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

Distinguish between steganograhy and cryptography, Question: (a) Disti...

Question: (a) Distinguish between Steganograhy and Cryptography. (b) "Playfair cipher is more secure than Monoalphabetic cipher." Justify this statement. (c) Various ap

Develop a completely secure wsn based on the triple key, Q. Develop a compl...

Q. Develop a completely secure WSN based on the triple key? Wireless network is the most vulnerable type of network to security attack. Unauthorized access to wireless network

Explain the approaches to lric modeling, (a) Cost allocation mechanisms ar...

(a) Cost allocation mechanisms are important when it comes to establishing other aspects of inter-firm compensations and how these are transferred to the users. There are two pri

Hybrid cryptography systems-cryptography, Hybrid Cryptography Systems Th...

Hybrid Cryptography Systems This makes use of different cryptography systems. Except digital certificates, pure asymmetric key encryption is not used extensively. Asymmetric enc

Draw a suitable physical network diagram, Question a) From the capture ...

Question a) From the capture below: Give the datagram source IP address, upper layer protocol, Total length in decimal and header checksum in hexadecimal; the segment source po

Describe the functioning of cloud computing, Question 1:  Describe the ...

Question 1:  Describe the functioning of cloud computing. Question 2: Discuss on "Platform as a Service". Question 3: Discuss the steps involved in effective co

TCP / IP, Let me know the details of protocol tcp/ip

Let me know the details of protocol tcp/ip

Address resolution with closed-form computation, ADDRESS RESOLUTION WITH CL...

ADDRESS RESOLUTION WITH CLOSED-FORM COMPUTATION For networks use reliable addressing, it is possible to select an address that creates closed-form address resolution possible.

Difference between flow control and congestion control, (a) Describe briefl...

(a) Describe briefly the difference between flow control and congestion control in relation to a connection-oriented protocol such as TCP. (b)  What is the initial rate of data

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