How can I use encrypted .sav files from 3DS flash cards?

Hello,

I am using the latest Citra nightly build on my computer (05. Feb. 2021)
https://github.com/citra-emu/citra-nightly/commit/6b2e7b7

But I have many encrypted .sav files from 3DS flash cards for example from Gateway 3DS, Sky3DS, DStwo+ etc…
https://wiki.gbatemp.net/wiki/3DS_Flashcart_Comparison

The problem these 3DS flash cards don’t work anymore because they are broken. But I have stored .sav files on my PC. How can I use these .sav files in Citra?

Is there also a easy way (GUI method) to convert the .sav files seamlessly to Citra compatible save file?

This is not currently supported in citra. I recommend for the 3DS flash card users to follow this github report when it is added in citra.