Well it's not as crap as the original GSM, but it wasn't designed in the open (so may be backdoored) and the progression of attacks at https://en.wikipedia.org/

Well it's not as crap as the original GSM, but it wasn't designed in the open (so may be backdoored) and the progression of attacks at https://en.wikipedia.org/wiki/KASUMI#Cryptanalysis https://en.wikipedia.org/wiki/KASUMI#Cryptanalysis doesn't really inspire confidence.