Security was perceived by some in the first days of GSM as an unnecessary expense. Certainly, initially, all involved considered protection of user data from eavesdropping as more important than authentication of the user, though some questioned whether the perceived complexity of introducing encryption over the radio interface was justified. However, as fraud losses from cloning of analogue phones rocketed in the US and the UK, as the Dutch PTT withdrew all its NMT phones so a form of authenticat