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Camellia-ECB

Algorithm​

Camellia is a 128-bit block cipher. Electronic codebook (ECB) encrypts each 16-byte block with the same key and no initialization vector: identical plaintext blocks always yield identical ciphertext blocks, so message structure can leak.

These helpers require block-aligned input (length multiple of 16). They do not add or remove padding; callers must pad or use another mode (for example Camellia-CBC).

Purpose​

Expose Camellia-ECB only for legacy interoperability, tests, or as a primitive inside a higher-level construction. Do not use ECB as the sole protection for long or formatted messages; prefer Camellia-CBC, Camellia-CTR, or an AEAD where the protocol allows.

Rust API​

  • Crate: noxtls-crypto
  • Module path (conceptual): noxtls_crypto::sym (re-exported at crate root only when the feature below is enabled)
  • Primary symbols:
    • CamelliaCipher
    • noxtls_camellia_ecb_encrypt
    • noxtls_camellia_ecb_decrypt

Functions and types:

  • CamelliaCipher::new(key) -> Result<CamelliaCipher> - Parameters: key is 16, 24, or 32 bytes (128-, 192-, or 256-bit Camellia). Behavior: expands the Camellia key schedule. Returns: CamelliaCipher on success, or InvalidLength for unsupported key sizes.
  • noxtls_camellia_ecb_encrypt(cipher, input) -> Result<Vec<u8>> - Parameters: cipher is an initialized CamelliaCipher; input must be block-aligned. Behavior: Camellia-ECB encryption block by block. Returns: ciphertext Vec<u8> of the same length, or InvalidLength if misaligned.
  • noxtls_camellia_ecb_decrypt(cipher, input) -> Result<Vec<u8>> - Parameters: same cipher; input is ECB ciphertext, block-aligned. Behavior: Camellia-ECB decryption. Returns: plaintext Vec<u8> of the same length, or InvalidLength if misaligned.

Feature flags and policy​

noxtls_camellia_ecb_encrypt and noxtls_camellia_ecb_decrypt are compiled and exported only when hazardous-legacy-crypto is enabled on noxtls-crypto.

Examples​

// Requires `noxtls-crypto` with feature `hazardous-legacy-crypto`.
use noxtls_crypto::{CamelliaCipher, noxtls_camellia_ecb_decrypt, noxtls_camellia_ecb_encrypt};

let cipher = CamelliaCipher::new(&[0x61u8; 16])?;
let plaintext = [0xEEu8; 16];
let ciphertext = noxtls_camellia_ecb_encrypt(&cipher, &plaintext)?;
let recovered = noxtls_camellia_ecb_decrypt(&cipher, &ciphertext)?;
assert_eq!(recovered, plaintext);
# Ok::<(), noxtls_core::Error>(())

Security and compatibility​

ECB does not hide repeated plaintext blocks and provides no integrity. Keep usage narrow and reviewed; record hazardous-legacy-crypto in your SBOM when enabled.