Paper 2025/1235 Original: eprint.iacr.org/2025/1235 ↗

HiAE Remains Secure in Its Intended Model: A Clarification of Claimed Attacks

Abstract

HiAE is a recently proposed high-throughput authenticated encryption algorithm that achieves exceptional performance on both x86 and ARM architectures. Following its publication, several cryptanalysis papers have claimed that HiAE’s 256-bit encryption security is broken under the nonce-respecting model. In this note, we clarify that the claimed attacks rely critically on submitting forged-tag decryption queries — a type of behavior explicitly excluded by HiAE’s original security model. HiAE was designed under a standard nonce-based AEAD setting without decryption oracle access, offering 256-bit security against key and state recovery, and 128-bit security against forgery. This design approach follows the same principle as well-known schemes such as AEGIS and MORUS. The conclusion that HiAE is broken is based on a misinterpretation of its security model, as the attacks rely on conditions that the design explicitly excludes.