The original researcher published about this in August of this year [1], a year after reporting it, titling the report "Defrost the Food", which the attackers apparently took to be a good suggestion.
As the firmware is open for anyone to download [2], blurring the affected function seems more like an invitation to find out more. I know I was curious when the news about the fridges in France broke. The function's actually called "check_code_of_the_day", and this is the implementation:
uchar check_code_of_the_day(LPCTSTR pass) {
uchar uVar1;
LPCTSTR pass_local;
DATE_STRUCT date;
INT32 tothex;
INT32 hex;
UTF8_STR buff;
Get_syst_current_tds(&date);
ftext_s(buff,0x1ff,"%02d%02d%02d%02d",date.month,date.day,date.year,date.month);
sscanf(buff,"%lx",&tothex);
ftext_s(buff,0x1ff,,date.day);
sscanf(buff,"%lx",&hex);
tothex = __aeabi_idiv(tothex,hex);
ftext_s(buff,0x1ff,"%05ld",tothex % 100000);
if ((((*pass == buff[0]) && (pass[1] == buff[1])) && (pass[2] == buff[2])) &&
((pass[3] == buff[3] && (pass[4] == buff[4])))) {
uVar1 = '\x01';
}
else {
uVar1 = '\0';
}
return uVar1;
}
[2] https://www.danfoss.com/en-us/service-and-support/downloads/...