tc_block_cipher

A Rust workspace for block ciphers. It holds tc_block_cipher, the shared traits, errors and key containers through which an engine is initialized and processes one block, and the crates built on it: the engines tc_aes, tc_des, tc_aria, tc_rc_cipher and tc_dstu7624; tc_block_modes, the modes of operation that run over any of them; and tc_block_padding, the padding schemes for the modes that process whole blocks. Each crate is published separately and keeps its own README, changelog, and validation commands.

Crates

Crate	Version	Description
tc_block_cipher		Initialization and single-block processing traits, reusable error types, and key containers that borrow, or own and wipe, key bytes. No algorithm, mode, padding or authentication. no_std, no unsafe, depends only on tc_zeroize; a default-off alloc feature adds a vector-backed key container.
tc_aes		AES-128, AES-192 and AES-256 with AES-NI, table-based and small-footprint engines, and a dispatcher that picks the safest one at runtime. no_std, no allocator; depends on tc_block_cipher, tc_zeroize, and tc_runtime on x86 only. A default-off rustcrypto feature adds a constant-time engine backed by RustCrypto's aes.
tc_des		DES and EDE Triple DES for legacy interoperability, with table-based engines and dispatchers that pick an engine at compile time. Every engine is variable time. no_std, no allocator, no unsafe; depends on tc_block_cipher and tc_zeroize. A default-off rustcrypto feature adds engines backed by RustCrypto's des, which the dispatchers then use because they leak less.
tc_aria		ARIA-128, ARIA-192 and ARIA-256 (RFC 5794) with a table-based engine and a dispatcher that picks an engine at compile time. Every engine is variable time. no_std, no allocator, no unsafe; depends on tc_block_cipher and tc_zeroize. A default-off rustcrypto feature adds an engine backed by RustCrypto's aria, which the dispatcher then uses.
tc_block_modes		ECB, CBC, CFB, OFB and CTR modes of operation over any engine, and key-and-IV containers that borrow, or own and wipe, their bytes. Each mode adds only data-independent work, so it is constant time exactly when its engine is. no_std, no allocator, no unsafe; depends on tc_block_cipher and tc_zeroize. A default-off alloc feature adds runtime-sized modes and a vector-backed container.
tc_block_padding		PKCS#7, ISO 7816-4, ANSI X9.23, TBC and zero-byte padding for the modes that process whole blocks, added and checked in constant time with respect to the block contents. no_std, no allocator, no unsafe, no dependencies. A default-off rand_core feature adds ISO 10126 padding, drawing its filler from a generator the caller supplies.
tc_rc_cipher		RC2, RC5 and RC6 for legacy interoperability, with a portable RC2 engine and a dispatcher that picks an engine at compile time. RC2 is variable time; RC5 and RC6 are constant time on processors with fixed-latency rotations and, for RC6, multiplication. no_std, no allocator, no unsafe; depends on tc_block_cipher and tc_zeroize. A default-off rustcrypto feature adds an RC2 engine backed by RustCrypto's rc2, and a default-off alloc feature adds parameter types that own and wipe the key.
tc_dstu7624		DSTU 7624:2014 (Kalyna) with 128-, 256- and 512-bit blocks and one- or two-block keys. Every engine is variable time. no_std, no allocator, no unsafe; depends on tc_block_cipher and tc_zeroize.

tc_block_cipher defines the contract and knows no algorithm; each engine crate implements it and documents its own key lengths and timing guarantees. tc_block_modes builds on the contract alone, so its modes work with any engine.

Requirements

Rust 1.85 or later, edition 2024. Every crate builds without std and reaches the heap only through the default-off alloc features of tc_block_cipher, tc_block_modes and tc_rc_cipher.

Rust 1.85 is the earliest compiler for edition 2024, and it is guaranteed for every build that uses only this workspace's crates and their tc_* dependencies. A feature that enables a third-party crate, such as the rustcrypto features of tc_aes, tc_des, tc_aria and tc_rc_cipher or the rand_core feature of tc_block_padding, follows that crate's minimum Rust version instead, and dev-dependencies used only by tests and benchmarks are exempt. The workspace lock tracks the latest dependency releases, so CI on stable tests what a user on a current toolchain resolves.

Workspace checks

cargo test --locked
cargo test --locked --all-features
cargo fmt --all -- --check
cargo clippy --locked --all-targets --all-features -- -D warnings
cargo doc --locked --no-deps --all-features

CI additionally runs these on Linux x64, i686 and ARM64, macOS ARM64, and Windows x64, tests the AES dispatcher with AES-NI detection disabled, checks the wasm32-unknown-unknown and aarch64-unknown-none targets and each crate's dependency set, checks the build that Rust 1.85.0 covers, and verifies the package archives. See .github/workflows/ci.yml.

License

Licensed under either the MIT license or the Apache License, Version 2.0, at your option.