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CISSP Exam > Video Content Lesson 3 > Flashcards

Video Content Lesson 3 Flashcards

2
Q

Julius Caesar’s Cryptography was known as

A

ROT3 (Rotate 3 characters)

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3
Q

Famous German Encryption Machine

A

Enigma

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4
Q

Japanese Encryption Machine

A

Purple Machine

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5
Q

Current Goals of Cryptography

A 
Ensure Confidentiality (private messages stay private even during transmission)
Provide Integrity (ensure message hasn't been changed in transmission--digital signature does this)
Provide Authentication (Validates claimed identity of message's sender, uses encrypted challenge phrases to ensure other party knows appropriate key--similar to non-repudiation)
Provides Nonrepudiation (provides assurance that message came from who it says it came from, validates that message has not been spoofed)
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6
Q

Cryptographic Uses

A

Email
Protocols and standards (PGP Pretty Good Privacy; S/MIME Secure/Multipurpose Internet Mail Extension; IPSec Internet connection security; SSL/TLS Secure Socket Layer/Transport Layer Security)

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7
Q

Concepts and Methodologies

A 
Cryptography Terms
Tranposition Cipher
Subtitution Cipher
Cipher Categories
Cipher Process
Symmetric Algorithms
Asymmetric Algorithms
Message Authentication
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8
Q

Cryptography Terms

A

plaintext-Original message- readable
Ciphertext-encrypted message- only readable if first decrypted
Cipher-process of rearranging or altering a plantext message so it is unreadable

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9
Q

Tranposition Cipher

A

Start with a keyword
List the ordinal values, based on a letter’s position in the alphabet
Write plaintext message in tabular form
Read individual columns

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10
Q

Substitution Cipher

A

replaces each character of a plaintext message
All that is needed is a table of plaintext characters and their associated substitute characters
A simple algorithm can be created
Both sender and receiver must use same
One-Time Pad (OTP) (only known unconditionally secure cipher)
Never reuse a OTP

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11
Q

Cipher Categories

A 
Stream Cipher (each character is encrypted-example substitution cipher)
Block Cipher (works on a chunk/block of plaintext-example transposition cipher)
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12
Q

Cipher Process

A

One-way function (function that is relatively easy to use to produce output values AND impossible (or nearly so) to deduce the input values from the output values)
Algorithm is sequence of steps used to encrypt plaintext
Key is some value used by the algorithm to encrypt plaintext

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13
Q

Symmetric Algorithms

A

Secret Key Algorithm (same key used to encrypt and decrypt a message
Weaknesses (Key Distribution, lacking nonrepudiation, not scalable (to lots of people)
Main Strength (Fast)

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14
Q

Asymmetric Algorithms

A

Public Key Algorithm (public and private key)
Sender encrypts the message with the receiver’s public key
Receiver decrypts the message with his own private key
Strengths (user maintenance and key management is easy, supports nonrepudiation, key distribution is simple)
Weakness (Slow)

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15
Q

Message Authentication

A

Hashing (mathmatical process that produces a digest of a message (similar to checksums); when the message changes, the digest changes as well; extremely unlikely for two messages to produce the same digest
Hashing allows the receiver to verify authenticity of the message
Digital signatures are used to verify the authenticity of a message

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16
Q

Cryptopraphic Algorithms

A 
Binary math used in most cryptographic algorithms (AND, OR, XOR) (most typically used XOR)
DES
Triple DES
IDEA-Blowfish-Skipjack
AES
RSA-El Gamal
Hashing Algorithms
Other Hashing Algorithms
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17
Q

DES

A

Symetrical Coding
Data Encryption Standard (DES)
Published in 1977
Adopted by US government as a standard for all data communications
64-bit block cipher
Key is 56-bit key (remaining 8 bits are parity bits)
4 DES modes
1-Electronic Codebook (ECB) (each 64-bit plaintext block is encrypted with the key)
2-Cipher Block Chaining (CBC) (the XOR operator is used to combine each plaintext block and the preceeding block before encryption)
3-Cipher Feedback (CFB) (the XOR operator is used to combine each plaintext block and the preceeding block after encryption)
4-Output Feedback (OFB) (similart to CFB, but the plaintext is combined with a seed value using the XOR operator

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18
Q

Triple DES

A 
Double DES (2DES)--No stronger than DES
Triple DES (3DES)
More secure implementation of the DES algorithm
Exists in three versions (all versions are equally secure)
Ecryption algorithm is the same as DES
E(K1,E(K2,E(K3,P))) 168 bits
E(K1,E(K2,E(K1,P))) 112 bits
E(K1,D(K2,E(K1,P))) 112 bits
E-encryption algorithm
D-decryption algormithm
K1, K2, K3-encryption keys
P-plaintext
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19
Q

IDEA

A

IDEA - International Data Encryption Algorithm (stronger alternative to DES)
Works on 64-bit blocks
Key starts at 128-bits
Key is broken into 52 16-bit subkeys
Subkeys are used to encrypt the plaintext
Very secure (used in commercial business)

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20
Q

Blowfish

A

Developed by Bruce Schneider as an alternative to DES and IDEA
Operates on 64-bit blocks
Key can vary from 32 bits to 448 bits

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21
Q

Skipjack

A

Block cipher operates on 64-bit blocks
Uses 80-bit key
Used in Clipper and Capstone high-speek encryption chips
Supports key escrow

22
Q

AES

A

Advanced Encryption Standard (AES) (Symetrical)
Based on Rijndael cipher
Allows three key strengths
128-bit key (requires 9 rounds of encryption)
192-bit key (requires 11 rounds of encryption)
256-bit key (requires 13 rounds of encryption)
Uses three transformation layers (Linear, nonlinear, key additional transform)

23
Q

RSA

A

Asymetrical have at least two key (public and private)
RSA created (1977) by (Ronald Rivest, Adi Shamire, and Leonard Adleman)
Most Popular
Depends on difficulty in factoring very large prime numbers

24
Q

El Gamal

A

1985 by Dr. T. El Gamal

Uses large integers and modular mathmetics to calculate keys

25
Q

Hashing Algorithms

A

a hash is taking a block of code and creating an output string of a block of code that represents a digest
SHA-1 (Secure Hash Algorithm)
developed by the National Institute of Standards and Technology (NIST)
Input any size
Always generates a 160-bit digest
MD2, MD4, and MD5 (Message Digest)
MD5 was developed by Ronald Rivest in 1991
Uses 4 computation rounds and produces a 12-bit digest

26
Other Hashing Algorithms
Haval (univeristy of Wallongong, Australia variable length output 128, 160, 192, 224, or 256 bits AND variable number of rounds 3, 4, or 5) RIPEMD-160 (European RACE Integrity Primitives Evaluation project with 160 bit output AND 5 paired rounds of 16 steps each)
27
Cryptographic Practices
``` Digital Signatures Signature Types Key Distribution Stenganography PKI ```
28
Digital Signatures
provides assurance that the message came from the stated sender AND did not change while in transit (Nonrepudiation and integrity)
29
Signature Types
Hashed Message Authentication Code (HMAC) (Uses shared secret keys, so it does NOT provide nonrepudiation BUT it is more efficient thatn public key encryption schemes Digital Signature Algorithm (DSA) (Asymmetric algorithm , Variable-length key size 512 and 1024 bits, works with SHA-1 digests Digital Signature Standard (DSS) (Documentation or standatd set forth by NIST that sets standards for all government cryptography usage, Standard states that DSA is used for digital signatures and SHA-1 for hashing)
30
Key Distribution
how distribute keys? Manual (paper or electronic) Public key encryption (once public key encryptions is set up, it can be used to exchange private keys) Diffie-Hellman Exchange (Algorithm used to calculate and exchange values on both sides; uses large integers and modular arithmetic; Each side produces the same large integer which is used as a secret key)
31
Stenganography
normal cryptography just encrypts a message Hides the fact that the message exists In normal use, the message is hidden inside another document graphics files are common carriers EX- every 16th bit could be changed without changing the actual image appearance
32
PKI (Public Key Infrustructure)
Ansymetric keys most common to use Digital certificate (a copy of a person's public key that is endorsed by a trusted third party) Certificate Authorities (CA) (neutral organizations that offer notarization services for digital certificates; the validity of the CA is the trust that users have in them) If a digital certificate is received from an unknown CA, do not accept it) Public keys are published as digital certificates CAs handles the generation and distribution of keys Trust in the CA provides assurance that the parties presenting the days are who they say they are
33
System Architecture
``` PEM MOSS S-MIME SSL HTTPS SET IPSec ISAKMP ```
34
PEM
Privacy Enhanced Mail (PEM) (secure e-mail standard that uses CA-managed digital certificates)
35
MOSS
MIME Object Security Services (MOSS) (suggested replacement for PEM that does NOT use CA digital certificates; provides associations between e-mail addresses and certificates; provides secure exchange of attached documents)
36
S-MIME
Secure/Multipurpose Internet Mail Extensions (S/MIME) (e-mail encryption standard; Uses X.509 digital certificates to exchange keys; routinely uses both symmetric and asymmetric algorithms; very configurable; very flexible
37
SSL
Secure Sockets Layer (SSL) (originally developed by Netscape to provide encrypted transfers between a Web client and a Web server; uses certificates; weakness as it provides encryption only to the web server which is usually outside the firewall; TLS should replace SSL)
38
HTTPS
Secure Hypertext Transfer Protocol (SHTTP/HTTPS) Differs from SSL in that each message is encrypted instead of creating a secure channel; supports 2-way authentication
39
SET
Secure Electronic Transactions (SET) by Visa and Mastercard
40
IPSec
IP Security (IPSec) (complete infrastructure for secure network communications; 1-Transport mode - only the payload is encrypted (can be used with VPM); 2-Tunnel mode - entire packet is encrypted, including the header (gateway to gateway connection through a VPN)
41
ISAKMP
Internet Security Association and Key Management Protocol (ISAKMP) (provides background services for IPSec; provides a method to maintain Security Associations of IPSec machines; provides key management)
42
Methods of Attack
``` Brute Force Known Plaintext Chosen Ciphertext Chosen Plaintext Meet-in-the-Middle Man-in-the-Middle Birthday Replay ```
43
Brute Force
Exhaustively attempts every possible combination to try to break a key Consumes substantial computing resources always look at the safety and security of algorithms as computing power changes
44
Known Plaintext
The attacker has a copy of the plaintext and ciphertext versions of the protected file; allows the attacker to analyze the relationship between the plaintext and the ciphertext
45
Chosed Ciphertext
If the attacker can decrypt portions of the encrypted message; the decrypted message fragment can be analyzed to possibly discover the key
46
Chosen Plaintext
attacker can encrypt palintext message; compare ciphertext with result of another encryption to possibly discover the key by matching the two
47
Meet-in-the-Middle
MIM attacker uses two simultaneous brute force attacks; works for algorithms that use two rounds of encryption; attacker encrypts a known plaintext with every possible key while decrypting the associated ciphertext with every possible key attack is successful when a match is found
48
Man-in-the-Middle
MIM (usual MIM) attacker sits betweeen an intended sender and receiver Intercepts session initiation and sets up a session from the sender to the attacker, and from the attacker to the receiver
49
Birthday
based on probability Also called the collision attack attempts to find a different message that produces the same digest If you have a room with at least 23 people there is a 50% chance that there are two people with the same birthday
50
Replay
Attacker intercepts a session and records it The session is played back later different from the MIM in that MIM is active not passive easily defeated by incorporating time stamps

CISSP Exam (32 decks)

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