When designing Keychat, we considered the following disadvantages of the Signal App. 1、Signal App requires phone number registration. Users do not have their own self-sovereign ID. 2、Signal App users can only use Signal's servers, with no option to use third-party or self-hosted servers. 3、Signal App integrates a shitcoin called MobileCoin. 4、Signal App relies on donations and loans from billionaires, making it difficult to sustain. Keychat proposed corresponding improvements for these disadvantages. 1、Keychat only requires generating a Nostr key. Users have their own self-sovereign ID. 2、Keychat users can freely choose which relay to use or run their own relay. 3、Keychat aligns with Bitcoin. 4、Keychat's economic model with Bitcoin ecash stamps is more reliable and sustainable. 5、Keychat offers better metadata privacy because it allows continuous changing of receiving addresses, sending addresses, and relays.