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Deck-Based Wide Block Cipher Modes

October 3, 2023


Bart Mennink - Radboud University


We present two tweakable wide block cipher modes from doubly-extendable cryptographic keyed (deck) functions and a keyed hash function: double-decker and docked-double-decker. Double-decker is a direct generalization of Farfalle-WBC of Bertoni et al. (ToSC 2017(4)), and is a four-round Feistel network on two arbitrarily large branches, where the middle two rounds call deck functions and the first and last rounds call the keyed hash function. Docked-double-decker is a variant of doubledecker where the bulk of the input to the deck functions is moved to the keyed hash functions. As a consequence, the size of the inputs of the deck functions are constant and can be conceptually seen as stream ciphers. Concretely, docked-double-decker can be instantiated using the same primitives as Adiantum, without using any block cipher, arguably having a slightly more efficient design and being more secure in certain settings.

Presented at

The Third NIST Workshop on Block Cipher Modes of Operation

Event Details


    National Cybersecurity Center of Excellence (NCCoE)
    9700 Great Seneca Highway
    Rockville, MD 20850

Related Topics

Security and Privacy: encryption

Created October 03, 2023, Updated October 05, 2023