Each of the 128-bit secret key K is used only once in each round. In the different rounds, each bit is used in different ways and also in different parts. Sometimes then, the values are altered by the use of constants that modify the key. Are used the constants C1, C2,…, C8 in scheduling the mobile recharge vodafone key to avoid the existence recharge api of a recurrence relation between the keys of a certain consecutive rounds.

This property is useful to prevent chosen attacks that are faster than recharge api exhaustive search. Although the regularity and symmetry in the schedule of the key is not a point of weakness for the algorithm, it is good to avoid stretch short keys, in a very symmetrical. In particular, it is good to avoid the elongation of a key with the simple addition of zero bits, not to facilitate possible attacks. This, however, is only a precautionary measure since it was not found any weak key.

A differential recharge api type

For the recovery of the key K are possible various types of attacks. Their analysis led to the conclusion that you can retrieve a key in a KASUMI algorithm consists of only5 rounds (sometimes 6) while it seems impossible to recover the key when the rounds of KASUMI are eight. In particular, it has been Your Domain Name described chosen attack to recover the key SU5 round KASUMI. The attack requires about 238 carefully chosen plain texts and mobile recharge vodafone 280 operations.

This attack could be extended a6 round but not all gli8 round KASUMI algorithm. Were also taken into account the differential Visit Your URL attacks on the key and recharge api it was concluded that these types of attacks are possible only on an algorithm of KASUMI reduced to four or five rounds. An attack of this kind, on KASUMI reduced to four rounds, requires encryption of about 29 pairs of recharge api X and X properly selected and input respectively with the keys K and K* which differ by only one bit. The average complexity of this attack is approximately2 41.

Case just the encryption

Instead, if the rounds of KASUMI are five, the attack requires encryption average of3 217 pairs of plain texts suitably selected with an average complexity of about 236. E was recharge api calculated that if the key K was only 64 bits, the algorithm of KASUMI with only five rounds, would become vulnerable to an attack on the key differential. In fact, in this of plaint ext about 10 under two keys, with an attack that has a complexity of about. The objective of the statistical mobile recharge vodafone evaluation is to verify that KASUMI, f8 and f9 behave as random functions.

KASUMI has been subjected to the test of the snowball effect (avalanche effect) and to a test that would verify if it was capable of destroying the redundancies in the input. The algorithm KASUMI has passed both tests. In particular with recharge api the test snowball effect has been verified that with a fixed key, when it changes one of the 64-bit input KASUMI, also changes about half of the bits of the output, that is changing about 32-bit output.