PrivateBond

PrivateBond is a friend's project. It was my first large freelance project: partly paid work, and partly a lot of unpaid time spent helping a friend. I was not a co-founder or a user of the product. I was the technical person behind its blockchain side, from April to July 2025, with June as the most intensive month.

Creators who share private photos and videos have no way to know who leaked them. PrivateBond gives every viewer a unique, invisibly marked copy, so a leaked file points back to the recipient it came from.

All of the smart contracts for the version of PrivateBond built on blockchain: an upgradeable core contract, a marketplace with escrowed bids, and integrations that let deposited funds earn yield. Plus the scripts, tests and web integration around them.

Smart contracts are unforgiving: once deployed they hold real money and cannot simply be patched. That meant upgradeable contracts behind a proxy, extensive testing on a test network before anything went live, and treating every external call as a security risk. It was the hardest engineering I had done at that point.

I do not count PrivateBond among my own projects, but it was a real technical challenge and my first experience of doing paid work for someone else's product. I stopped working on it in July 2025. The project continues without me, and today's site presents it as forensic watermarking for media sharing.