This is really about how to make redacted PDFs. In some ways, this is similar to the new USN sub where they gave a video and online tour, including the high tech computer servers!
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Through a technical error by the Ministry of Defense, a well kept secret was published in an online document. The secretive information was blacked out in the document, but instead of actually removing it, the text was formatted to match the background, leaving all the text in place. By simply copying and pasting into another document, the blacked out text was revealed, which contained sensitive information about nuclear submarines. The documents on the website are released in PDF formats to the public.
The BBC reported that the mistakenly released documents contained information about both US and UK submarine reactors being vulnerable to attacks from enemy submarines, information that could potentially turn fatal if it landed in the wrong hands.
The embarrassing mistake was quickly taken down and fixed after media outlets reported the error. The Ministry of Defense says they are working to ensure that mistakes like this don't happen again.
http://www.bbc.co.uk/news/uk-13107413
