SpotPass

SpotPass is a Nintendo 3DS feature that allows the 3DS to automatically download content, notifications, and software when it's in standby mode.(SpotPass may download/upload some content while the 3DS is in "active" mode, but *only* if the currently active app uses SpotPass) SpotPass can upload content as well. Software downloaded with SpotPass is stored on SD card.

SpotPass Internet communications are mostly HTTPS transfers.

In System Settings, you can disable SpotPass automatic title downloading, but it states that important software will still downloaded.(This only disables downloading of free titles via SpotPass)

'nasc.nintendowifi.net' confirmed usages:(not SpotPass related)

• Friends List applet requires this server to be 'Online' (most likely the reason for regular requests to this server)
• Required for initialization of eShop, (for first time eShop users). Not required for using eShop after first use.

In some cases the BOSS module will add the following URL parameter to HTTPS requests, when connected to a Nintendo Zone AP: "ap=<NZoneApNum>" or when using a specific system model: "tm=<SystemModelNumber>". The Old 3DS and Old 3DS XL don't set this value.

policylist

Every time the system connects to the wifi AP, the BOSS ("Background online storage service" = SpotPass) module itself will download the cleartext xml policylist: "https://nppl.c.app.nintendowifi.net/p01/policylist/3/<countrycode>". This policylist contains a list of SpotPass tasks for certain titles. This policylist can control whether the specified tasks are processed at all.

As of the policylist updated 2017-11-08, this stops the OlvNotf (Miiverse notification sync) task for 000400300000bc00, 000400300000bd00, 000400300000be00 for all regions and basho0 for the Home Menu. Japan also has the 9ER_NTD task blocked for いつの間にテレビ (0004000000034700).

User Agent

The default user-agent used for SpotPass HTTPS requests (including the policylist) has the following format:

<user agent codename>-<user agent version>/<printed hex u64 LocalFriendCodeSeed>-<printed hex u64 Friend Code>/<text system version>/<CTRSDK version of sysmodule>/<system model number>

The codename can be set to either PBOS (Production BOSS?) or DBOS (Development BOSS?) depending if the console is a retail unit. As of system version 11.17, the user agent version is hardcoded to 8.0 and the CTRSDK version is set to 62452 (0xF3F4).

No user-agent is used for plaintext HTTP requests with SpotPass.

Titles Spotpass usage

Title	Description
Home Menu	Home Menu uses SpotPass for system notifications, and for uploading data from home-menu shared extdata.
System Settings	System Settings uses SpotPass for uploading data, with this URL: https://npul.c.app.nintendowifi.net/p01/recv/<RegionID>/sendcfg This RegionID is separate from the RegionIDs home-menu uses.
?	Unknown log data is uploaded with this URL: https://logus-p.est.c.app.nintendowifi.net/LogServer_us_live/Upload

Automatic System Update Download

See Automatic System Update Download.

BOSS Sysmodule Savegame

See BOSS Savegame

Content Container

SpotPass content must use this container to encrypt the payload and sign it, for content downloads. The cleartext content is stored in extdata. The format of these headers is big-endian.

BOSS Header

Offset	Length	Description
0x0	0x4	Magic Number "boss"
0x4	0x4	Magic Number 0x10001
0x8	0x4	Big-endian filesize
0xC	0x8	u64 serial number (?)
0x14	0x2	Must always be 0x1
0x16	0x2	Padding
0x18	0x2	Content header hash type, always 0x2 for SHA-256
0x1A	0x2	Content header RSA size, always 0x2 for RSA-2048 (X<<7)
0x1C	0xC	First 12 bytes of the Initialization Vector (IV)

Data following the BOSS header is encrypted with AES-CTR. The AES key that is used is stored in keyslot 0x38. The first 12 bytes of the IV are from offset 0x1C of the header, while the last 32-bit integer of the IV in big-endian is 0x1. The IV from the header is random per file, and an unique random IV is used each time the content is updated. The cleartext data begins with the content header.

The 64-bit number at 0xC may be a serial number which is increased every time someone requested to sign and create a boss container for a file. The 3DS sees the downloaded file as new if this number is different from the previous download (Doesn't matter if the number is bigger or smaller).

The boss system module v13314 begins at address 0x0010eb98 with the function for parsing the BOSS header.

Content Header

Offset	Length	Description
0x0	0x10	?
0x10	0x2	Number of payload contents (Payload Content Header + Payload)
0x12	0x20	SHA-256 hash
0x32	0x100	RSA-2048 signature over the above hash

The first 0x10-bytes are all-zero except the first byte which is usually 0x80. It's unknown what the first 0x10-bytes are used for.

The 16-bit value at 0x10 tells how many payload contents follow after this the content header. For example there can be a downloaded file for a game followed by a message for the news system module.

The hash at offset 0x12 hashes the 0x12-byte data at offset 0x0 followed by a zero u16. The RSA signature is signed by Nintendo. Following this header is the actual content payload, which is written to a cleartext file under the extdata /boss directory.

Payload Content Header

Offset	Length	Description
0x0	0x8	ProgramID
0x8	0x4	Usually zero?
0xC	0x4	Content datatype, used for filtering with BOSSU:GetNsDataIdList. Usually 0x10001? (observed 0x20001 in eShop strings)
0x10	0x4	Size of the payload after this header
0x14	0x4	NsDataId, used for generating the extdata filepath.
0x18	0x4	Probably some version field for the payload
0x1C	0x20	SHA-256 hash
0x3C	0x100	RSA-2048 signature over the previous SHA-256 hash

This signature is signed by Nintendo with the same key-pair as the content header.

The hash at offset 0x1C hashes the 0x1C-byte data at offset 0x0 followed by a zero u16, followed by all of the remaining cleartext data following this header(the actual content data).

The downloaded boss data is written in the following format to extdata. The file name that is generated might be Base85/Ascii85 encoded. First an extdata header in the following format

Offset	Length	Description
0x0	0x1	Size of header including this field. Always 0x18
0x1	0xB	Usually zero?
0xC	0x4	Unknown
0x10	0x4	Download date in format: Bit 0-5 = day, Bit 6-9 = month, Bit 10-20 = year
0x14	0x4	Usually zero? Padding?

Followed by the Payload Content Header without the hash and signature (first 0x1C bytes) and the actual payload.

Tools

• BossDecryptor3DS Decrypts an encrypted boss container
• BossEncryptor3DS Builds and encrypts a file into a boss container