KASUMI is a block cipher used in UMTS, GSM, and GPRS mobile communications systems. In UMTS, KASUMI is used in the confidentiality (f8) and integrity algorithms (f9) with names UEA1 and UIA1, respectively.[1] In GSM, KASUMI is used in the A5/3 key stream generator and in GPRS in the GEA3 key stream generator.
In January 2010, Orr Dunkelman, Nathan Keller and Adi Shamir released a paper showing that they could break Kasumi with a related key attack and very modest computational resources; this attack is ineffective against MISTY1.[5]