Nand/private/movable.sed
| Offset | Size | Description |
|---|---|---|
| 0x0 | 0x4 | Magic "SEED" |
| 0x4 | 0x4 | This u8 must be zero |
| 0x8 | 0x100 | RSA-2048 signature over the 0x10-byte data at 0x108 |
| 0x108 | 0x8 | ? |
| 0x110 | 0x10 | AES engine keyY for 3 keyslots |
This file is transferred to the destination 3DS during a System Transfer. The keyY high u64 loaded from movable.sed, is a counter which is incremented on the source 3DS during a System Transfer. This keyY is the console-unique portion of these 3 keyslots. All of the data under sdmc/Nintendo 3DS/<ID0>/<ID1> and nand/data/<ID0> use these console-unique keyslots.
Movable.sed always exists on retail, however if this file doesn't exist the system will fall-back to using a console-unique keyY already in memory, with the last 8-bytes being loaded from the 8-bytes following that u64. Therefore, movable.sed presumably doesn't exist on development units.
The keyY is hashed with SHA256, the first 0x10-bytes from the hash is used for ID0 in sdmc/Nintendo 3DS/<ID0>/<ID1> and nand/data/<ID0>.