From now on, Gmail users will be able to see whether their communications with other email account holders - whether Gmail or any other email service - is secured. If it's not, there will be a red broken lock icon in the upper right corner of the message:
"Gmail has always supported encryption in transit using TLS, and will automatically encrypt your incoming and outgoing emails if it can,"
noted John Rae-Grant, Gmail Product Manager. Google's vocal and
obvious preference for this option has also pushed other email providers (Yahoo, Microsoft, Comcast, etc.) to offer end-to-end mail encryption to their customers.