These icons appear in the received email sent from MeSince and in the interface of writing an email (email sent from other Email client may not display any of them). When clicking an icon, a popup sentence will give you its meaning. The first icon above means that the email is encrypted, and is not possible to be read by any third party; the second icon, indicates that the email has been digitally signed, which ensures that the email has not been tampered; the third icon, indicates that this email sent time is from the trusted time stamp server, which warrants the authenticity and accuracy of the email sending time; the fourth icon, indicates the email sender’s validation level is level 1(V1), which means only email is validated.
When you start to write email, the four icons are displayed in default. The first one means you want to send encrypted email, the second icon means you want to sign the email, the third icon means a timestamp signature will be added to the email, and the fourth icon is your current identity validation level. If it is V1, it means only the email is validated, and if it is V2/V3/V4, it means your identity is validated to related level -- Identity Verified and Trusted.
Please also refer to the MeSince UI Icon
Meaning for detailed instructions.