This program allows you to extract your Nintendo Switch's SSL client certificate from a PRODINFO dump (Atmosphère stores these as sd:/atmosphere/automatic_backups/SERIAL_PRODINFO.bin).
DO NOT SHARE THIS FILE WITH ANYONE. THIS FILE WILL LET SOMEONE IMPERSONATE YOU ON NINTENDO SWITCH ONLINE AND POTENTIALLY GET YOU BANNED. KEEP IT SAFE.
You will need prod.keys; this can be dumped with Lockpick_RCM - it should be stored in ~/.switch/ or in the same directory as the program.
This tool uses .NET - on Windows you'll need to use the EXE, and the DLL or main executable on macOS/Linux.
NxCertDump.exe PATH_TO_PRODINFO or ./NxCertDump PATH_TO_PRODINFO - you may be able to drag and drop the PRODINFO bin onto the EXE on Windows.
The certificate will be dumped to nx_tls_client_cert.pfx - the password for the file will be switch.