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CISSP Exam Preparation
Cryptography
75
Computer Science
10/22/2009

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Cards

Term

RSA is a defacto used for

Definition

1- Encryption

2- Digital signatures

3- Key exchange

Term

What size is MD5 message digest (hash)

Definition

128 bit

Term

What does secure SHA-1 creates?

Definition

1- Fixed length message

2- Digest from a variable length input message

Term

what encryption do we use in PGP?

Definition

IDEA

Term

List IDEA's specifications

Definition

1- Symmetric

2- 64 bit block

3- 8 rounds

4- 128 bit key

5- Block cipher

6- Used in PGP

Term

Which is faster, IDEA or DES?

Definition

IDEA

Term
List Blowfish's specifications
Definition

1- Symmetric

2- Block cipher

3- 64 bit block

4- Key anywhere between 32 to 448

5- Goes through 16 rounds

Term

Which layer of OSI model provides non repudiation?

 

Definition

Application layer

Term
IS DES symmetric or Asymmetric?
Definition

Symmetric

Term
What is RSA  used for
Definition

1- Encryption

2- Digital signature

Term

Diffusion is carried out through...

Definition
Transportation
Term

Does RC4 provides hashing?

Definition
NO
Term

Which algorithm is vulnerable to man in the middle?

Definition
Diffie Hellman
Term
What is the maximum key size for RC5 algorithm?
Definition
2040 bits
Term
What are the two types of Cryptography algorithms?
Definition
Symmetric and Asymmetric
Term

List RC5 specifications

Definition

1- Created by Ron Rivest

2- Number of rounds up to 255

3- Symmetric

4- Block Cipher

5- Block size(s): 32,64 128

6- Keys goes up to 2048 bits

Term

List the "One time Pad" specifications

Definition

1- Made up of truly random values

2- Used only one time

3- Securly distributed to destination

4- secured at sender's and receive's site

5- At least as long as the message

Term
What is key clustering?
Definition

when two keys generate the same cipher text from the same plain text

Term
What is a "Key" ?
Definition

secret sequence of bits and instructions that governs the act of "Encryption" and "Decryption"

Term
Hint: The only secrecy is the key...
Definition
Keckhoff's principle?
Term
The estimate of the effort and resources it would take an attacker to penetrate a cryptosystem?
Definition
Work factor
Term
what is cryptosystem made up of?
Definition

1- Software

2- protocols

3- Algorithms

4- Key

Term
what do we call the study of cryptography  and cryptoanalysis?
Definition
Cryptology
Term
Rijndale replaced what algorithm?
Definition
3DES
Term
How many rounds does 3DES use?
Definition
48 rounds
Term
What is the mode that is used when encrypting individual characters are required?
Definition

Cipher Feed back mode

CFB

Term
What DES, what mode do we use for ATM and PINS?
Definition

ECB mode

Electronic Code Book mode

Term
Define DES
Definition
  1. Symmetric 
  2. Block cipher algorithm
  3. 64 bit key
  4. 56 make up the true key
Term
What do we call the practice of breaking cryptic systems?
Definition
Cryptanalysis
Term

what should we use for 1 secure communication?

Definition
Session key
Term
What algorithm uses Public and Private keys?
Definition

Asymmetric

 

which some times is referred to by

 

Public Key Cryptography

Term
Confusion is carried out through
Definition
Substitution
Term
What is Wasserar agreement?
Definition
Intangibles can be downloaded from the internet
Term
What cryptography algorithm provides "Authentication" and "non repudiation"?
Definition
Asymmetric
Term

What we call the DES mode that:

1- Functions like a stream

2- Cipher text is fed back to the algorithm to form a portion of the next input to encrypt the next stream of bit

Definition

Output Feed Back

OFB

Term
How do we calculate the number of symmetric keys needed ?
Definition
N(N-1)/2
Term
Is IDEA symmetric or Asymmetric?
Definition
Symmetric
Term
What is the formula of key Space?
Definition
2^8 = 256
Term
What are the two types of Ciphers?
Definition
Substitution and Transportaion
Term
What algorithm did Rijndael replaced?
Definition
3DES
Term
In which DES mode does each block of text, the key and the value, are based on previous block processed and applied to the next block?
Definition

CBC

Cipher Block Chaining

Term
Give an example about running key cipher?
Definition
Book number, page number, line number, etc..
Term
Give an example about Concealment cipher?
Definition
Message hidden within a message.
For example: Key- every 3rd word
Term
What is a keyspace?
Definition
All possible values that can be sed to generate a key
Term
When does Frequency analysis take place?
Definition
when patterns in Ciphertext are identified and matched back to plain text.
Term
what are the downfalls of symmetric algorithm ?
Definition
1- Key distribution
2- Scalability
3- Limited security
Term
Disadvantages of Asymmetric?
Definition
1- Very slow
2- Size of encrypted limited by key length
Term
If I encrypt data with my private key, who can decrypt it?
Definition
any one who has my public key.
Term
If I encrypt data with your private key, who can decrypt it?
Definition
That shouldn't happen. Private key should be known by you only.
Term
If I encrypt data with my public key, who can decrypt it?
Definition
Only me, because I have the private key
Term
If I encrypt data with my private key, what service does that provide?
Definition
Authentication
Term
why do we use asymmetric keys?
Definition
To encrypt symmetric keys
Term
What does Diffie-Hellman algorithm method allow?
Definition
It allows key agreement to happen in a secure manner.
Term
What algorithm replaces DES?
Definition
AES
Term
IDEA specs
Definition
1- Block Cipher
2- Operates on 64 blocks data
3- Key length 128-bits
4- Uses 8 rounds of 16 bit sub blocks
Term
Where can we use RC4 ?
Definition
SSL and WEP
Term
RC5 specs
Definition
1- Variable key size up to 2040
2- Block Cipher
3- Variable Block size 32,64,128
4- Variable rounds up to 255
Term
When does MAC take place?
Definition
When message and secret key are put together.
Term
what is MAC?
Definition
Message Authentication Code.
Term
List the algorithms that can be used for Digital Signatures..
Definition
DSA, RSA, El Gamal, ecc.
Term
DSA
Definition
Digital Signature Standard (DSS) — uses secure hash algorithm (SHA-1) and condenses message to 160 bits — Key size 512 to 1024
Term
If a symmetric key is encrypted with a receiver's public key, what security service is provided?
Definition
Confidentiality
Term
What is the difference between symmetric key and session key?
Definition
Session key can be used ONE TIME only
Term
What is DES?
Definition
It is symmetric block encryption algorithm.
It uses 64 bit key: 56 make up the true key, and eight bits are used for parity
DES goes through 16 rounds of transportation
Term
How many rounds does 3DES go through?
Definition
48 rounds.
It is Triple DES, means 3xDES
Term
How many keys does 3DES have? What are they?
Definition
It has three keys:
1- 128-goes through 10 rounds....192 bits-goes through 12 rounds.... and 256 bits-goes through 14 rounds
Term
What is Blow fish specs again?
Definition
64 Bit Block symmetric algorithm
It goes through 16 rounds
key ranges between 32 up to 448 bits
Term
Which Symmetric algorithm uses Stream Cipher?
Definition
RC4...
Term
A function that take a variable length and creates a fixed length value is called
Definition
One way hash
Term
The HAVAL algorithm creates what function?
Definition
Hashing
Term
The HAVAL algorithm, performs what function?
Definition
Hashing
Term
What does One-Way hash provides?
Definition
Integrity
Term
What does MD protect against?
Definition
Replay attacks
Term
What does PGP provides?
Definition
Confidentiality, Integrity, and Authenticity.
Term
What mail standard relied on Web trust?
Definition
PGP