Abstract: Abuse－freeness is a new secure requirement proposed in contract signing protocols,and appears ambiguous.Based on the interactive theorem prover Isabelle/HOL,the paper deduces the unequivalent relation between “TTP’s abort decision” and “aborted contract signing”,gives formal definition of “contract signing failed”,proposes a new formal description of abuse－freeness,and verifies abuse－freeness of BW multi－party contract signing protocol．

摘要： 非滥用性是合同签署协议提出的新的安全需求,人们对它的描述还模糊不明。利用交互式定理证明器Isabelle/HOL推导了“TTP的aborted仲裁”与“失败的合同签约”的不等价关系,提出了“合同签约失败”的形式定义,提出了一个新的非滥用性的形式化描述,验证了BW多方合同签署协议的非滥用性。