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

Access control list, Scenario: A network with individual hosts (really, vir...

Scenario: A network with individual hosts (really, virtual machines) can run HTTP (web) servers that are available to the outside. (Here, available means the ability to read and wr

Cracking the Vigenere Cipher, The following message was enciphered with a V...

The following message was enciphered with a Vigenère cipher. aikiaawgfspxeppvjabjnivulfznzvkrlidamsmyamlvskniyffdpbwtnxsvvbtnamvltsefoeycztkomylmerkwrs deusjgecmzkwvnreeyp

Explain the schemes for distribution of public keys, (a) What is a pseudora...

(a) What is a pseudorandom generator? Give an example describing how it works. (b) Explain the key components of a wireless network and their purpose. (c) Describe the authen

Distinguish between a mobile agent state and code, Question: (a) Disti...

Question: (a) Distinguish between a mobile agent "state" and "code". (b) Differentiate between "weak" and "strong" mobility. (c) Mobile agent systems are known to have

Compare and contrast between block and stream ciphers, Problem 1 Solve ...

Problem 1 Solve the following Caesar cipher by showing your working: EM KIUM EM AIE EM KWVYCMZML Problem 2 Compare and contrast between block and stream ciphers, listin

Characteristics of radial basis function neural networks, Problem : (a)...

Problem : (a) Provide one possible classification of PCA, ART, RBF, and Fuzzy ARTMAP networks. (b) Describe in detail the characteristics of Radial Basis Function Neural Net

Wireless local area network, a) Wireless local area network (WLAN) technol...

a) Wireless local area network (WLAN) technologies constitute a fast-growing market introducing the flexibility of wireless access into office, home, or production environments. G

Algorithm, algorithm on simple intrest

algorithm on simple intrest

Arp responses, ARP RESPONSES Let's search out how does a computer know...

ARP RESPONSES Let's search out how does a computer know whether an incoming frame have an ARP message. The type field in the frame header defines that the frame contain an ARP

Define multimedia and application of multimedia, Describe the salient featu...

Describe the salient features of the multimedia. Also explain the applications of it. Multimedia can be understood as follows: Multimedia is on the whole a media which makes

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