Hacking Question about Decrypting Title Keys

[FF777]

I bought a game from eshop and wanted to create a decTitleKeys.bin of it for absolutely no reason at all ＞＿＞

Different posts say to do that, I use Decrypt9 > TItlekey Options > Titlekey Decrypt

But when I go there, it gives me the options of either "Titlekey Decrypt (file)" or "Titlekey Decrypt (SysNAND)"..

The posts never specify which one I should use..
And I know the game data is actually saved on the SD card..

I tried using the "(SysNAND)" option, and it seemed to work but part of the log says: "Decrypted 16 unique Titlekeys. Skipped 254 useless Titlekeys."
Well, I have more than 16 games installed on my 3DS.. So is it actually including the game that I recently purchased?..

If I am supposed to use the "(file)" option instead, which file do I select?.. And how do I make sure the titlekey for that game's update is included?..

 

[offpir]

Here is the decrypt9 readme:

https://github.com/d0k3/Decrypt9WIP/blob/master/README.md

Titlekey Options
This category includes all titlekey related features. Decrypted titlekeys (decTitleKeys.bin) are used to download software from CDN via the included Python script cdn_download.py and PlaiCDN. Encrypted titlekeys are used, for the same purpose, by FunKeyCIA. You may also view the (encrypted or decrypted) titlekeys via print_ticket_keys.py.

• Titlekey Decrypt (file): First, generate the encTitleKeys.bin via the included Python script dump_ticket_keys.py and place it into the /files9/ work folder. This feature will decrypt the file and generate the decTitleKeys.bin, containing the decrypted titlekeys.
• Titlekey Encrypt (file): This feature takes a decTitleKeys.bin file and encrypts it to encTitleKeys.bin. This is useful to convert between the two formats, to make sure you have the right format for the tools you use.
• Titlekey Decrypt (SysNAND): This will find and decrypt all the titlekeys contained on your SysNAND, without the need for additional tools. The decTitleKeys.bin file will be generated on your SD card.
• Titlekey Decrypt (EmuNAND): This will find and decrypt all the titlekeys contained on your EmuNAND, without the need for additional tools. The decTitleKeys_emu.bin file will be generated on your SD card.
• Titlekey Dump (SysNAND): This will find all the titlekeys contained on your SysNAND and dump them, without the additional step of decryption, to encTitleKeys.bin.
• Titlekey Dump (EmuNAND): This will find all the titlekeys contained on your EmuNAND and dump them, without the additional step of decryption, to encTitleKeys_emu.bin.
• Ticket Dump (SysNAND): Use this to dump all tickets found inside your SysNAND ticket.db file. Naming scheme for tickets is (commonkey index)-(console id)-(title id).tik. Commonkey index is typically 0 for eShop titles and 1 for system titles, a console id of zero for eShop titles typically means a forged (= non genuine) ticket. Dumped tickets are installable via FBI.
• Ticket Dump (EmuNAND): Same as above, but uses the ticket.db file from your EmuNAND.

 

[gamecaptor]

I too would like to create a decTitleKey.bin from a title I recently purchased from the eShop for no apparent reason. Found this: https://github.com/ihaveamac/3DS-rom-tools/wiki/Dump-tickets-and-titlekeys-from-a-3DS

My question is how do I figure out Title ID of said title?

 

[FF777]

I found out the "Titlekey Decrypt (SysNAND)" is probably the one you need.. Every time I've used it, it has included the titlekeys that I wanted included..

After I buy a game, I go in to FBI and go to "Titles", and let it load all the titles I have on my 3DS, then I scroll down and search for the game (or update or DLC) I just bought, and it will show you the TitleID..

After you go to decrypt9 and select the "Titlekey Decrypt (SysNAND)" option, it will create decTitleKeys.bin in the /files9/ directory on your SD card..
If you want to make sure that file contains the TitleID that you want it to have in it, what you can do is open that file (decTitleKeys.bin) in a hex editor on your computer, and it is really easy to spot the different titleIDs in there.. The first titleID starts at offset 0000:0018, next one is at 0000:0038, next is at 0000:0058 (just keep adding 20.....although your eyes will already see them easily any way, because pretty much all titleIDs start with 000400)..

 

[gamecaptor]

Ah, I didn't think about looking in FBI (I forgot it lists them out).

So now I'm confused as to where from that file I can find the Title Key?

Never mind, I found this thread and it explained it all: https://gbatemp.net/threads/how-to-dump-and-backup-eshop-games-and-dlc.375586/