Bitcoin wallets have come a long way from being mere digital storage systems for cryptocurrency. A wallet in the early days of Bitcoin was virtually a software implementation that produced and held private keys, giving users control over their coins. Today, the Bitcoin wallet ecosystem is much more evolved with high-level cryptography, multi-layered security architectures, and privacy-centric functionalities. Knowing these esoteric wallet concepts is of utmost importance to any user wishing not only to store Bitcoin, but to store it, spend effectively, and even use it in the new decentralized apps.