Question

As we have explained throughout the trimester, the textbook AES and RSA are not secure (with respect to chosen-plaintext attack). But we can convert textbook AES and RSA to a secured version using a technique called randomized encryption. Applying this technique to AES, we need to have an initialization vector (IV). Say we have a message m with 128 bits, show how to encrypt m with secured AES. Explain why IEEE 802.11 (i.e., WEP) is not secure due to the inappropriate usage of an IV.

Answer 1

How to encrypt with the help of AES?

• The most basic encryption algorithm that is been used is AES(Advanced Encryption Standard). It is one of the most standard algorithms which is been trusted a lot and follows the standards that are been set by the American Standards.
• The main advantage of the algorithm is that it uses very less RAM and works very efficiently. It can be used for many variants which include 128,192,256 bits.
• In AES, there are basically 10 rounds which are been used for 128-bit keys. The same key is used for encryption as well as decryption of the data. According to the data, until now there are no attacks which are been discovered to be effective in AES.
• Hence, it remains the safest algorithm for encryption and is been used on certain devices and transmission technologies. It is mostly used for wireless connections authentication.
• While going on with the encryption one must always be sure about what is being used and what is to be encrypted. The user base is going to handle the data.
• The more important the data, more security for the data. This means that the algorithm like Triple DES etc. must be used if data is too confidential and can harm a lot of people if leaked.
• There are also certain factors to which the system relies on. Hence, the algorithm must be full proof of attacks and the security must be to the ultimate level.

Explain why IEEE 802.11 is not secure?

• The main reason behind IEEE 802.11 not secure are as follows:
  • The low complexity of the encryption policy
  • It is the older version of encryption used to encrypt passwords in the IEE 802 technology.
• The obvious reason is that the Initialization Vector (IV) can be reused. Hence, resuing the keys is one of the major weakness which is affecting the security systems which make use of IEE 802.11 (WEP).
• The IV is also too short in the case of IEE 802.11(WEP). It only can make the attacker wait for a long time to crack the security but is surely crackable.
• WEP makes use of weak keys and is very much susceptible to launch an attack on and also the master keys are being used for generating most of the temporary keys.

Hence, these are the reasons why IEE (802.11) is not secure.