Write pseudocode for the password guessing algorithm, Computer Network Security

Assignment Help:

Write Pseudocode for the password guessing algorithm:

Consider the following authentication protocol:

Client

Transmission

Host

Explanation

U, user

U à

 

I am user U

 

ß {n, DES, SHA-1}

n, random challenge, DES, SHA-1

- I have SHA_1(P(U)), where P(U) is password of user U

 

- Here is a random challenge n, please use DES and SHA-1 to generate a response

r=DES(n, SHA-1(P))

U, rà

 

Response r is the encryption of the hash of the password P of user U using key n, DES for encryption, and SHA-1 for hashing.

 

 

ß yes/no

Compare: DES-1(n, r) to SHA_1(P(U))

Can the password of user U be obtained by using an offline password guessing attack? If your answer is yes, describe the attack and write pseudocode for the password guessing algorithm.  If your answer is no, describe why the protocol is resistant to an offline guessing attack.

2) Using RSA, perform an encryption then a decryption of the message M=5 using p=3, q=11, and e=7. (please add explanation, Show all your work, not just the final answer.)

3) You are the designer of a password security policy that requires passwords to expire once they have a probability of 0.001 of being guessed.  A potential attacker can test 1,000,000 passwords per second. If you chose passwords to be alphanumeric ("A" through "Z", "a" through "z", and "0" through "9"), what would you have to set the maximum lifetime of a password to in order to meet the required guessing probability (represent in days)?Assume the password size is 9 characters.


Related Discussions:- Write pseudocode for the password guessing algorithm

Transmision imparment, What are Transmission Impairments? Explain the follo...

What are Transmission Impairments? Explain the following concepts with respect to Transmission Impairments a) Attenuation b) Delay Distortion c) Noise ion #Minimum 100 words ac

Explain how ethernet deals with collisions, (a) Describe how CSMA/CD operat...

(a) Describe how CSMA/CD operates and explain how Ethernet deals with collisions. (b) Describe how the subsequent protocols work: i. ARP ii. DHCP iii. DNS iv. SMTP (c) The

Describe how the encapsulated security header protocol, Question: (a) ...

Question: (a) Give 2 benefits of using IPsec. (b) IPSec uses two protocol for security: Authentication Header protocol (AH) and the Encapsulated Security Header Protocol (

Area subdivision, the advantages and disadvantages of area subdivision and ...

the advantages and disadvantages of area subdivision and where it is applicable

Netfilter firewall, Netfilter Firewall Netfilter is the popular name f...

Netfilter Firewall Netfilter is the popular name for the packet filtering system installed by default in the Linux kernel. The filtering system can be used as a very effective

Define full-duplex., A  full-duplex (FDX) , accepts communication in both...

A  full-duplex (FDX) , accepts communication in both ways, and, unlike half-duplex, accept this to occur simultaneously. Land-line telephone networks are full-duplex, since they

Research paper, how much would you charge for minimum 20 pages

how much would you charge for minimum 20 pages

Define repeater, Repeater known as regenerator ; it is an electronic mac...

Repeater known as regenerator ; it is an electronic machine that performs only at physical layer. It gets the signal in the network before it becomes loss or weak, recreates the

Ping command , In the early days when there were some dozen computers machi...

In the early days when there were some dozen computers machine on the network, it was done individually but now as we have looked that there are millions of computers on the intern

Define parity bit, PARITY BIT: A parity bit is an extra bit transmitt...

PARITY BIT: A parity bit is an extra bit transmitted with data item select to give the resulting bit odd or even parity. For example an even parity data packet 10100001 has p

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd