The Final Fantasy VII spin-off mobile game, Dirge of Cerberus: Lost Episode, was originally released in 2006 and featured fully voiced cutscenes. However, the game has been completely inaccessible since Square Enix shut down the verification servers for downloads and chapter transitions in 2018. Recently, Yuvi, a hacker and game preservationist, announced that he had successfully cracked the game's encrypted files and preserved them.
Yuvi stated that he joined the Final Fantasy VII: Before Crisis restoration team in 2024 and obtained the complete original files for Dirge of Cerberus: Lost Episode. However, possessing these original files was not enough to restore and preserve the game, as all files on the SD card were encrypted, and he never managed to obtain the decryption key. He and his team spent two years trying to acquire the key but ultimately failed. Nevertheless, he remained "determined to solve this problem. We have the data; we just need to decrypt it. Let's figure out a way together!"
He therefore adopted the most direct approach: brute-force cracking. After writing custom OpenCL software to decrypt PKZIP file headers, he spent $900 to build a massive GPU cluster. "I launched over 90 GPU servers to process this data quickly, including models like the RTX 4090, A4000, A4500, A5000, RTX 6000, and H200. At the time, more than 125 clients were running simultaneously. All combined, my processing speed approached 5,500 GKeys/s. This was more than 70 times faster than my single 7900 XTX."
With massive computing power, the cracking process that was originally expected to take several months was completed within just a few days. As a result, he successfully obtained a playable version of the game, which had been lost since 2018. He has also posted videos of the game on his YouTube channel. Notably, Square Enix had previously attempted to revive some elements from these lost games, and parts of the storyline from Dirge of Cerberus: Lost Episode have already been incorporated into the Final Fantasy VII Remake trilogy.
Foreign media outlets noted that Japanese mobile games from the early 2000s are arguably the most fragile part of video game history in terms of preservation. At that time, Japanese game developers lacked unified storage standards, meaning that once servers were shut down, games became completely inaccessible "digital waste." In addition to Dirge of Cerberus: Lost Episode, many other Final Fantasy series mobile games have also been lost, such as Final Fantasy VII: Before Crisis. However, thanks to current technological advancements, there is now a tangible possibility for players and developers to preserve classic older games.