You should also understand that certification authorities cannot in all circumstances check the validity of a digital certificate on which a digital signature is based.

也应该理解证书颁发机构不能在所有情况下都验证数字签名所基于的数字证书的有效性。

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The Certificate Authority(CA) as the trustee third party is introduced, and an efficient fair electronic cash system is established based on the elliptic curve blind digital signature.

利用椭圆曲线上盲签名方法，引入认证中心（CA）作为可信的第三方，构建了一个高效的公平电子现金支付方案。

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So a certificate is "unique" based on (1) the subject, (2) the public key and (3) the the issuer (who applies a signature over (1) and (2)).

因此，证书基于(1)主题，(2)公共密钥和(3)发行者(在(1)和(2)上应用签名)是“唯一的”。

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