Computational Security correct answers Given limited computing resources, (pc power, amount
of time needed for calculations is great (ex: 200 yrs), the cipher cannot be broken
Unconditional Security correct answers No matter how much power and time are given, cipher
cannot be broken
Claude Shannon correct answers 1949 introduced idea of developing ciphers based on
Substitution and Permutation
Shannon's Idea correct answers forms the basis of modern block ciphers
According to Shannon: correct answers A cipher, which well combines Sub and perm elements,
may achieve confusion and diffusion, this, it is secure
Feistel Cipher Design Principles correct answers Increasing block size provides greater
security(reduces speed); Key size improves security (makes key searching harder, but may slow
cipher); Num of Rounds: increasing improves security, but makes it less efficient (typically 16
rounds); Sub-key Generation: greater complexity can make analysis harder (slows); Round
Function: greater complexity can make analysis harder (slows); Fast software en/decryption and
ease of analysis: are most recent concerns for practical use and testing
Data Encryption Standard (DES) correct answers issued in 70s, as an encryption standard, 64-bit
using 56 bit key
Advanced Encryption Standard (AES) correct answers Issued as standard in 2001, replacing
DES
What were DES and AES both designed to do correct answers to try and achieve confusiong and
diffusion using Sub and Perm operations
AES correct answers Replaced DES, encrypting 128 bit data (4 groups of 4 bytes), using
128/192/256 bit keys
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller FullyFocus. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.99. You're not tied to anything after your purchase.
