Lockpick_RCM

Lockpick_RCM is a bare metal Nintendo Switch payload that derives encryption keys for use in Switch file handling software like hactool, hactoolnet/LibHac, ChoiDujour, etc. without booting Horizon OS.

Due to changes imposed by firmware 7.0.0, Lockpick homebrew can no longer derive the latest keys. In the boot-time environment however, there is no such limitation.

Usage

• It is highly recommended, but not required, to place Minerva on SD from the latest Hekate for best performance, especially while dumping titlekeys - the file and path is /bootloader/sys/libsys_minerva.bso
• Launch Lockpick_RCM.bin using your favorite payload injector or chainloader
• Upon completion, keys will be saved to /switch/prod.keys and titlekeys to /switch/title.keys on SD
• This release bundles the Falcon keygen from Atmosphère-NX

Mariko-Specific Keys

Mariko consoles have several unique keys and protected keyslots. To get your SBK or the Mariko specific keys, you will need to use the /switch/partialaes.keys file along with a brute forcing tool such as https://files.sshnuke.net/PartialAesKeyCrack.zip. The contents of this file are the keyslot number followed by the result of that keyslot encrypting 16 null bytes. With the tool linked above, enter them in sequence for a given keyslot you want the contents of, for example: PartialAesKeyCrack.exe <num1> <num2> <num3> <num4> with the --numthreads=N where N is the number of threads you can dedicate to the brute force.

The keyslots are as follows, with names recognized by hactool:

• 0-11 - mariko_aes_class_key_xx (this is not used by the Switch but is set by the bootrom; hactoolnet recognizes it but it serves no purpose)
• 12 - mariko_kek (not unique - this is used for master key derivation)
• 13 - mariko_bek (not unique - this is used for BCT and package1 decryption)
• 14 - secure_boot_key (console unique - this isn't needed for further key derivation than what Lockpick_RCM does but might be nice to have for your records)
• 15 - Secure storage key (console unique - this is not used on retail or dev consoles and not recognized by any tools)

So if you want to brute force the mariko_kek, open your partialaes.keys and observe the numbers beneath keyslot 12. Here's an example with fake numbers:

12
11111111111111111111111111111111 22222222222222222222222222222222 33333333333333333333333333333333 44444444444444444444444444444444

Then take those numbers and open a command prompt window at the location of the exe linked above and type: PartialAesKeyCrack.exe 11111111111111111111111111111111 22222222222222222222222222222222 33333333333333333333333333333333 44444444444444444444444444444444 and if you're on a powerful enough multicore system, add --numthreads=[whatever number of threads], ideally not your system's maximum if it's, for example, an older laptop with a low-end dual core CPU. On a Ryzen 3900x with 24 threads this generates a lot of heat but finishes in about 45 seconds.

These keys never change so a brute force need only be conducted once.

This works due to the security engine immediately flushing writes to keyslots which can be written one 32-bit chunk at a time. See: https://switchbrew.org/wiki/Switch_System_Flaws#Hardware

Building

Install devkitARM and run make.

Massive Thanks to CTCaer!

This software is heavily based on Hekate. Beyond that, CTCaer was exceptionally helpful in the development of this project, lending loads of advice, expertise, and humor.

License

This project is under the GPLv2 license. The Save processing module is adapted from hactool code under ISC.