TL;DR
The 2025 IOCCC has announced its winners, featuring creative and highly obfuscated C programs. The contest saw a high volume of quality submissions after a four-year hiatus, with notable entries from around the world. The winners and their projects demonstrate ongoing innovation in code obfuscation.
The winners of the 2025 International Obfuscated C Code Contest (IOCCC) have been officially announced on the ‘Our Favorite Universe’ YouTube channel, showcasing a diverse array of highly complex and creative C programs. This marks the second consecutive contest after a four-year break, with a record-high number of submissions and high-quality entries, reflecting renewed interest and ongoing innovation in code obfuscation.
The IOCCC29, held in 2025, saw a competitive field with submissions from around the globe, including new participants such as Jingp49 from Taiwan. The contest’s judging panel selected winners across multiple categories, highlighting remarkable entries such as a Subleq computer emulator, a black hole punchcard Fortran interpreter, a patch/diff quine, and a GameBoy emulator, among others. The winners were announced after a detailed review process, with the main presentation available on YouTube, segmented for accessibility.
Among the notable winners are Yusuke Endoh, who secured three awards, Nick Craig-Wood with three wins, and Don Yang, also with three. The contest’s rules and guidelines underwent significant updates for 2025, aiming to improve transparency and organization. The entries reflect a wide range of programming ingenuity, from encoding schemes to minimalistic interpreters and complex obfuscated algorithms.
Why It Matters
This year’s IOCCC demonstrates the ongoing vitality of the programming community dedicated to obfuscation and code challenge culture. The high quality and diversity of entries underscore the importance of such contests for pushing the boundaries of coding creativity, which can influence areas like security, compression, and compiler design. Additionally, the global participation, including new authors, indicates expanding interest in niche programming arts.
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Background
The IOCCC, established in 1994, is a long-standing annual competition emphasizing highly obfuscated C code. After a four-year hiatus from 2020 to 2024, the contest resumed in 2025, attracting renewed attention and a record number of submissions. Previous contests have seen notable winners and innovations, with the 2025 edition continuing this tradition. The contest’s rules were updated in 2025 to enhance clarity and organization, reflecting ongoing community efforts to refine the challenge.
“The 2025 submissions set a new standard for creativity and complexity in obfuscated C code, with many entries pushing the limits of what can be achieved.”
— IOCCC Judge
“Winning three awards this year was a surprise, and I hope it inspires others to explore the boundaries of obfuscation.”
— Yusuke Endoh
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What Remains Unclear
While the winners have been announced, detailed technical analyses of each entry are still being prepared, and some submissions’ full workings remain complex and not fully explained publicly. The impact of these programs beyond the contest, such as potential applications or influence on other fields, remains to be seen.
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What’s Next
The IOCCC organizers plan to open submissions for the 30th contest towards the end of 2026, with a similar timeline as previous years. Post-contest, the judging panel will review feedback, and the community may submit improvements or alternative solutions to the winning entries via GitHub. Additionally, detailed write-ups and analyses of the 2025 winners are expected to be published in the coming months.
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Key Questions
Who were the top winners of the 2025 IOCCC?
The top winners included Yusuke Endoh, Nick Craig-Wood, and Don Yang, each securing multiple awards for their innovative obfuscated programs.
What kinds of programs won in 2025?
Notable entries included a Subleq computer emulator, a black hole punchcard Fortran interpreter, a patch/diff quine, and a GameBoy emulator, among others, showcasing diverse and complex obfuscation techniques.
How can I view the winning entries?
The winners are available on the IOCCC website, with source code and detailed remarks linked from their respective index.html pages. The main presentation is also segmented and hosted on YouTube.
When will the next IOCCC contest be held?
The next contest, IOCCC30, is planned to open in late 2026, with submissions closing in early 2027.
Are there opportunities to contribute or improve the entries?
Yes, the community is encouraged to submit pull requests via GitHub for improvements or alternative solutions, which the judges will consider if deemed better.
Source: Hacker News
