zclassic23
Copyright 2026 Rhett Creighton

This product is licensed under the Apache License, Version 2.0 (see
LICENSE file in the root of this source tree, or at
http://www.apache.org/licenses/LICENSE-2.0).

This product includes software originally developed by other projects,
redistributed here under their respective licenses. All original
copyright notices are preserved below as required by the Apache
License, Version 2.0, Section 4(d) and by the upstream licenses
themselves.

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Bitcoin Core — MIT License
Copyright (c) 2009-2019 The Bitcoin Core developers
Copyright (c) 2009-2019 Bitcoin Developers

  Script interpreter semantics (BIP-30 / BIP-34 / BIP-65 / BIP-66),
  Bloom filter design, compact-blocks protocol, and general Bitcoin
  consensus surface inherited via zcashd and zclassicd. All identifiable
  Bitcoin Core code paths have been re-implemented in C23 from scratch
  in zclassic23; the MIT copyright notice is preserved here because
  the semantics and test vectors originate with Bitcoin Core.

Repository: https://github.com/bitcoin/bitcoin
License:    https://github.com/bitcoin/bitcoin/blob/master/COPYING

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Zcash (zcashd) — MIT License
Copyright (c) 2016-2019 The Zcash developers

  Sapling and Sprout zk-SNARK designs, Equihash 200/9 proof-of-work,
  shielded-pool accounting rules, and nu-series network upgrade
  ordering. Consensus-critical semantics match zcashd bit-for-bit via
  the parity-diff service (see AGENT.md row P12.3).

Repository: https://github.com/zcash/zcash
License:    https://github.com/zcash/zcash/blob/master/COPYING

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ZClassic Community (zclassicd, legacy peer) — MIT License
Copyright (c) 2017-2021 The SoloPool.org Team
Copyright (c) 2021-2022 ZClassic Community

  Chain history, checkpoint schedule, network magic, and the reference
  behavior used by zclassic23's parity-diff service. zclassicd remains
  the canonical legacy peer for bootstrap.

Repository: https://github.com/ZclassicCommunity/zclassic
License:    https://github.com/ZclassicCommunity/zclassic/blob/master/COPYING

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VENDORED DEPENDENCIES

The following third-party components are distributed in source form
under vendor/ and retain their original licenses.

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Tor (modified fork with dynhost extension) — 3-Clause BSD License
Copyright (c) The Tor Project, Inc.

  Embedded Tor with in-process dynhost API for .onion hidden-service
  hosting. Fork: https://github.com/RhettCreighton/tor

Upstream:   https://gitlab.torproject.org/tpo/core/tor
License:    https://gitlab.torproject.org/tpo/core/tor/-/blob/main/LICENSE
Vendored:   vendor/tor/

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SQLite — Public Domain
  Canonical UTXO store, wallet keystore, block index, application state.

Upstream:   https://sqlite.org
License:    https://www.sqlite.org/copyright.html
Vendored:   vendor/ (amalgamation)

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secp256k1 — MIT License
Copyright (c) Pieter Wuille and contributors

  ECDSA curve operations for transparent-address cryptography.

Upstream:   https://github.com/bitcoin-core/secp256k1
Vendored:   vendor/

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LevelDB — BSD-3-Clause License
Copyright (c) The LevelDB Authors

  Legacy block-index read path (import-only; writes go through the
  SQLite canonical store).

Upstream:   https://github.com/google/leveldb
Vendored:   vendor/

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dcrdex — Blue Oak Model License 1.0.0
Copyright (c) The Decred Developers

  Cross-chain atomic swap HTLC script format (97-byte P2SH-wrapped
  contract). Used by the ZCL Atomic Swap Protocol (ZSWP).

Upstream:   https://github.com/decred/dcrdex
License:    https://blueoakcouncil.org/license/1.0.0
Vendored:   vendor/dcrdex/

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CONCEPT ATTRIBUTIONS (no code; architectural inspiration only)

zclassic23 adopts architectural concepts from the following projects
without incorporating their source code. The implementations in
zclassic23 are written in C23 from scratch and do not link against
the original projects. We credit them here because it is the right
thing to do. A per-concept breakdown with commit-level cross-references
is maintained in ATTRIBUTIONS.md.

  * Erigon (Ethereum execution client) — LGPL-3.0
      Staged-sync pipeline, ETL bulk-write framework, temporal DB
      interface, per-subsystem agents.md discipline, spectest harness
      design, ruleguard-style lint gates. AGENT.md rows P15.5, P15.6,
      P16.1-P16.7, P17.4, P17.5, P17.6. Apache-2.0 and LGPL-3.0 are
      compatible per the Free Software Foundation; no verbatim
      Erigon code is incorporated.
      Upstream: https://github.com/erigontech/erigon

  * mcp-language-server — MIT
      LSP-to-MCP bridge pattern (clangd subprocess + MCP-exposed tools).
      AGENT.md row P22.3.
      Upstream: https://github.com/isaacphi/mcp-language-server

  * AGENTS.md community convention
      Portable AI-agent onboarding file at repo root. AGENT.md row P22.1.

  * Codified Context Infrastructure (arXiv 2602.20478)
      Three-tier hot/specialized/cold memory pattern for AI-native
      codebases. AGENT.md group P22.

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For the full concept-borrow breakdown (per-row cross-references and
the machine-readable attribution matrix), see docs/ATTRIBUTIONS.md in
this source tree.

For questions about specific files, contact the project maintainer.
