Light-weight primitive, feather-weight security

Abstract

In [12], the authors present a new light-weight cryptographic primitive which supports an associated RFID-based authentication protocol. The primitive has some structural similarities to AES, but is presented as a keyed one-way function using a 128-bit key. Although a security analysis is included, this is at a high-level only. To provide a more concrete idea as to the security of this primitive, we therefore make three contributions: first, a structural attack requiring Op2 5 q plaintext/ciphertext pairs (and hence effort online) plus Op2 21 q effort offline, second algebraic attacks on round reduced versions of the primitive which requires only a single plaintext/ciphertext pair, and, third debunk the claimed attack of [36] on the same primitive. Our structural attack completely breaks the primitive and the algebraic attack highlights a crucial weakness of the primitive; we conclude that although one can consider countermeasures against these specific attacks, the design in general is questionable and should therefore be avoided.