Summary
In this chapter, we began with a review of the evolution of symmetric encryption. We saw how IBM played a pivotal role in the early development of encryption, which was designed to protect consumer data. We learned how Horst Feistel and the IBM scientists designed the Feistel cipher. This then led to the development of Lucifer, which was an immediate precursor to DES.
We then discovered how symmetric encryption works, and discussed the development of DES. We saw how scientists were concerned that someone could launch a brute-force attack on DES, because of the short key. This concern led to the adoption of AES. We then dissected the main transformations of AES. In addition to DES and AES, we learned about other symmetric algorithms, along with a discussion on how subkeys are generated.
We compared the difference between block and stream ciphers and evaluated the different symmetric-encryption operating modes. We finished with a discussion on how we secure 802.11 transmissions...
