i guess there is an llHMAC ,oops i was looking in the os functions :)
so instead of string sig = llSHA256String(ciphertext + "|" + ts + "|" + secret);
use
string sig = llHMAC(secret, msg, "sha256...
Nope, it's down for me as well.
I know from Lone that they were already unable to ever upgrade it to a newer version. Maybe it's completely broken now. Or it wasn't worth keeping alive with Lone bein...