Whistleblowing platform WikiLeaks has released a fresh 88GB 'insurance file' to the web in anticipation of a mysterious upcoming announcement – but what could be lurking inside? While the content of the elusive torrent file remains unknown, speculation is rising it may be linked to the promised data on presidential candidate Hillary Clinton.

The file, which serves as a 'deadman's switch', is locked with 256-AES encryption and can only be opened by a second decryption key held by WikiLeaks. Previously, the organisation has uploaded similar files which reached a whopping 400GB in size – promising to release the data should anything happen to the website or its exiled editor-in-chief.

First posted to the web on 17 June, WikiLeaks posted a link to the file alongside the message: "Protect our coming publications". While the group did not elaborate further on what upcoming leaks would be, Assange has recently touted plans to released fresh troves of data from the personal email server of Clinton. He told ITV: "We have upcoming leaks in relation to Hillary Clinton. WikiLeaks has a very big year ahead."

These statements were made before a suspected Russian hacker dubbed 'Guccifer 2.0' sent files compromised from the Democratic National Committee (DNC) to the WikiLeaks website, which likely only added to the mass of compromised, and potentially sensitive, information.

After the hack at the DNC Guccifer, who is suspected to have close links to the Russian government, released a selection of files on a WordPress-hosted website, however also told The Smoking Gun via email the full cache had been sent to WikiLeaks. The full scope of the stolen documents remains unknown, however it seems unlikely that text-based files alone would amount to 88GB.

As noted on Heavy.com, a Reddit thread about the Insurance file speculated about what could be in the data dump – if anything worthy at all. "WikiLeaks said they have Hillary's emails to release soon. Today they posted this 'insurance file'. This usually implies they will have a release coming soon and this file is the backup in case the government or other people try to prevent it happening. It's thus fair to assume this file is the emails," wrote one user.

Whatever the case, until the second decryption key is released, no-one other than Assange knows what exactly is in the files. However, while so-called insurance files have been used in the past, they have not always remained private.

Protect our coming publications. Torrent WIKILEAKS INSURANCE 2016-06-03 (88 Gb encrypted) https://t.co/j4V8NH2Xmn pic.twitter.com/wwc9Pe0e0J — WikiLeaks (@wikileaks) June 17, 2016

Back in 2011, a collection of around 251,000 US State Department documents held in a secret file leaked onto the internet after the password was exposed amid disagreements between Assange and former WikiLeaks' staffer Daniel Domscheit-Berg. Upon analysis, it reportedly contained unredacted raw data from diplomatic cables.

In any case, one interview between Assange and Google's Eric Scmidt from 2011 shined some light on the controversial storage of such sensitive information. "We openly distribute encrypted backups of materials that we view are highly sensitive that we are to publish in the coming year," Assange said. "Ideally, we will never reveal the key [...] redactions sometimes need to be done on this material."

Assange just started his fifth year in the Ecuadorian embassy in London after gaining political asylum back and entering the premises back in June 2012. Most recently it was revealed that Swedish authorities have agreed to travel to the embassy to question the WikiLeaks founder about allegations of sexual misconduct – which he denies.