Multiparty DSA Signature Generation without Simultaneous User Operations

Yoshiki SAMESHIMA  Hideaki SAISHO  Kazuko OYANAGI  Tsutomu MATSUMOTO  

IEICE TRANSACTIONS on Information and Systems   Vol.E87-D   No.8   pp.2095-2105
Publication Date: 2004/08/01
Online ISSN: 
Print ISSN: 0916-8532
Type of Manuscript: PAPER
Category: Application Information Security
threshold multisignature,  Digital Signature Algorithm,  multiparty protocol,  cryptography,  information security,  

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The authors present a multiparty signature generation (MSG) scheme of the Digital Signature Algorithm (FIPS 186-1). The scheme is based on a simple idea, however, it is much more convenient in usability in the real world than existing MSGs. The scheme has the following properties: (1) valid signatures are generated with odd n split private keys, (2) broadcast messages between the key holders are hidden from them, so that the n key holders do not need to process signature generation simultaneously, (3) even if up to t (= ) split keys are stolen, the adversary can get no information on the private key, (4) the scheme is as secure as the original signature algorithm against chosen message attack, and (5) the scheme is efficient in the sense that an implementation on smart card has demonstrated practical performance for interactive use with human user.