Forward security of the scheme means that even if the secret key of current time period is compromised, some security remains. It is impossible to forge the signature relating to the past.

方案的前向安全性保证了签名密钥可定期更新，即使当前时间段的签名密钥被泄漏，敌手也不能伪造先前的签名。

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Only five percent of the owners characterized the current period as a good time to expand.

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Only 4 percent think the current period is a good time to expand substantially, compared to an average of 18 percent between 2003 and 2007 and 17 percent for the period 1973 to 2007.

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He says the current period is the most exciting time he can remember in 36 years working in higher education.

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