The Information Commissioner’s Office has highlighted a rise in the number of reported incidents caused by a common problem with redacting documents that are later converted from a Microsoft Word file into a pdf. When using the black highlight text tool to remove personal information from a Word document, the redacted material appears hidden, before conversion to pdf. However, text redacted in this way is easily read merely by copying it from the pdf document and pasting it into Word.
ICO suggests the National Archive’s Redaction Toolkit is a useful resource, pdf 187KB.
(From ICO November Newsletter)