A small padlock icon for the encryption would be perfect in Notes client.

For inotes & VOP there is a identical icons for signed & encrypted emails (NRPC & SMIME).

As per the inotes product document there is a statement, "If a message is encrypted, a padlock icon displays next to the sender's name. If a message is signed, a seal icon appears. If trust cannot be verified or if the message has been tampered with, a broken seal icon appears. "

Reference Document : https://help.hcltechsw.com/inotes/11.0.0/sec_encrypt_sign_messages_t.html

Using Notes client there is no identical icons to differentiate normal email & encrypted or sign or SMIME email.

In the notes client for NRPC encrypted emails client shows a information below sender as "This message is encrypted and digitally signed." But we need a padlock icon displays next to the sender's name using notes client same as iNotes & VOP.