With 4G LTE (and which replaces the legacy Signalling System no. 7 (SS7) protocol), the encryption method used is SNOW 1.0/2.0/3G . These are synchronous stream ciphers developed by Thomas Johansson and Patrik Ekdahl (Lund University). SNOW 3G has been selected for the 3GPP encryption algorithms UEA2 and UIA2.5 Mar 2019