What has been done to provide security for remote wireless updating of in-aircraft software components? Is it true that in the latest generation of Boeing aircraft some software components / Electronic Flight Bag data can be pushed to the flight remotely via a Wireless link? 

If so, what sort of safeguards are in place to preserve the integrity of such an update? How does the aircraft authenticate that the data sent is indeed legitimate? 

I'm curious to know the details. e.g. Are these conventional Ethernet networks over which the update gets pushed at the airport end? Is the final wireless transmission done by a COTS WiFi router? Does the update travel via the internet from (say) Boeing till the airport?
Boeing claims in this document:


  The 787 uses wireless (802.11 b/g) technology while at the gate to
  transfer maintenance data and update the Electronic Flight Bag (EFB).
  This is referred to as “e- Enabling” and it will allow airlines flying
  the 787 to operate more efficiently.


So, yes, they use a regular WLAN connection for transmitting data while on the ground.

The document continues:


  Upon weight on wheels the 787 attempts to authenticate specific ground
  access points. Information regarding the key configuration
  requirements and how the 787 authentication occurs requires the
  signing of a PIA.


I interpret PIA as Proprietary Information Agreement, a form of secrecy agreement. Boeing uses security through obscurity to safeguard the integrity of the connection.

If you want to know more, Boeing advises to contact 787terminalwireless@boeing.com. However, I doubt they will talk to you or me unless we are airport representatives with a credible need to know.