Hi @jerinhannah,
Please refer the following post which will disable the text box of the chat window when there is an entity node displaying templates.
https://test-discourse.kore.ai/t/disable-chat-text-box-field-for-list-entities/1402
Here, based on a condition, we have made the chat window text box read-only.
You can use the similar procedure and write the style classes in chatwindow.css to mask the characters in the chat window text box based on condition.
Let us know if you need any further clarification.
Regards,
Yoga Ramya