EFF1

EFF1, short for Efficient File Format 1, is an open, general-purpose data storage and transfer format designed for simplicity and performance, especially in resource-constrained environments. It aims to provide small overhead, fast parsing, and forward- and backward-compatibility while remaining language-agnostic.

The format was developed by the International Standards Alliance (ISA) with the goal of replacing older binary formats in embedded and data-logging contexts. The first stable release, EFF1 1.0, appeared in 2016, with subsequent minor updates to improve interoperability and tooling. It is intended to be implemented in multiple programming languages, including C and Rust, and is distributed under an open, royalty-free specification.

Technical characteristics include a binary container with a concise header, followed by a sequence of chunks. Each chunk begins with a 1-byte type, a variable-length length field, and the payload. Supported chunk types cover metadata, data payload, compressed payload, and checksums. UTF-8 text is stored natively, and numeric data use little-endian encoding. Data integrity can be ensured via CRC-32 or CRC-32C, while optional security features include AES-GCM-256 encryption for secured channels or encrypted storage. Built-in adapters allow lossless compression through selectable backends such as LZ77 or modern codecs.

Adoption and variants are modest but growing in niche areas like automotive telemetry and environmental sensing. Official variants include EFF1-Lite (reduced feature set), EFF1-EXT (expanded metadata), and EFF1-SEC (encryption-enabled). The specification emphasizes interoperability, clear licensing, and a reference implementation in multiple languages to encourage broad, royalty-free use.