Reconnecting Broken Money Trails: The Story of Demixing Technology
Every transaction on a blockchain is recorded and visible to anyone. So why is it still so hard to follow the crypto assets used in dark web drug deals all the way to the end? Because some technologies are designed specifically to break the trail.
ABC is taking part in a national R&D project, led by the Ministry of Science and ICT and the Korean National Police Agency, to develop an integrated system for drug investigations. Our role is to research technology that reconnects these broken money trails. Here is what the problem looks like and how we are approaching it.
Where the Trail Breaks: Mixing and Tumbling
Mixing and tumbling pool funds from many users or split them into small amounts and scatter them across addresses. The transaction records remain, but the link that says "this money went to that wallet" becomes blurred. Well-known examples include CoinJoin on Bitcoin, Tornado Cash on Ethereum, and mixing transactions on TRON.
In crimes where crypto assets serve as the means of payment, such as dark web drug trafficking, this is exactly where investigations hit a wall.
Reconnecting the Flow: Demixing
Demixing is a technique for identifying downstream transactions that are highly likely to be linked to the original funds after a mixing break. Rather than relying on a single clue, it looks at multiple signals together.
- Transaction timing and amounts
- Fund flow shapes and transaction patterns
- Relationships between wallets
Because each blockchain mixes funds differently, the analysis is tailored to the characteristics of CoinJoin, Tornado Cash, and TRON-based mixing.
What ABC Is Building
The official title of the project is "Development of an Integrated Drug Investigation System Linking Dark Web and Virtual Asset Transaction Tracking." It is led by the Department of Forensic Science at Sungkyunkwan University and runs for three years, from 2026 to 2028. The goal is to connect dark web user analysis, crypto asset transaction tracking, and drug advertisement detection into a single system.
ABC is responsible for two components.
- Demix Engine: a demixing engine that analyzes the likelihood of links between transactions
- Demix Data Platform: a platform that collects and manages transaction data from multiple blockchains
Going beyond collecting and managing transaction data and delivering analysis results, we plan to build a framework for verifying those results by also providing the evidence behind each candidate transaction. To be meaningfully used in real investigations, the system has to be able to explain “why this transaction.”
Building on BICScan
This research builds on the experience ABC has gained through BICScan, our blockchain intelligence service, in on-chain analysis, anti-money laundering (AML), and anomalous transaction detection. What this project adds is extending the scope of analysis to the post-mixing stage that has been difficult to trace until now.
As a technology that can support not only digital drug crime investigations but also crypto money laundering analysis, we will continue this research to help build a safer environment for digital asset transactions.