Paper 2024/1411

Design issues of ``an anonymous authentication and key agreement protocol in smart living''

Abstract

The Li et al.'s scheme [Computer Communications, 186 (2022), 110-120)] uses XOR operation to realize the private transmission of sensitive information, under the assumption that if only one parameter in the expression $a=b\oplus c$ is known, an adversary cannot retrieve the other two. The assumption neglects that the operands $b$ and $c$ must be of the same bit-length, which leads to the exposure of a substring in the longer operand. The scheme wrongly treats timestamps as random strings to encrypt a confidential parameter. These misuses result in the loss of sensor node's anonymity, the loss of user anonymity and untraceability, insecurity against off-line password guessing attack, and insecurity against impersonation attack. The analysis techniques developed in this note is helpful for the future works on designing such schemes.