Overview

CIA stands for CTR Importable Archive. These files contain a compiled application which can be installed on CTR NAND, TWL NAND (part of the NAND used by DSi applications) and on the SD card.

Format

The CIA format has a similar structure to the WAD format.

The file is represented in little-endian.

The data is aligned in 64 byte blocks (if a content ends at the middle of the block, the next content will begin from a new block).

CIA Header

This is a 32 bytes long header (8 x uint32).

START SIZE DESCRIPTION
0x00 0x04 Archive Header Size (=0x2020 bytes) (Starts with 0x80 @ offset 0x0020)
0x04 0x02 Type
0x06 0x02 Version
0x08 0x04 Certificate chain size
0x0C 0x04 Ticket size
0x10 0x04 TMD file size
0x14 0x04 Banner size (0 if no banner)
0x18 0x04 APP file size
0x1C 0x04 0x80000000

The order of the sections in the header also is the order of them in the CIA file:

  • certificate chain
  • Ticket
  • TMD file data
  • APP file data
  • banner

The APP data can be either encrypted or cleartext, retail Download Play CIAs' APP data is always encrypted.

The banner starts with a 0xF0 large data block, whose purpose is currently unknown. Then at offset 0x400 into the banner section is the actual banner, which contains information about the creator, the first title and the second title (you can see them in the system settings):

START SIZE DESCRIPTION
0x00 0x04 Magic: 'SMDH'
0x04 0x04 Reserved = 0

This small 'table' is immediately followed by a meta-data described like that:

  • first title (0x80 bytes)
  • second title (0x100 bytes)
  • publisher name (0x80 bytes)

All encoded in UTF-16. This order will repeat 11 times (each block for different language supported).

Icons

At offset 0x2400 into the banner (inside the Banner's meta-data) to the end, There are two icons (Small - 24x24 & Large - 48x48).

Both of the icons are encoded in RGB655 (havn't been checked for sure yet) meaning 16bpp.

There's a header of 0x40 bytes and then comes the raw data.

The data is encoded in tiles (starting from size 8x8).

If the buffer is like this:

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Then the image would look like this:

x=0 x=1 x=2 x=3 x=4
0 1 4 5 16
2 3 6 7 ...
8 9 12 13
10 11 14 15