If it was that easy, it wouldn't be very secure.
One hint to avoid disaster if you call around for cheaper options (other than Dealers).
When programming new keys from none on hand, TWO keys MUST be programmed into the system.
Recently one member was trying to avoid the tow bill & dealer charges and called a locksmith that was actually Dealer recommended for programming additional keys. They might have been OK on how to add them, but didn't get the erase & start from scratch right so the new key didn't work. Neither did the old one when it was found, as it HAD been erased from the system.
Second locksmith - tried & failed due to problems from the first attempt we assume. Now the owner has paid for a couple new keys, has his old one, and nothing works.
Towed to Dealer - THEY fail at reprogramming, end up replacing the instrument cluster before it can be programmed to work. Healthy bill for all that as you can imagine.
Bottom line, if you shop around make sure they know how to do it & RUN if they say "sure I can make a single replacement & reprogram it for you".
If you chose to replace the ECU, keys & lock cyl., you'll still need the existing key for the other locks. You'd need one from the same year & type (pzev or not if you shop US & Canada) that has been updated since new. Factory update for an '05 occasional hard starting situation is now something you'd have to pay for at the dealer if it wasn't done to the replacement.