Blocktag: Design And Applications Of A Tagging System For Blockchain Analysis

Annotating blockchains with auxiliary data is useful for many applications. For example, criminal investigation of darknet marketplaces, such as Silk Road and Agora, typically involves linking Bitcoin addresses, from which money is sent or received, to user accounts and web activities. We present BlockTag, an open-source tagging system for blockchains that facilitates such tasks. We describe BlockTag's design and demonstrate its capabilities through a real-world deployment of three applications in the context of privacy research and law enforcement.