Cryptology ePrint Archive: Report 2019/940

Security analysis of two lightweight certi ficateless signature schemes

Nasrollah Pakniat

Abstract: Certificateless cryptography can be considered as an intermediate solution to overcome the issues in traditional public key infrastructure (PKI) and identity-based public key cryptography (ID-PKC). There exist a vast number of certificateless signature (CLS) schemes in the literature; however, most of them are not efficient enough to be utilized in limited resources environments such as Internet of things (IoT) or Healthcare Wireless Sensor Networks (HWSN). Recently, two lightweight CLS schemes have been proposed by Karati et al. and Kumar et al. to be employed in IoT and HWSNs, respectively. While both schemes are claimed to be existentially unforgeable, in this paper, we show that both these signatures can easily be forged. More specifically, it is shown that 1) in Karati et al.'s scheme, a type 1 adversary, considered in certificateless cryptography, can generate a valid partial private key corresponding to any user of its choice and as a consequence, it can forge any users' signature on any message of its choice, and 2) in Kumar et al.'s scheme, both types of adversaries which are considered in certificateless cryptography are able to forge any signer's signature on an arbitrary message.

Category / Keywords: public-key cryptography / Certificateless cryptography, Cryptanalysis, Signature, Industrial Internet of Things, Healthcare Wireless Sensor Networks.

Original Publication (with minor differences): Journal of Computing and Security

Date: received 18 Aug 2019

Contact author: pakniat at irandoc ac ir

Available format(s): PDF | BibTeX Citation

Note: Please cite this article as: Pakniat, N. (2019). Security Analysis of Two Lightweight Certificateless Signature Schemes. Journal of Computing and Security, 5(2), 1-7. doi: 10.22108/jcs.2019.110889.

Version: 20190818:160336 (All versions of this report)

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