STFS

STFS (Secure Transacted File System) is the file system used by the Xbox 360 for all packages created and downloaded by the system. It is protected using a series of SHA1 hashes and a RSA signature. STFS is commonly found in Xbox 360 Content Packages (XContent), but is not limited to those only as the PEC (Profile Embedded Content) files employ STFS. The two known categories for STFS are read-only and writeable. Read-only content packages are found with a PIRS/LIVE signed header and writeable content packages are console signed (CON).

Directory Entries

The value at 0x37E (File Table Block Number on the structure above) determines where the file table begins. As it is a block number, you will have to convert it to an offset. I'm not gonna write that all down atm, later.

Each embedded file starts at a 4096 byte boundary. The optional space between embedded files is filled with null bytes.

The file listing consists of entries which have the format below. The listing ends with an entry consisting of only null bytes.

Offset	Length	Type	Information
0x0	0x28	ascii string	File name, null-padded
0x28	0x1	byte	Length of file name, plus flags
0x29	0x3	signed int24	Number of blocks allocated for file (little endian)
0x2C	0x3	signed int24	Copy of 0x29
0x2F	0x3	signed int24	Starting block number of file (little endian)
0x32	0x2	signed short	Path indicator (big endian)
0x34	0x4	unsigned int	Size of file in bytes (big endian)
0x38	0x4	signed int	Update date/time stamp of file
0x3C	0x4	signed int	Access date/time stamp of file

Byte 0x28 also has two flags: bit 6 and bit 7. The meaning of bit 6 is unknown, bit 7 indicates that the file is a directory.

The path indicator indicates the path of the file. -1 (0xFFFF) means that the file is in the root directory, any other value V refers to the (sub)directory which is listed as the Vth entry in the listing (counting from 0). Directories can nest.

The FAT format is used for the date/time stamps of the files.