
What is cryptography?
Cryptography is making information hidden so only intended receiver can read it.

What is confidentiality?
  prevents unauthorized disclosure of information
  symmetric and asymmetric encryption

What is integrity?
  provides assurance that method was not modified
  hashing, digital certs, digital signatures

What is availability?
  insuring resources are available to authorized users in a timely manner
  redundancy, fail over, raid, high availability clusters

What is authentication?
  the process of verifying that the sender is who they say they are
  bio metrics, encryption, digital certs, PIN

What is authorizaton?
  granting access based upon the need
  access control list (ACL), clearance level

What is accounting?
  act of collecting information on resource usage
  logging, auditing, monitoring

Encryption key storage
TPM

A certificate authority takes _______ actions in PKI
issues and signs all root certificates

A CRL is compromised of
public keys

SSH
deals with remote access/routers

TLS
maximum security between web browser and a web server


elliptic curve cryptography
is mostly used in embedded devices and produces higher strength encryption with shorter keys

cryptography's four primary functions
  confidentiality
  integrity
  authentication
  nonrepudiation

ensures only authorized parties can access data
(symmetric and asymmetric encryption)
confidentiality

data has not been modified in transit (hashing, digital signatures, digital certs)
integrity

verifying the sender is who they say they are (bio metrics, digital certs)
authentication

prevents denying of actions
nonrepudiation

process of converting readable text into unreadable series (hidden)
cryptography

practice of finding weaknesses in ciphers (finding the code)
cryptanalysis

result of encryption performed on plain text using an algorithm (disguised)
cipher text

steganography
hidden with graphics or sound files

substitute cipher
changes one character/symbol into another character/symbol

transposition cipher
changing positions of plain text letters within a sentence (scrambling letters)

stream cipher
data encrypted bitbybit (wireless)

block cipher
enciphers chunks of data, slower, stronger than stream

frequency analysis
the study of frequency of letters or groups of letters in a ciphertext

give a scenario of perfect forward secrecy
if someone steals your computer key, they can only crack the information for the part that was encrypted.

key stretching
 apart of key management
 the longer the key, the longer it will take to get hacked

steganography usage
  convert channel
  electronic watermarking (DRM)
  metadata

What is the difference between cryptography and steganography?
cryptography is the entire data, steganography is just a particular part of the data, image, sound channel.

exclusiveOR (XOR) operation
binary mathematical operation which compares two bits to produce an output

onetime pad
 unbreakable
 made up of random values and only used once


initialization vectors
 random values used with algorithms
 WEP & TKIP

three types of cryptography


symmetric
one key shared with both parties

asymmetric
two keys, public and private


hashing functions in order
 MD4
 MD5
 SHA (SHA1)
 SHA2
 SHA3
 RIPEMD
 RIPEMD160
 HAVAL
 Whirlpool

two separate inputs give the same
hash

birthday attack
if a certain amount of individuals are in a room, it is highly likely that at least two will share birthdays

brute force attack
every possible combination (there is no system that cannot be broken into)

dictionary attack
uses all words in the dictionary to reveal passwords

symmetric cryptogrpahy
 private key
 only one; both parties share same key

session key, secret key, shared key, private key, same key, single key
symmetric crytography

cons of symmetric cryptography
no way to verify who has it because it is shared

pros of symmetric crytography
 produces smaller file size
 faster

symmetric key algorithms
 DES
 3DES
 AES
 blowfish
 CAST
 rivest cipher
 IDEA
 skipjack
 SAFER

data encrypted standard (DES)
 56bit key
 easily broken
 lucifer

3DES (tripleDES)
 upgrade of DES
 168bit key

advanced encryption standard (AES)
 replaced DES
 key sizes: 128, 192, and 256 bits
 qualifies for top secret information
 rijndael

blowfish
 fastest of symmetric
 64bit


CAST
used with pretty good privacy (PGP) and email

pretty good privacy (PGP)
email


IDEA
used in PGP and email

skipjack
 developed by the U.S. National Security Agency (NSA)
 can check your emails without your knowledge
 LEAF


whole disk encryption
every bit of data is encrypted

software
 bitlocker
 windows and MACOS X
 checkpoint

asymmetric
 two keys, public and private
 public used by sender to encrypt, private used by receiver to decrypt

advantages of asymmetric
offers digital signatures, integrity check, key exchange, and nonrepudiation

disadvantages of asymmetric
slower than symmetric


el gamal
 based upon duffhellman
 encryption, digital signatures, key exchange
 DSA
 main drawback is performance

rivest, shamir, adleman (RSA)
 encryption, digital signatures, key exchange
 used in PGP (email)

elliptic curve cryptography (ECC)
 encryption, digital signatures, key exchange
 ECC 160bit is equal to 1024bit RSA key

what three items are used to create the signature
 email message
 hashing algorithm
 senders private key

digital signature process (sender)
 creates email message
 creates a message hash
 uses senders private key to encrypt hash

digital signature process (receiver)
 hashes received message
 uses sender's public key to decrypt message
 two hashes compared

