Crate pamoja_audit 

Tamper-evident audit logs for the pamoja SDK.

The health and cold-chain deployments this SDK targets need more than authentic readings; they need an authentic record of them. A vaccine fridge’s temperature history is only useful as evidence if no one can quietly edit out an excursion, drop an inconvenient reading, or reorder the log after the fact. This crate provides that record by chaining signed entries together:

• AuditLog - appends entries, each signed with a DeviceIdentity and linked by hash to the entry before it.
• Entry - one record: its payload, its index, the previous entry’s digest, and the signature, with a byte form for durable storage.
• Verifier and verify_chain - replay a stored log and confirm, against the device’s PublicIdentity, that every entry is in sequence, correctly chained, and authentically signed.

Because each entry commits to the previous one with a SHA-256 hash and an ed25519 signature, altering a payload, reordering entries, inserting a forgery, or dropping a record all break verification at the point of tampering. The crate is no_std and synchronous, so the same log can be written on a microcontroller and audited on a server.

Examples

use pamoja_audit::{verify_chain, AuditLog, Entry};
use pamoja_security::DeviceIdentity;

let device = DeviceIdentity::from_seed(&[9u8; 32]);
let public = device.public();

// Record two readings, persisting each entry's bytes as you would to an SD card.
let mut log = AuditLog::new(device);
let mut stored: Vec<Vec<u8>> = Vec::new();
for reading in [b"4.6C".as_slice(), b"4.9C".as_slice()] {
    stored.push(log.append(reading).to_bytes());
}

// An auditor rebuilds the chain from storage and verifies it.
let entries: Vec<Entry> = stored
    .iter()
    .map(|bytes| Entry::from_bytes(bytes))
    .collect::<pamoja_core::Result<_>>()
    .unwrap();
assert!(verify_chain(&public, &entries).is_ok());

Structs

AuditLog

Appends signed, hash-chained entries to a tamper-evident log.

Entry

One entry in a tamper-evident audit log.

Verifier

Verifies a log’s entries in sequence against the signer’s public identity.

Functions

verify_chain

Verifies a whole chain of entries from the start against public.