What does "WPA" stand for?

Assume that passwords are selected from four-character combinations of 26 alphabeticcharacters. Assume that an adversary is able

tigry1 [53]

Answer:

for a) the time required is 228488.5 seconds= 63.469 hours

for b) the time required is 54 seconds

Explanation:

for a) since each combination is equally probable , then the number of possible combinations is

CT=Combinations = number of characters^length of password = 26⁴

then the number of combinations at time t will be the total , less the ones already tried:

Ct = CT - (n-1) , since n=α*t → Ct=CT-α*t

since each combination is equally probable , then the probability to succeed

pt = 1/Ct = 1/ (CT- α*t +1)

but the probability of having a success in time t , means also not succeeding in the previous trials , then

Pt = pt*П(1-pk), for k=1 to t-1

Pt = 1/ (CT- α*t +1) П[1-1/ (CT- α*k +1)] = 1/ (CT- α*t +1) П[(CT- α*k )] /(CT- α*k +1)]

since α=1 ,

Pt = 1/ (CT- t +1) П[(CT- k )] /(CT- k +1)] = 1/ (CT- t +1) * [CT- (t-1) ]/CT = 1/CT

then the expected value of the random variable t= time to discover the correct password is

E(t) = ∑ t* Pt = ∑ t *1/CT , for t=1 until t=CT/α =CT

E(t) = ∑ t *(1/CT) = (1/CT) ∑ t = (1/CT) * CT*(CT+1)/2 = (CT+1)/2

therefore

E(t) = (CT+1)/2 = (26⁴ +1)/2 = 228488.5 seconds = 63.469 hours

for b)

time required = time to find character 1 + time to find character 2 +time to find character 3 +time to find character 4 = 4*time to find character

since the time to find a character is the same case as before but with CT2=Combinations = 26 ,then

t= 4*tc

E(t) = 4*E(tc) = 4*(CT2+1)/2 = 4*(26+1)/2 = 54 seconds

6 0

4 years ago

How to find something in the cloud?

yanalaym [24]

Answer:

cloudsearch.google.com

Explanation:

This is where you will be able to hopefully find what your missing.

4 0

3 years ago

Write Java code that creates an array of n integers myArray, by taking n integers from the user with duplications, and do the fo

skad [1K]

Answer:

this should be what you need

Explanation:

import java.util.*;

public class ABC{

public static void main(String[] args) {

int n;

//create scanner object

Scanner sc = new Scanner(System.in);

//ask for size of array

System.out.print("Enter the size of array (n): ");

//read the input

n = sc.nextInt();

//create an array of n length

int [] myArray = new int[n];

//ask user for array elements

System.out.printf("Enter %d integers: ", n);

//read array elements

for(int i =0 ;i <5; i++)

myArray[i] = sc.nextInt();

//print the elements if myArray

System.out.print("1 - The values of myArray are: [");

for(int i =0 ; i < n; i++){

System.out.print(myArray[i]);

if(i < n-1)

System.out.print(", ");

}

System.out.print("]\n");

//calculate mean and sum of myArray elements

int sum = 0;

double mean = 0;

for(int i = 0; i < n; i++)

sum += myArray[i];

mean = (sum*1.0)/n;

//print the sum and mean of myArray

System.out.printf("2 - The sum is: %d. The mean is: %.1f\n", sum, mean);

//create an arraylist

ArrayList<Integer> myArrayList = new ArrayList<Integer>();

//copy the value of myArray to an arraylist without duplicates

for(int i = 0; i < n; i++){

if(!myArrayList.contains(myArray[i]))

myArrayList.add(myArray[i]);

}

sum = 0; mean = 0;

//display the values of myArrayList

System.out.print("3 - The values of myArrayList are: [");

for(int i =0 ; i < myArrayList.size(); i++){

System.out.print(myArrayList.get(i));

if(i < myArrayList.size()-1)

System.out.print(", ");

}

System.out.print("]\n");

//calculate sum and mean of myArrayList elements

for(int i = 0; i < myArrayList.size(); i++)

sum += myArrayList.get(i);

mean = (sum*1.0)/myArrayList.size();

//print the sum and mean of myArrayList

System.out.printf("4 - The sum is: %d. The mean is: %.2f\n", sum, mean);

}

3 0

3 years ago

Describe 6 difference of the types of computer<br>

Trava [24]

Answer:

<h3>1. Supercomputer</h3>

One of types of computers is supercomputer. It is a computer that is at the front-line of current processing capacity, particularly speed of calculation. It is usually used to do tasks involving intense numerical calculations such as weather forecasting, fluid dynamics, nuclear simulations, theoretical astrophysics, and complex scientific computations

<h3>2. Mainframe Computer</h3>

Another computer type is mainframe computer. It is a computer that is capable of handling and processing very large amounts of data quickly. Its calculation speed can reach millions to tens of millions instructions per second (MIPS) and it can respond to hundreds of millions of users at a time.

This computer type is mainly used in large institutions such as government, banks and large corporations.

<h3>3. Minicomputer (Mid-Range Computer)</h3>

Minicomputers are a class of multi-user computers that lie in the middle range of the computing spectrum, in between the smallest mainframe computers and the largest single-user systems (microcomputers or personal computers).

Minicomputers are usually small in scale, simple in structure, easy to maintain, and low in cost. Therefore, they are often used in universities, scientific research institutions and industrial control fields.

<h3>4. Microcomputer (Personal Computer)</h3>

The term “microcomputer” was introduced with the advent of systems based on single chip microprocessors. In the early days, the microcomputers would still have been too expensive to be owned by a single individual. But in the late 20th century, microcomputers became the most common type of computer.

Therefore, the term "microcomputer" has practically become an anachronism and has been replaced the term "personal computer (PC)".

Personal computer has developed rapidly because of its small size, convenient use, low production cost, and low price. PC computing speed can reach hundreds of thousands to millions instructions per second, which can meet the requirements of data processing and scientific computing in production, scientific research, and life.

<h3>5. Workstation Computer</h3>

A workstation computer is a high-end personal computer between microcomputers and minicomputers. It is usually equipped with large-capacity memory, external storage, and large-screen displays. Therefore, it has strong data processing capabilities and graphics processing capabilities.

Workstation computers are designed and developed mainly for professional application fields like engineering design, animation production, scientific research, software development, financial management, information services, analog simulation, etc.

<h3>6. Server Computer</h3>

A server refers to a high-performance computer that provides shared information resources and various services for many users on the network at the same time in a network environment.

A server is expected to be capable of high-speed computing, long-term reliable operation (it features error-correction of RAM; redundant cooling; self-monitoring, RAID), and powerful external data throughput.

The structure of the server is similar to that of an ordinary computer. Many smaller servers are actually personal computers that have been dedicated to provide services for other computers. But they are very different in terms of processing power, stability, reliability, security, scalability, and manageability.

According to the services provided, server computers can be subdivided into database server, file server, Web server, FTP server, etc.

<h2>hope helpful <3</h2>

4 0

3 years ago

How to paste picture in word without moving table.

gogolik [260]

You should Double Click then hit add

4 0

3 years ago