Encryption - I

Chapter 1,2 page 1-12

Terms & examples: cryptography, cryptanalysis

Encryption method vs key, key size

Brute force attack –aka exhaustive search

Shift is a more descriptive name for Caesar's cipher.

 Example: Hide birthday plans from an 8 year old.

Try decrypting this: B K N V M HR BNLHMF ZS SVN

Hint first few char:  C L O W N

another shift & 3 shuffle encryptions —decryption included.

		Encryption – I I				Chapter 1,2 page 1-12
		Universe of Keys

Shuffle's random encrypted alphabet table stops brute force attacks

 but cryptanalyst breaks encryption using letter frequency counts.

 3 shuffle encryptions—decryption solution included.

old but still charming letter counter

Encryption –I I – Universe of Keys

If you haven't noticed, this Simple Password has a substantial

weakness, especially for a short .

 The placement of letters not included in the password are in

 alphabetical order.→Good encryption requires good random.

		Encryption – I I I				Chapter 2 pages 13-18
		MultiShift

Each letter in makes a shifted encrypted alphabet.

 example: M Y P A S S W O R D makes 10 shifted alphabets.

 Infinite number of keys; provable absolute security if used as one-time-pad.

 MultiShift is a more descriptive name for Vigenere Cipher.

  Wikipedia Vigenere & 2 Vigenere cryptanalysis sites

.pdf from N. Kentucky U.   Interactive example from U of Rhode Island

  DES & AES 56, 128, 256 bit   sizes —history, choosing, attacking.

 Cryptographic fingerprints used to verify authenticity.

 

  Link to book chapters below

Chapter

5  DES isn't strong anymore

7  Secret  assurances & sharing

8  Problems with secret  sharing

§ some secret  mechanics…

3  Shell games with text (transpostion ciphers)

4  Hiding letter patterns (diffuse & confuse)

 

Hands-on demos secret   gotchas

· Encryption can be purposely & fraudenlty corrupted

· Cryptographic message fingerprints  can identify fraud

· A cipher mode that can expose you to attack

  Link to book chapters below

Chapter

9  Public key pioneers

10  How  works

12  How  works (Digitial Signatures)

15  Comparing  

16  Distributing s with Digitial Certificates

17  Certificate Authority (x.509 centralized control)

18  Pretty Good Privacy (distributed trust)

§ some  mechanics…

11  Making  pairs

13  Using in fingerprints

14  Fingerprint (hash, digest) assurances

 

Hands-on  demos