Brian:
The Public Key is -in- the actual Certificate, which can be downloaded from Dev Account/Member Center.
When you manually generate a Certificate, you first need to generate a Certificate Signing Request (CSR) via Keychain Access. When this is done, both Public and Private keys are generated. The private key is automatically saved to your keychain on your Mac; the public key is included in the CSR file sent to the Provisioning Authority. One of the items contained in the generated certificate sent back from the Provisioning Authority will be the public key.
If you're not already familiar with Keychain Access on your mac, my advice is to open/run it and browse around so you can at least witness what items your keychain is holding onto for you. Everyone has a keychain on their mac, BTW, not just devs.
My advice is to backup your mac. Doing so will include your keychain items and your dev projects...a very good practice if you haven't done so by now.
As for a year from now, new ones are generated each time you go thru the process to renew your Developer Program account, old ones expire.
In the interim, backups are recommended should you lose access to your mac for whatever reason and you need to rebuild your IDE, but the reality is that with the proper hoop jumping, meaning going thru the same process you did originally, you can recreate them again, however, being able to recover from backups will reduce the impact of convincing your IDE that new ones are accepted throughout.
Ken
