The document discusses Coinpunk, an open-source Bitcoin web wallet that aims to improve security over previous wallets by encrypting private keys in the browser rather than on a central server. It outlines the history of Coinpunk, from an initial version that stored private keys on the server to a new "New Wave" version that generates and encrypts private keys in the browser. The document also covers challenges in implementing strong cryptography in JavaScript and the potential for browser-side encryption to become more commonplace and secure.