First, the slide explained, some wallets that use tools called Simple Payment Verification or Electrum—designed to avoid storing the entire blockchain—leak certain information with every transaction. Nodes that receive a transaction message from those wallets can see not only the user’s IP address but all of their blockchain addresses and even their wallet’s software version, a tidy bundle of identifying information. Chainalysis had code-named the tool they use to collect that wallet data Orlando.
