Overview

MCEL is a Merkle rooted, append-only event ledger designed for tamper-evident logging and audit. Records are hash-committed, blocks aggregate record commitments into a Merkle root, and checkpoints cryptographically bind block roots into a signed chain suitable for long-term verification.

Design Summary

The library exposes a storage abstraction through callbacks, allowing deployment over files, databases, object stores, or custom persistence layers. The ledger provides:

Deterministic record commitment and append
Merkle block sealing and root commitment
Signed checkpoint bundling and checkpoint chain verification
Inclusion proof generation and verification for audit exhibits

Storage Contract

MCEL uses a caller-supplied storage backend via callback functions. The backend must support querying size, reading, writing, and appending objects identified by location keys.

Security Notes

MCEL integrity depends on collision resistance of the hash function and unforgeability of the signature scheme used for checkpoints. Implementations should protect signing keys, enforce strict monotonic sequencing where required by policy, and ensure storage callbacks are atomic for append operations.

API Modules

Build Notes

MCEL is intended to be built as a static library. Applications should link MCEL and provide a storage backend implementation through the callback interface.

Cryptographic Dependencies

MCEL uses the QSC cryptographic library: The QSC Library

Conclusion

Author: John G. Underhill

Date: 2026-01-31