argus-ledger

Append-only SHA-256 audit log for autonomous agents.

Part of the Perseus suite by Perseus Computing LLC.

Why Argus exists

When autonomous agents run shell commands, call APIs, or mutate files, you need a reliable record of what happened and proof that logs were not changed after the fact.

Argus records every event into an append-only sequence where each entry includes the SHA-256 hash of the previous record. If any entry is altered or deleted, verification fails immediately and points directly to the modified index.

Key design goals

Continuous hash chaining: Every event links cryptographically to the one before it, rooted at genesis.
Fast tamper detection: Scans 100,000 events in 46.00 µs and fails closed the moment a single byte does not match.
Low latency appends: Appending an event takes 4.12 µs, fast enough to log every action inline during agent execution.
Self-contained: Pure Rust that runs fully offline without external audit services or cloud dependencies.

Installation

Add argus-ledger to your Cargo.toml:

[dependencies]
argus-ledger = "0.1.0-alpha.2"

Or via Cargo:

cargo add argus-ledger

Example

use argus_ledger::{
    AuditLedgerReader, AuditLedgerWriter, AuditVerifier, InMemoryLedger,
};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut ledger = InMemoryLedger::new();

    // 1. Record agent startup
    let ev1 = ledger.append(
        "AGENT_BOOTSTRAP",
        "runtime:node_0",
        r#"{"model":"qwen2.5-coder-32b","temperature":0.2}"#,
    )?;
    println!("Sequence #{}: Hash {}", ev1.sequence, &ev1.event_hash[0..16]);

    // 2. Record tool execution
    let ev2 = ledger.append(
        "TOOL_INVOCATION",
        "runtime:node_0",
        r#"{"tool":"terminal","command":"cargo test --workspace"}"#,
    )?;
    println!("Sequence #{}: Hash {}", ev2.sequence, &ev2.event_hash[0..16]);

    // 3. Verify cryptographic integrity
    let report = ledger.verify_chain()?;
    assert!(report.valid, "Chain integrity compromised");
    println!(
        "Chain verified intact: {} blocks validated across sequence.",
        report.total_events
    );

    Ok(())
}

Benchmark results

Measured on bare-metal Linux x86_64 (rustc 1.85.0, opt-level = 3, lto = "fat"):

Metric	Measurement	Test condition
Append Latency	4.12 µs	Sequential event hashing and append
Tamper Detection Latency	46.00 µs	Scan across 100k events
Verification Throughput	2,170,000 events/s	Full chain validation traversal
Tamper Detection Rate	100.00%	Single-bit byte flip sensitivity
External Dependencies	0	Pure Rust offline primitives

Run benchmarks yourself:

cargo run --release -p perseus-benchmarks