MCT alleges the anti-hacking encryption written into the electronic control module will block any attempt to "read, write, and/or replace the standard ECU of the C8." If the ECU detects such an effort, and that "programming event fails," the Corvette will enter a "recovery mode" that requires a reboot. The coupe can be reprogrammed, but only by an entity with the proper encryption keys - meaning a trip on a flatbed to the dealer.
Unsurprisingly, folks aren't sure what to make of this report. Car and Driver thinks the encryption MCT speaks of is more about the anti-vehicle-hacking measures in the Digital Vehicle Platform, meant to keep bad actors from taking over a car. That would especially be true of an autonomous car, since the new architecture has been designed with the next decade of mobility advances in mind.
The idea of locked-down ECUs isn't new. European carmakers have inserted code to keep aftermarket fiddlers out of their engine bays for years now. The Nissan GT-R was billed as having an unhackable ECU when it launched. Even the current C7 Corvette employs measures to inhibit tuning. We see how things have turned out for all of those examples.
On the other hand, if we look at GM's ECM encryption from 2017 on its Duramax pickups and the next-order encryption on the 2019 Corvette ZR1, there could be something more substantive to the MCT report. GM began installing new VIN-specific ECU software on its L5P Duramax trucks in 2017, and in 2018 forums were still calling it uncrackable. Depending on your definition of "cracked," versus "rebuilt," HP tuners out of Buffalo Grove, IL unlocked the L5P, but it didn't happen until August of last year and there are a ton of asterisks involved according to a story in Diesel World magazine. There's also hefty cost - $1,800 to $2,500 to exchange a stock L5P Duramax ECM for a tuned version, and another $300 for the MPVI2 tool to flash the ECM.
The Corvette ZR1 encryption went even further than on the Duramax trucks, featuring VIN-specific rolling codes and constantly evolving digital signatures that can be changed or restored via OnStar when alterations are detected. John Hennessey said he tried to crack the E99 ECU for 11 months but couldn't do it, and was about to give up on the ZR1. HP Tuners again cracked the code apparently, but it didn't happen until April 2019, and the ECU exchange is again spendy, from $2,000 to $2,500. Hennessey's HPE1200 tune for the ZR1 came out that same month.
Nothing will stop tuners from trying, of course. But it's possible the C8 Corvette will make tuning much harder than before.