We, the authors, Editors and Publisher of the journal Connection Science, have retracted the following article:

Tian Liu, Xuchong Liu, Xiong Li, Ruhul Amin, Wei Liang & Meng-Yen Hsieh (2021) Cloud enabled robust authenticated key agreement scheme for telecare medical information system, Connection Science, DOI: 10.1080/09540091.2021.1901072

Since publication, the authors identified some technical issues that they had overlooked. In general, biometrics are data that owns fuzzy properties but the authors in this paper have neglected this technical point and the biometric information was authenticated using a hash function. Since the output of a hash function is sensitive to the input it cannot be applied to verify the validity of fuzzy data such as biometrics. Since this scheme is based on a hash function for biometric verification, it must not be used in real applications. The authors alerted the issue to the Editor and Publisher and all have agreed to retract the article to ensure the integrity of the scholarly record.

We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions.

The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as ‘Retracted’.

我们，期刊Connection Science的作者、编辑和出版商，已撤回以下文章：

Tian Liu、Xuchong Liu、Xiong Li、Ruhul Amin、Wei Liang 和 Meng-Yen Hsieh (2021) Cloud 为远程医疗信息系统启用了强大的认证密钥协议方案，连接科学，DOI：10.1080/09540091.2021.1901072

自出版以来，作者发现了一些他们忽略的技术问题。一般来说，生物特征是具有模糊属性的数据，但本文作者忽略了这一技术点，生物特征信息是使用哈希函数进行验证的。由于散列函数的输出对输入很敏感，因此不能应用于验证模糊数据（例如生物特征）的有效性。由于该方案基于用于生物特征验证的哈希函数，因此不得在实际应用中使用。作者将此问题告知了编辑和出版商，所有人都同意撤回该文章以确保学术记录的完整性。

在我们的决策过程中，我们已经了解了关于出版道德和诚信的政策以及关于撤回的 COPE 指南。

被撤回的文章将保持在线状态以维护学术记录，但将在每页上以数字水印标记为“已撤回”。