feat: update readme

README.md

@@ -1,16 +1,14 @@
 # tiny-encrypt-rs
 
+**IMPORTANT**: To use tiny-encrypt, a Yubikey(https://www.yubico.com/products/) or CanoKey(https://www.canokeys.org/) is required.
+
 Tiny encrypt for Rust
 
-> Tiny encrypt rs is a Rust implementation of Tiny encrypt java https://git.hatter.ink/hatter/tiny-encrypt-java
+> Tiny encrypt rs is a Rust implementation of Tiny encrypt java https://git.hatter.ink/hatter/tiny-encrypt-java <br>
 > Tiny encrypt spec see: https://github.com/OpenWebStandard/tiny-encrypt-format-spec
 
 Repository address: https://git.hatter.ink/hatter/tiny-encrypt-rs mirror https://github.com/jht5945/tiny-encrypt-rs
 
-TODOs:
-
-* Encrypt subcommand
-
 <br>
 
 Encrypt config `~/.tinyencrypt/config-rs.json`:
@@ -44,6 +42,7 @@ Encrypt config `~/.tinyencrypt/config-rs.json`:
 ```
 
 Smart Card(Yubikey) protected ECDH Encryption description:
+
 ```text
 ┌───────────────────┐                     ┌───────────────────────────┐
 │Tiny Encrypt       │                     │Smart Card (Yubikey)       │