You cannot send digitally signed messages because you do not have any digital IDs.

由于没有数字标识，无法发送带数字签名的邮件。

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Digital IDs (also called certificates) are a way of proving your identity in electronic transactions.

数字标识(又称为证书)是在电子事务中证明您身份的一种方式。

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Digital IDs or Certificates are documents that allow you to prove your identity in electronic transactions.

数字标识或证书是一种可让您在电子商务中证实身份的文档。

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As phones and PDAs become transaction terminals and repositories for valuable information - credit card numbers, personal IDs, digital money, e-keys, bank passwords, even company secrets - much more will be at stake.

CNN: Virus protection coming for wireless users