Cissp Lesson 5

Front 1

Cryptanalysis

Back 1

Breaking or cracking the code and deciphering the data without authorization

Front 2

Cryptosystem

Back 2

A system for encoding and deciphering data.

Front 3

Decipher

Back 3

To decode the data

Front 4

Encipher

Back 4

To code the data

Front 5

Keyspace

Back 5

The group of numbers used to create a key.

Front 6

Non-repudiation

Back 6

Ensuring that the message sender is tracked and stored as having sent the message.

Front 7

Work Factor

Back 7

Estimated amount of work it would take to break the code.

Front 8

What are the 4 primary goals of cryptography?

Back 8

Confidentiality, Integrity, Authentication, and non-repudiation.

Front 9

Differential Cryptanalysis

Back 9

Compares two plain text data sets suring encryption to determine probably keys. Often used against block ciphers.

Front 10

Factoring

Back 10

Attempting to determine the prime factors of the keys.

Front 11

Linear Cryptanalysis

Back 11

Compares known plain text and ciphertext to determine probably keys

Front 12

Man-in-the-middle

Back 12

Intercepting messages between the sender and receiver

Front 13

Meet-in-the-middle

Back 13

Compares known plaintext and keys to intercepted encrypted text.

Front 14

Substitution

Back 14

A method of encoding data that uses the alphabet and each letter's associated numbers. Predetermined pattern.

Front 15

Ceaser Cipher

Back 15

Common form of substitution. Moves each letter 3 places forward in relation to its number.

Front 16

Polyalphabetic Cipher

Back 16

Uses multiple alphabets to encode data. (i.e. vigenere cipher)

Front 17

Transposition

Back 17

A method of encoding data that scrambles the letters of the message. a/k/a - Permutation

Front 18

Concealment Cipher

Back 18

A predetermined key or groups of words used to decode a message, such as reading only every fourth word.

Front 19

Running Key Cipher

Back 19

Using some predetermined set of actions taken to decode a message.

Front 20

Steganography

Back 20

Photographs or other digitial media used to hide messages.

Front 21

Symmetric Key Cryptography

Back 21

A method of encoding data that uses a single key. Used by both sender and receiver. Good to use with large amounts of data and is faster than Asymmetric

Front 22

Key Escrow

Back 22

Form of symmetric key cryptography used by law enforcement. Third party agency maintains the key.

Front 23

Clipper Chip

Back 23

An encryption chip for digital voice communications that automatically encrypts and decrpyts.

Front 24

Block Cipher

Back 24

An encryption method that breaks the message into blocks of data bits. Each block is encoded.

Front 25

Stream Cipher

Back 25

An ecryption method that breaks the message into a stream of single bits. Each bit is encoded. Slow method

Front 26

Data Encryption Standard (DES)

Back 26

56 bit cipher key for symmetric key encryption. Remaining 8 bits are used for parity, performed through 16 rounds. Susceptible to brute force attacks

Front 27

Triple DES (3DES)

Back 27

Uses 112 bit cipher key for symmetric key encryption. Encrypts message 3 times.

Front 28

Advanced Encrption Standard (AES)

Back 28

Uses Rijndael Block Cipher. Incorporates variable block cipher and key lengths. Uses a key size of 128.192, or 256. Approved by government

Front 29

Name the 4 modes of DES

Back 29

1. Cipher Block Chaining(CBC) - Most common. XORs an initialization block.
2. Cipher feedback(CF) - uses stream cipher
3. Electronic Code Book(ECB) - Uses Block ciphering
4. Output Feedback(OF) - Easy to break, XORs plain text

Front 30

Name the 3 modes of 3DES

Back 30

1. DES-EDE2 - Encrypt with one key, decrypts with another, encrypts with the first key again.
2. DES-EEE2 - Encrypts with one key, encrypts with a 2nd key, encrypts with the first key
3. DES-EEE3 - Encrypts with one key, encrypts with a 2nd key, encrypts with a 3rd key.

Front 31

Rijndael Block Ciper

Back 31

Uses both variable block and key lengths determined by the implementation. The lengths can be either 128,192, or 256.

Front 32

Blowfish

Back 32

Block cipher with block lengths, encrypted thru 16 X of 64 bits and key lengths up to 448 bits.

Front 33

International Data Encryption Algorithm (IDEA)

Back 33

Block cipher with block lengths of 64 bits divided into 16 bit units and encrypted 8 X. key lengths of 128 bits

Front 34

RC5

Back 34

Block cipher with variable block and key lengths and as well as encryption iterations

Front 35

RC6

Back 35

Block cipher based on RC5. Uses a min. 128 block size and 2 working registers to comply with AES

Front 36

Twofish

Back 36

Block cipher with 128 bit block lengths, encrypted 16 X and key lengths up to 256 bits.

Front 37

Asymmetric Key Cryptography

Back 37

A method of encoding information that uses 2 keys and a one-way function. Public key encrypts, private key decrypts. can perform authenticatoin and non-repudiation. a/k/a public key cryptography

Front 38

Open Message

Back 38

Encrypts message with private key, provides authentication only.

Front 39

Secure Message

Back 39

Encrypts the message with public key, provides confidentiality only.

Front 40

Signed and Secure Message

Back 40

Encrypts the message with private key and then with public key, provides authentication and confidentiality

Front 41

Message Digest(Message Hash)

Back 41

Cryptographic data that verifies the contents of a message that has not been altered.

Front 42

What is the difference between keyed and non-keyed message digests?

Back 42

Keyed - original message combined with a secret key. (MACs)
Non-Keyed - original message hashed without any other mechanisms(MICs and MDCs)

Front 43

Name some Message Digest Formats

Back 43

Message Digest 5 (MD5)
Secure Hash Algorithm(SHA)
Hashed Message Authentication Code (HMAC)

Front 44

Characteristics of a message hash

Back 44

1. Set length signature is created from variable length input.
2. Slight change in orginal creates great difference in result signatures.
3. Chances of 2 differing input values produce the same output signatures are low.

Front 45

Asymmetric key algorithms

Back 45

1. Diffie-Helman - requires key agreement
2. El Gamal - Functions on the encryption and digital signature. Often operates slowly.
3. Elliptic Curve Cryptosystem(ECC) - Often difficult to implement but capable to functioning with limited resources such as power and bandwidth.
4. Merkle-Hellman Knapsack - Applying weights to each set of items where the total defines the items in the knapsack. Used w/ trapdoors to one-way functions.
5. RSA - Functions on the encryption, digital signature, and key exchange.

Front 46

Public Key Infrastructure(PKI)

Back 46

Keys are created on the PC. Designed to address remote users and their data transmissions. common for e-commerce.

Front 47

Digital Signature

Back 47

Validates identity of sender. approved by NIST via SHS

Front 48

Name 4 Email Security Methods

Back 48

1. Pretty Good Privacy(PGP) - uses PGP keys only
2. Privacy Enhanced Mail(PEM) - can use various keys
3. Multipurpose Internet Mail Extension(MIME) - good choice for internal and standalone. No inherent security measures
4. Secure/MIME(SMIME)

Front 49

Name 5 Internet Security Methods

Back 49

1. Internet Security Protocol(IPSec) - server to server, remote access, network protection.
2. Secure Electronic Transaction(SET) - transmitting credit card data
3. Secure Hypertext Transport Protocol(SHTTP) - Protects single pages
4. Secure Shell(SSH-2) - remote access over the network.
5. Secure Socket Layer(SSL) - client to server authentication (HTTPS)

Front 50

2 Different protocols for IPSec

Back 50

1. Authentication Header(AH) - provides authentication
2. Encapsulating Security Payload(ESP) - whole suite of security