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CISSP > Cryptography > Flashcards

Cryptography Flashcards

(93 cards)

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1
Q

IPsec SA

A

Security assocation: simplex connection used to negotiate ESP or AH

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2
Q

difference between hashing and encrypting?

A

Hash is a one way function; Encryption assumes someone will decrypt

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2
Q

substitution

A

replaces one character for another (providing confusion)

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3
Q

modular math

A

26 letters in alphabet. Therefore, Y + C = B - or - 25 + 3 = 28 or 26 remainder 2 and 2 = B

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3
Q

scytale

A

parchment wrapped around a rod, written on, then unwrapped

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3
Q

triple DES

A

applies single DES three times per block; slow and complex

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4
Q

RC5

A

symmetric, 0 to 2040 bit key, 32, 64, 128 bit blocks

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5
Q

linear cryptanalysis

A

plaintext attack where the cryptanalyst finds large amounts of plaintext/ciphertext pairs created with the same key

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5
Q

IPsec

A

Internet protocol security: suite of protocols that provide a cryptographic layer to both IPv4 and IPv6; used to establish VPNs; overly complex with multiple overlapping parts

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6
Q

ECC

A

elliptic curve cryptography: leverages one-way function that uses discrete logarithms as applied to elliptic curves; strong; less computational resources; used in low power devices

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6
Q

AH

A

authentication header: provides authentication and integrity (no confidentiality); protects against replay attacks

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7
Q

CFB

A

cipher feedback: stream cipher; like CBC only is a stream mode using feedback (chaining in stream mode); uses initialization vector; errors propogate

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7
Q

differential cryptanalysis

A

seeks to find the difference between related plaintexts that are encrypted

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7
Q

escrowed encryption

A

thrid-party organization holds a copy of the public/private key pari

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8
Q

permutation

A

aka transposition; provides diffusion by rearrnagin the characters of the plaintest, anagram-style

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8
Q

known plaintext

A

knowing the plaintext and cipher text allows you to figure out the key

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8
Q

key escrow

A

a copy is retained by a third-pary org, often for the purposes of law enforcement

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9
Q

ciphertext

A

encrypted message

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9
Q

Single DES

A

encrypts 64 bits blocks of data with 56 bit key using 16 rounds of encryption

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10
Q

HAVAL

A

hash of variable length: hash algorithm that craets message digests of 128, 160, 192, 224, 256 bit in length using 3,4, or 5 rounds

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10
Q

CA

A

certifiate authorities: issues digital certificates

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11
Q

rainbow tables

A

precomputed compliation of plaintexta dn matching ciphertexts; greatly speed up many tpes of password cracks

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12
Q

5 modes of DES

A
  1. ECB (Electronic Code book) 2. CBC (cipher block chaining) 3. CFB (Cipher feedback) 4. OFB (output feedback) 5. CTR (counter mode)
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14
Q

polyalphabetic cipher

A

uses multiple alphabets

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15
S/MIME
secure Multipurpose Internet mail extensions: provides a standard way to formal e-mail (leverageing PKI)
16
factoring
figuring out which two prime numbers multiplied provides an answer
16
collisions
when two documents hash to the same value
17
key clustering
occurs when two symmetric keys applied to the same plaintext produce the same ciphertext
18
algorithm
set of instructions
21
monoalphabetic cipher
uses one alphabet
21
CTR
Counter: like OFB; stream cipher; uses a counteruses initialization vector; errors don't propogate
22
secure hash algorithm
a series of hash algorithms; weak collision avoidance
23
IDEA
international data encryption algorithm: symmetric block cipher designed to replace DES; 128 bit key, 64 bit block; slow
24
CBC
cipher block chaining: block cipher; XORs previous encrypted block of ciphertext to next block of plaintext;uses initialization vector; errors propogate
24
HMAC
hashed Message Authentication Code: combines a shared secret key with hashing; IPsec uses HMAC; two partices must pre-share secret key
25
blowfish
symmetric, 32 to 448 bit keys; 64 bit block; open algorithm
26
Diffie-Hellman
asymmetric pioneers; uses discrete logarithms to provide security, uses one-way factoring
27
steganography
science of hidden communication; hides info inside of other files such as images
28
cryptology
science of secure communications; encompasses both cryptography and cryptanalysis
29
SSL
secure sockets layer: brings power of PKI to the web
30
social engineering
it is what it is
31
twofish
symmetric, 128 to 256 bit key, 128 bit block
32
IPSec protocols
AH and ESP
33
key storage
organization that issued the publi/private key pairs retains a copy
34
PGP
pretty good privacy: brought asymmetric encryption to the masses; uses a web of trust model to authenticate digital certificates
36
OFB
output feedback: stream cipher; uses the previous ciphertxt as the subkey before it is XORd; uses initialization vector; errors don't propogate
37
COCOM
coordinating committee for multilateral expert controls: in effect from '47 to '94
38
PKI
public key infrastructure: leverages all three forms of encryption to provide and manage digital certificates
40
hash function
one-way encryuption using an algorithm and no key; no way to reverse the encryption
41
work factor
describes how long it will take to break a cryptosystem
42
vigenere cipher
polyalphabetic cipher
43
one-way function
math that is easy one way, but hard another. Ie 7 to the 13th power is easy to figure. 96,889,010,407 is 7 to what power is much, much harder
45
purple
stepping-switch device built with phone sitch hardware; later models were red and jade
47
chaining
seeds previous encrypted block into th enext block to be encrypted; destroys patterns in ciphertext
48
Wassenaar Arrengement
successor to COCOM; initiated in 1996; relaxed many restrictions on exporting cryptography
49
diffusion
order of the plaintext should be diffused or dispersed in the ciphertext
50
ORA
organizational registration authorities: authenticate the ID of a certificate holder before issuing a certificate to them
51
clipper chip
used skipjack algorithm; symmetrick cipher with 80 bit key; used in EES
53
symmetric encryption
Encryption that uses 1 key to encrypt and decrypt; aka "secret" key encryption; strengths include speed and cryptographic strength per bit of key
54
DES
data encryption standard: describes data encryption algortihm; federal standard symmetric cipher; 64 bit block, 56 bit key
56
plaintext
unencrypted message
57
Jefferson disks
sort of an early cipher disk, but not really used much
58
side-channel
use physical data to break a cryptosystem
59
ISAKMP
manages the SA creation process
60
AES
advanced encryption standard: 128 bit, 192 bit, 256 bit keys, 128 bit blocks; open algorithm, free to use
61
RC6
symmetric 128, 192, 256 bit key, 128 bit blocks
62
cipher disk
two concentric disks each with alphabet around perimeter; allows mono and poly alphabetic encryption
63
ElGamal
asymmetric algorithm using one way factoring
64
protocol governance
describes the process of selecting the right mothod (cipher) and implementation for the right job
65
birthday attack
used to create hash collisions
66
IKE
Internet Key exchange: negotiates the algorithm selection process for Ipsec
68
ECB
electronic code book: block cipher; simplest and weakest form of DES; no initialization vector or chaining; errors don't propogate
69
SPI
security parameter Index: identifies each simplex SA connection
71
three types of modern encryption
symmetric, asymmetric, hashing
72
codebooks
assign codewords for important things
73
assymmetric encryption
encryption that uses 2 keys; if you encrypt with one, you may decrypt with the other
74
TLS
transport layer security: successor to SSL
76
confusion
relationship between the plaintext and ciphertext should be as confused or reandom as possible
76
MAC
message authentication code: hash function that uses a key; provides integrity and authenticity
78
5 components of PKI
1. Certification authorities issue/revoke certs 2. Organization registration authorities vouch for binding between public keys and cert holder ID 3. cert holders that are issues certs and can sign digital docs 4. clietns that validate digital signatures and their cert paths from a know public key 5. repositories that store and make availabe certs and cert revocation lists
79
caesar cipher
simple rotation cipher
80
cryptanalysis
science of breaking encrypted messages (recovering their meaning)
81
book cipher
uses whole words from a well-known bok such as a dictionary; agree on page, line, word offset and source
83
cryptography
creates messages whoe meaning is hidden; can provide confidentiality and intregrity; can also provide authentication and non-repudiation
84
MD5
message Digest 5: 128 bit hash based on any input length
85
digital signatures
provide non-repudiation
86
brute force
generates the entire keyspace; effective attack against all key-based ciphers except one-time pad; only provably unbreakable form of crypto
87
known key
means the cryptanalyst knows something about the key, not cecessarily knows the key
88
implmentation attacks
exploit a mistake made while implementation a service, application, or system
90
CRL
certificate revocation list: list of certificates that have been revoked
91
ESP
encapsulating security payload: provides confidentiality by encypting packet data; may also provide authentication and integrity
92
XOR
exclusive Or: two bits are are the same, answer is true; if two bits are different, answer is false
93
meet-in-the-middle
encrypts on one side, decrypts on the other and meets in the middle

CISSP (11 decks)

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