Bitcoin Address Lookup: A Question of Privacy

Bitcoin wallets face a fundamental tradeoff: how to discover your transactions without revealing your addresses. Full nodes (2009) provide perfect privacy by downloading everything but require ~700 GB storage. Electrum (2011) achieves instant sync by transmitting your addresses directly to servers, exposing your complete transaction history. Block filters (2017-2019) restore privacy through client-side filtering - you download compact filters, check them locally, and only request matching blocks, revealing just block-level interest. Utreexo (2019) compresses the UTXO set from 11 GB to 480 bytes using cryptographic accumulators while maintaining full-node privacy, but requires 20% more bandwidth. Each approach trades privacy, storage, bandwidth, and convenience differently.