Cryptology ePrint Archive: Report 2021/528

Verified Multiple-Time Signature Scheme from One-Time Signatures and Timestamping

Denis Firsov and Henri Lakk and Ahto Truu

Abstract: Buldas, Laanoja, and Truu designed a family of server-assisted digital signature schemes (BLT signatures) built around cryptographic timestamping and forward-resistant tag systems. The original constructions had either expensive key generation phase or stateful client-side computations.

In this paper, we construct a stateless tag system with efficient key generation from one-time signature schemes. We prove that the proposed tag system is forward-resistant and when combined with cryptographic timestamping, it induces a secure (existentially unforgeable) multiple-time signature scheme. Our constructions are developed and verified using the EasyCrypt framework.

Category / Keywords: cryptographic protocols / digital signatures, EasyCrypt, formalized cryptography, timestamping

Original Publication (with minor differences): IEEE CSF 2021

Date: received 21 Apr 2021

Contact author: denis firsov at guardtime com

Available format(s): PDF | BibTeX Citation

Version: 20210423:122611 (All versions of this report)

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