Detecting Address Clusters of Input Addresses

Here, we deal with UTXO-based cryptocurrencies.

One Input – One Output – Sweep

Suppose a transaction has only one output. It is reasonable to assume that a user swept some of its UTXOs. This means the sending address and the receiving address probably belong to the same user (self-transfer).

Multiple Inputs – One Output – Consolidated Spend

Like in a sweep, the common interpretation is that all involved in this transaction belong to the same user. The purpose of such a transaction might be to consolidate several addresses to a single one.

If a transaction has two or more inputs, it is reasonable to assume that the same user controls all inputs. Two users rarely join to create one transaction. One case where this heuristic breaks is a coinjoin. Here, special wallets collect many users and combine their UTXOs to obscure the connection between inputs and outputs.