Permutation-Based Lightweight Authenticated Cipher with Beyond Conventional Security

Lightweight authenticated ciphers are specially designed as authenticated encryption (AE) schemes for resource-constrained devices. Permutation-based lightweight authenticated ciphers have gained more attention in recent years. However, almost all of permutation-based lightweight AE schemes only ensure conventional security, i.e., about c / 2 -bit security, where c is the capacity of the permutation. This may be vulnerable for an insufficiently large capacity. This paper focuses on the stronger security guarantee and the better efficiency optimization of permutation-based lightweight AE schemes. On the basis of APE series (APE, APE R I , APE O W , and APE C A ), we propose a new improved permutation-based lightweight online AE mode APE + which supports beyond conventional security and concurrent absorption. Then, we derive a simple security proof and prove that APE + enjoys at most about min r , c -bit security, where r is the rate of the permutation. Finally, we discuss the properties of APE + on the hardware implementation.