%0 Journal Article %K Critical Infrastructure %K PBX %K PBX security %K PSTN %K Telephony %B Information & Security: An International Journal %D 2012 %G eng %N 1 %P 89-97 %R http://dx.doi.org/10.11610/isij.2807 %T PRETTY (Private Telephony Security) - Securing the Private Telephony Infrastructure %V 28 %8 2012