ff3969c9c652c3f2de07041d0b2bc"
dependencies = [
 "proc-macro2",
 "quote",
 "syn",
]
Cargo.toml
[package]
name = "sample-rand-chacha"
version = "0.1.0"
edition = "2021"
publish = false

[dependencies]
rand_chacha = "=0.9.0"

[[bin]]
name = "contract"
path = "test/contract.rs"
PROMPT.md
Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify rand_chacha in pkg:cargo/rand_chacha@0.9.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:cargo/rand_chacha@0.9.0
Demonstrate these symbols/APIs:
  - rand_chacha

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.
csx.json
{"case":{"caseId":"case:sha256:e6bca6d1e3a2b1da22fa733813c824b02bf84e7cc6b9f6ac4939a69124f5e398","contract":["assert ChaCha20Rng::from_seed produces deterministic output matching ChaCha20 reference vector","assert ChaCha20Rng::set_stream and set_word_pos control stream and offset positions","assert ChaCha20Rng::fill_bytes populates destination slice via RngCore","assert ChaCha12Rng and ChaCha8Rng construct from u64 seed and generate random u64 values","assert ChaChaRng is an alias of ChaCha20Rng with identical behavior"],"goal":"verify rand_chacha in pkg:cargo/rand_chacha@0.9.0","kind":"HOW","packages":["pkg:cargo/rand_chacha@0.9.0"],"schemaVersion":1,"symbols":["rand_chacha"]},"contractCommand":["cargo","run","--offline"],"environment":{"arch":"x64","distro":"alpine","ecosystem":"cargo","libc":"musl","os":"linux","packageManager":"cargo","schemaVersion":1},"license":"MIT-0","packages":["pkg:cargo/rand_chacha@0.9.0"],"schemaVersion":1,"subject":"pkg:cargo/rand_chacha@0.9.0","symbols":["rand_chacha"],"verifierAdapter":"cargo@1"}
spec.json
{
  "schemaVersion": 1,
  "goal": "verify rand_chacha in pkg:cargo/rand_chacha@0.9.0",
  "kind": "HOW",
  "packages": [
    "pkg:cargo/rand_chacha@0.9.0"
  ],
  "symbols": [
    "rand_chacha"
  ]
}
src/lib.rs
//! Clean-room verification sample for rand_chacha.

pub use rand_chacha::*;
test/contract.rs
use rand_chacha::rand_core::{RngCore, SeedableRng};
use rand_chacha::{ChaCha12Rng, ChaCha20Rng, ChaCha8Rng, ChaChaRng};

fn main() {
    // 1. Deterministic generation with ChaCha20Rng from a 32-byte seed
    let seed = [0u8; 32];
    let mut rng20 = ChaCha20Rng::from_seed(seed);
    assert_eq!(rng20.get_seed(), seed);
    let val1 = rng20.next_u32();
    assert_eq!(val1, 0xade0b876, "ChaCha20 first word must match reference vector");

    // 2. Stream and word position control
    rng20.set_stream(100);
    assert_eq!(rng20.get_stream(), 100);
    rng20.set_word_pos(32);
    assert_eq!(rng20.get_word_pos(), 32);

    // 3. Buffer filling via RngCore::fill_bytes
    let mut buf = [0u8; 16];
    rng20.fill_bytes(&mut buf);
    assert_ne!(buf, [0u8; 16], "fill_bytes should populate non-zero random bytes");

    // 4. ChaCha12Rng and ChaCha8Rng seeding and u64 generation
    let mut rng12 = ChaCha12Rng::seed_from_u64(999);
    let val12 = rng12.next_u64();
    assert_ne!(val12, 0);

    let mut rng8 = ChaCha8Rng::seed_from_u64(999);
    let val8 = rng8.next_u64();
    assert_ne!(val8, 0);

    // 5. Verify ChaChaRng type alias equivalence to ChaCha20Rng
    let mut alias_rng: ChaChaRng = ChaChaRng::from_seed(seed);
    assert_eq!(alias_rng.next_u32(), 0xade0b876);

    println!("All rand_chacha contract assertions passed successfully.");
}

Origin Seeder

anonymous