It's a unique data file that stores several values regarding your account, device and the fw version of the Vita and some more, which need to be analyzed and added here. This file is UTF-8 encoded.
|id.dat||File: variable, only depending of the username length||dead link of someone id.dat||an example of id.dat|
|MID||Value, saved as Plain Text: 0x24||MID=455CB356BF73B0A530DE63C6A3B41D0F|| Unknown.
This value can be found under the table tbl_conf inside app.db.
|DIG||Value, saved as Plain Text: 0x2C||DIG=9F672EE122819AF9245A825D8F306CCD671B5281||Unknown.|
|DID||Value, saved as Plain Text: 0x2C||DID=297C4C05A145A6E374FE4FE65535E03DC1643F2C||DeviceID aka PSID|
|SVR||Value, saved as Plain Text: 0xC||SVR=03520000||FW Version (in this case 3.52) of the PSVita where the id.dat belongs too|
|AID||Value, saved as Plain Text: 0x14||AID=58CD7F52A6E493F1||NP Account ID|
|OID||Value, saved as Plain Text: 0xA||OID=username||Online ID : PSN Username to which the PSVita is bound too|