[10] Historically, encrypted data is quite rare, but even the very simple means available throughout history have provided many examples of documents that can only be read with great effort.

For example, it took the capacity of a distributed computing project to break the mechanically generated code of a single brief World War II submarine tactical message.

[11] As more records are stored in digital form, there have been several measures to standardize electronic file formats so software to read them is widely available and can be re-implemented on new platforms if necessary.

In 2007, the chief information officer of the UK's National Archives stated "We welcome open-source software because it makes our lives easier".

[15] In July 2007, Microsoft created a partnership with the UK's National Archives to prevent the digital dark age and "unlock millions of unreadable stored computer files".

[16][17][18] UK's National Archives now accepts various file formats for long-term preservation, including Office Open XML, PDF and OpenDocument.

Some of these, such as David Anderson and Jon Tilbury, view it as alarmist rhetoric, maintaining that the notion of a "dark age" incorrectly states the current condition.

These include Marilyn Deegan and Simon Tanner's claim that the Gutenberg printing revolution led Europe out of the Dark Ages, a period said to be marked by the loss of knowledge of the learning of the ancient Greeks and Romans.

[21] It is argued that knowledge and information about classical learning had been recovered during the Middle Ages and it was not mainly due to the printing revolution but, instead, was largely a result of the intellectual exchange between Islamic and Christian cultures.