(Sony calls it "Send Key")

00: BYTE  Command byte A3
01: BYTE  unused (might contain LUN)
02: DWORD Object Number
06: BYTE  unused
07: BYTE  Magic Byte BD
08: WORD  Size of cryptographic data
0A: BYTE  key type
0B: BYTE  unused

(Sony calls it "Request Key")

00: BYTE  Command byte A4
01: BYTE  unused, send as Zero (might contain LUN)
02: DWORD Object Number
06: BYTE  unsused
07: BYTE  Magic Byte BD
08: WORD  Size of cryptographic data
0A: BYTE  key type
0B: BYTE  unused

This data packet is sent from the Host to the HiMD device

00: WORD  Length, must be 0012
02: WORD  unsused
04: BYTES 8 bytes "Leaf ID of Host"
0C: BYTES 8 bytes "Nonce from Host"

This data packet is sent from the HiMD device to the Host, the expected length is 43C (i.e. header + 64 keys?)

00: DWORD unknown, maybe length in first WORD
04: BYTES 16 bytes "Disc ID"
14: BYTES 8 bytes "MAC from Device"
1C: BYTES 8 bytes "Leaf ID of Device"
24: BYTES 8 bytes "Nonce from Device"
2C: BYTES The "local EKB of the Device" Starts with its length in 16 byte units - 1

This data packet is sent from the Host to the HiMD device

00: WORD  Length, must be 41A
02: WORD  unused
04: BYTES 8 bytes "MAC from Host"
0C: BYTES The "local EKB of the Host"

This data packet is sent from the HiMD device to the Host (expected length 404) While this packet is never explained in the HiMD Transfer Tool for MAC, it looks suspiciously like the next one, just the other transfer direction.

00: DWORD unknown, length?
04: BYTE  unknown, but used
05: BYTE  bit flags. Bits 6,7: encryption type (0=plain, 2=des ecb, 3=des cbc)
                     Bit  5:   MAC flag
                     Bit  4:   DIR flag
06: WORD  length of following data
08: DWORD unknown, but used
0C: BYTES data, length from field 6.

This data packet is sent from the Host to the HiMD device

00: WORD  length (must be 404)
02: WORD  unused
04: BYTE  ICV slot number (must be between 0 and 31)
05: BYTE  bit flags, same bits used as in Type 33
06: WORD  length of ICV data
08: WORD  Revision
0A: WORD  unknown, but used
0C: BYTES ICV data
XX: BYTES 8 Bytes MAC