What is the "Authentication Key", or "A-Key" & how to get it back?

[snovvman]

I did some research, and it appears that Verizon systems relies on the A-Key while Sprint does not. Verizon can regenerate and send the A-Key to the phone, but I have not read the same for Sprint devices. I read that the A-Key is used to identify the device to the network.

For my Sprint device...

After a few ROMs, flashing, and hard reset, I discovered that my once populated "A-Key" field is now blank (##AKEY#--you will need your MSL to see). I remember seeing a string of text data within this field.

Mind you, my Vision log-in information and other settings (MIP, etc.) are all there and I can get to the Internet, send/receive PM, SMS, and make calls fine.

I'm just curious as to what A-Key is, how it works on the Sprint (and potentially roaming on other networks), and how to get it back. I contacted Sprint Advanced Data support, and they don't know. They did a remote IOTA and still no joy.

I appreciate any help. Happy Thanksgiving.