docs: add doc for encryption password entry

changelog.md

@@ -8,6 +8,7 @@
 
 * [1630](https://github.com/zeta-chain/node/pull/1630) added password prompts for hotkey and tss keyshare in zetaclient
   Starting zetaclient now requires two passwords to be input; one for the hotkey and another for the tss key-share.
+* [1731](https://github.com/zeta-chain/node/pull/1731) added doc for hotkey and tss key-share password prompts.
 
 ### Fixes
 

docs/zetaclient/migration_v12.2->v12.3.md

@@ -0,0 +1,34 @@
+## Hot Key and TSS key-share Passwords
+
+### Zetaclient
+Previously there were two environment variables being used to store passwords encrypting the tss key file and local operator keyring file:
+
+* HOTKEY_PASSWORD
+* TSS_FRAGMENT_SEED
+
+With this new change, these variables will no longer be valid.
+Instead, a series of prompts will appear asking for passwords using STDIN during the startup process.
+
+* Hot Key password
+* TSS Key share password
+
+If your key files are already encrypted, you can use the same passwords you provided in the environment variables.
+
+**It's extremely important to take note of these passwords or commit them to memory.**
+
+### Hot Key
+
+#### File backend
+
+* The hot key will use the existing keyring that holds your operator key. The file will be encrypted with your existing password,
+make sure to use this same password when starting the client.
+
+#### Test backend
+
+* You will still be prompted for a password, but you need to leave it blank which indicates the test backend is being used. 
+
+### TSS Key-Share
+
+During key-gen, the password you enter will be used to encrypt the generated key-share file. The key data will be stored in
+memory once the process is running. If the client needs to be restarted, this key-share file needs to be present on your
+machine and will be decrypted using the password you've entered.