True Key

TrueKey and McAfee are optional offers when downloading Flash Player installer:

A few possibilities to result in this:

• Using ad-blockers: Ad-blocker block the option offers, preventing users from seeing them.
• Some sites also post the online installer with the option offer, unbeknownst to Adobe an not authorized by Adobe.  If a non-adobe.com site was used to download the installer it's possible the installer with the the offers was used.

The easiest, quickest way to update Flash Player (without third-party offers) is to opt into Background Updates.  The Background Update service checks for a new version of Flash Player every day. If an update is not found the service goes back to sleep until it's time to check again.  If an update is available, Flash Player downloads and installs the update silently in the background.  No user intervention required. Similar to Google Chrome and Firefox automatic updates.  To opt into Background Updates at installation time, select the 'Allow Adobe to install updates (recommended)' option.  To opt into Background Updates after Flash Player has been installed launch the Control Panel and navigate to Control Panel\All Control Panel Items > Flash Player > Update tab.  Select the 'Allow Adobe to install updates (recommended)' option.