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

What is meant by certificate revocation, QUESTION (a) Which PKI (Public...

QUESTION (a) Which PKI (Public Key Infrastructure) model is typically favored by business organization? (b) Give one possible use of the "extensions" field of an X.509 certi

Malicious node detection mechanisms, Many applications are vulnerable to in...

Many applications are vulnerable to intrusion attacks and can provide misleading reports about misbehaving nodes. Some of the mechanisms under such a category include the Bayesian

Address resolution , Mapping between a hardware address and a protocol addr...

Mapping between a hardware address and a protocol address is known Address Resolution. A router or host uses address resolution when it requires to transmit a packet to another dev

Address resolution protocol (arp), ADDRESS RESOLUTION PROTOCOL (ARP) T...

ADDRESS RESOLUTION PROTOCOL (ARP) TCP/IP can use any of the three address resolution functions relaying on the addressing procedure used by the underlying hardware. To guarant

Define shift operation, SHIFT OPERATION:  This operation replaced all...

SHIFT OPERATION:  This operation replaced all bits to the left one position. For example in the diagram below a 16-bit CRC hardware is given, which needs three Exclusive OR (

Elliptic Curves, #questioAn elliptic curve y^2=x^3+ax+b(mod29) includes poi...

#questioAn elliptic curve y^2=x^3+ax+b(mod29) includes points P=(7, 15) and Q=(16, 13) a)Determine the equation of the crve b) Determine all values of x for which there is no point

Problem of spam mail, Topic -Spam is an ever-growing problem, with some net...

Topic -Spam is an ever-growing problem, with some network administrators reporting that 90% or moreof the email delivered to their mail servers is spam. Identify and briefly evalua

Legal, LEGAL, ETHICAL AND PROFESSIONAL ISSUES To minimize liabilities an...

LEGAL, ETHICAL AND PROFESSIONAL ISSUES To minimize liabilities and reduce risks, information security practitioner should: •    to understand current legal environment •    to s

Determine the round trip time, a) determine the RTT (round trip time) betwe...

a) determine the RTT (round trip time) between a client requesting a web page of 1024 bytes in size from an internal web server on a 100 Base-T Ethernet. Assume a one-way propagati

Gateways, Gateways They transfer packets among network machines that h...

Gateways They transfer packets among network machines that have different protocols (e.g. between a WAN and a LAN). They access a packet formatted for one protocol and change

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