Short answers, pulled from the story.
Thomas Johansson and Patrik Ekdahl created the SNOW family of stream ciphers at Lund University. Their design centers on a 512-bit linear feedback shift register that feeds into a non-linear output state machine.
SNOW-V emerged as an extensive redesign published in 2019 to match high-speed requirements of 5G cellular networks. It generates 128 bits of output per iteration using Advanced Encryption Standard round functions implemented directly in hardware.
Early versions like SNOW 1.0, SNOW 2.0, and SNOW 3G utilize a shift register holding sixteen 32-bit words. Each iteration advances this register by 32 bits to produce 32 bits of output data through a 32-bit add-rotate-XOR transformation.
Reviewers discovered specific weaknesses during their analysis that prevented inclusion in the final suite of the NESSIE project. The authors responded by developing version 2.0 to address these identified flaws and improve performance metrics.
The resulting variant received the name SNOW 3G after designers modified the algorithm further to increase resistance against algebraic attacks. This version became the chosen stream cipher for UEA2 encryption algorithms within mobile telecommunications standards and serves as the basis for UIA2 integrity protection mechanisms used in 3GPP networks.