Week 8 notes

Created Tuesday 30 June 2020

Privacy - 3 parts

  1. Secrecy (todays' topic)
  2. Anonymity (next week)
  3. A belief in the first two

Encryption

A sends message to B without C eavesdropping (C your way out?)

Cipher - "system"
Key
Ciphertext - "gibberish"
Cleartext - "the message"

Steganography

Encryption- better? It's not "you can't find the message" - it's "yeah, you have a copy but you STILL can't read it. So THERE!"

(private key) (public key)
[huge prime 1 x huge prime 2] = [superhuge composite]
easy ----------->
<---------------------nearly impossibly hard

"The bookstore method" - "One-time pad"

...but what if you CANT meet?

Phil Zimmerman "Pretty Good Privacy" or PGP

Phil went to jail (for a very short time)
...so why was he QUICKLY freed?

It's the other thing you can do with these keys - a weird reverse:
Instead of -
Locking with PUBLIC, unlocking with PRIVATE. (secret messages)

Locked with PRIVATE, unlocked with PUBLIC. (only I could have locked it — and therefore this is authentication)



Hashing

how to store passwords without storing passwords:
Remember — encryption yields "gibberish" --- UNIQUE

Like encryption, except:

  1. The "gibberish" is short
  2. You CANT decrypt it (ideally)
password = $MRNFIEFIJ@ifnjdfieuc92
MuchB3tterpasswordTAC0S = $KNFWIHIH$F

00000kdf3ouirfnjd














Backlinks: FSU Courses:LIS5411