Raw dumps from game cartridges. They work on flashcarts (like Gateway) but will not load in emulators without a decryption key.
Always cross-reference a new site with the r/roms "Safe List" before downloading. Can I Decrypt My Own ROMs? where to find decrypted 3ds roms
The safest and only legally compliant way to get decrypted 3DS ROMs is to create them from your own physical collection. To do this, you need a Nintendo 3DS console with custom firmware (CFW) installed via Luma3DS and a homebrew tool called . Raw dumps from game cartridges
If you can only find encrypted .3ds files online, you can decrypt them yourself on your PC using a lightweight community tool called . Can I Decrypt My Own ROMs
When downloading files from the internet, there's always a risk of malware. Stick to well-known sites, and consider using a reputable antivirus program.