Beyond Anonymity - The Comprehensive Guide to Bitcoin Mixers

In an era of social media, online harassment and increasing terrorism threats, the role that anonymity plays in enabling these behaviours has been a growing cause for concern. People using anonymous or fake accounts are able to spread conspiracy theories, discriminatory commentary and other offensive material and can incite violence and terrorism - all from the safety of their computer screen. In some cases, they are even able to target victims repeatedly by moving between different anonymous accounts. This can be particularly distressing for victims who are afraid that their abuser will continue to follow them and attack them again from another screen or over the phone.

The ability to communicate online without revealing one’s identity allows bitcoin mixer whistleblowers to report bad news that companies and governments would rather not see; human rights workers to challenge repressive regimes; parents to create safe spaces for their children; and individuals with same-sex attraction, intersex identities or gender diversity to discuss their sexuality openly without fear of being 'outed' to their family and friends or harassed by their community. But it also enables repression and hatred by giving perpetrators a sense of impunity and the freedom to act in harmful ways.

There are many ways to protect one’s anonymity on the internet including software, browser extensions and encryption. The most technical approaches involve hiding the link between a user’s device and their location or identification information, such as IP address. There are also simpler methods, such as taking on a fictional identity or avatar, or using pseudonyms or aliases.

Cryptocurrency mixers (or tumblers) are a way to break the link between an incoming bitcoin transaction and the wallet used to spend it. Often, these services are run by volunteers and are free of charge - but they can suffer from a variety of leaks, such as timing correlation and address matching. These leaks can be overcome by a simple but effective strategy: requiring an adversary to search the blockchain for matching addresses over a wide time period.