Thus, this information is absolutely confidential.

因此，这方面的资料是绝对保密。

youdao

However, we suggest you to provide your actual information and we promise it's absolutely confidential.

不过，在注册用户的时候，我们建议您务必输入您的真实信息，我们会为您绝对保密。

youdao

This must be kept absolutely secret.; This is strictly confidential.

这事绝对保密。

《新英汉大辞典》

This level of approval only comes following a process which is rigorous and absolutely necessary given the highly confidential nature of the communications being transmitted.

ENGADGET: BlackBerry 10 not secure enough for UK government workers -- yet (updated: GCHQ responds)

We understand wanting reviewers to sign non-disclosure agreements (not a big deal, though we generally refuse to sign them ourselves) or divulge confidential information, but trying to squash all rumors and speculation about unreleased gadgets on user bulletin boards is absolutely freaking stupid and ultimately counterproductive.

ENGADGET: HP's buzzkill