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Camellia

Algorithm​

Camellia (ISO/IEC 18033-3, RFC 3713, and related national profiles) is a 128-bit block cipher with 128-, 192-, or 256-bit keys. In NoxTLS, CamelliaCipher::new expands the key once into internal round-key tables; encrypt_block and decrypt_block run one 16-byte block at a time and return Result so callers can treat failures uniformly.

Round and FL-layer counts follow the Camellia definition for each key size (the CamelliaCipher implementation branches on 128-bit versus 192/256-bit material). Modes (CBC, CTR, CFB, OFB) layer IVs or counters on top of these primitives; see the per-mode pages below.

Purpose​

This page is the hub for Camellia in noxtls-crypto: build a CamelliaCipher, then pass &CamelliaCipher into the camellia_* mode helpers. Use Camellia when a Japanese or international standard or cipher suite names it; where the protocol allows a modern default, AEAD (for example AES-GCM or ChaCha20-Poly1305) is often simpler for integrity.

Mode pages

Rust API​

  • Crate: noxtls-crypto
  • Module path (conceptual): noxtls_crypto::sym (re-exported at crate root)
  • Primary symbols:
    • CamelliaCipher
    • CamelliaCipher::encrypt_block / CamelliaCipher::decrypt_block
    • Mode entry points (see mode pages above)

Functions and types:

  • CamelliaCipher::new(key) -> Result<CamelliaCipher> - Parameters: key is 16, 24, or 32 bytes. Behavior: runs the Camellia key schedule. Returns: CamelliaCipher on success, or InvalidLength if the key size is not supported.
  • Block primitives - encrypt_block(&self, block: &mut [u8; 16]) -> Result<()> and decrypt_block mutate one block in place; used by mode helpers and available for custom constructions.
  • Mode helpers - Take &CamelliaCipher plus a 16-byte IV or initial counter (per mode); CBC requires block-aligned buffers with no automatic padding. See each linked mode page for signatures and Result / Vec return types.

Feature flags and policy​

CBC, CTR, CFB, and OFB are in the default noxtls-crypto build. Camellia-ECB is exported only with hazardous-legacy-crypto.

Examples​

use noxtls_crypto::{CamelliaCipher, noxtls_camellia_ctr_apply};

let key = [0x12u8; 16];
let cipher = CamelliaCipher::new(&key)?;
let nonce_counter = [0u8; 16];
let plaintext = b"camellia-data";
let ciphertext = noxtls_camellia_ctr_apply(&cipher, &nonce_counter, plaintext);
let recovered = noxtls_camellia_ctr_apply(&cipher, &nonce_counter, &ciphertext);
assert_eq!(recovered, plaintext);
# Ok::<(), noxtls_core::Error>(())

Security and compatibility​

Treat IVs, nonces, and counters like other block-cipher modes: avoid reuse under the same key unless the standard defines a safe construction. Non-AEAD modes do not authenticate ciphertext; combine with a MAC or use AEAD where the protocol permits.