3. A computer system uses passwords that contain exactly eight characters, and each character is one...
A computer system uses passwords that contain exactly 3 characters, and each character is one of the 26 lowercase letters (a-z) or 26 uppercase letters (A-Z) or 10 integers (0-9). Let Ω denote the set of all possible passwords, and let and denote the events that consist of passwords with only letters or only integers, respectively Suppose that all passwords in 2 are equally likely. Determine the following probabilities. Round your answers to three decimal places (e.g. 98.765). (c) The...
A computer system uses passwords that contain exactly 4 characters, and each character is 1 of the 3 lowercase letters (a, b, c) or 3 upper case letters (A, B, C) or the 5 odd digits (1, 3, 5, 7, 9). Let Ω denote the set of all possible passwords, and let A and B denote the events that consist of passwords with only letters or only integers, respectively. Determine the probability that a password contains only numbers given that...
A computer system uses passwords that contain exactly 3 characters, and each character is 1 of the 3 lowercase letters (a, b, c) or 3 upper case letters (A, B, C) or the 5 odd digits (1, 3, 5, 7, 9). Let Ω denote the set of all possible passwords, and let A and B denote the events that consist of passwords with only letters or only integers, respectively. Determine the number of passwords for Ω. Report the exact number
A company‘s computer system requires passwords to be 7 to 9 characters long, and to consist of uppercase and lowercase letters {A, a, B, b, C, c, . . . , Z, z}, digits {0, 1, 2, 3, . . . , 9} and the special characters {&, #, $, *, +, _}, and to contain at least one special character or digit. How many such passwords are there?
A hacker has programmed their computer to generate, uniformly at random, an eight-character password, with each character being either one of 26 lower-case letters (a-z), one of 26 upper-case letters (A-Z) or one of 10 integers (0-9). The hacker wants to infiltrate a website that has 2 million users. Assume, for simplicity, that each user is required to use a unique password. i. What is the expected number of attempts before the hacker successfully generates a user password? ii. What...
Question 3: a. A computer password is 6 characters long. A character can be either a digit or an uppercase English letter. A valid password must contain exactly one digit. How many valid passwords are there? (hint: you do not know the position of this one digit. It might be in the beginning or the end or the middle of the password. You may use the combination low to select the position of this digit and then assigno value to...
Problem 1. Assume a password in a computer system contains eight character, each can be a digit (0 to 9), an uppercase English alphabet, or a lowercase English alphabet. How many password are there (a) if letters can be repeated? (b) if no letter can be repeated? (c) starts with X and letters can be repeated? (d) either starts with X or ends with 10 (letters can be repeated)? (e) neither starts with X nor ends with 10 (letters can...
4: A certain computer program is accessed by entering a user-defined password. If the password a. can contain any lowercase letter, uppercase letter, or digit from 0-9, and must contain 10 characters, how many possible passwords are there if no character can be used more than once? Express your answer as a factorial statement. Is 8 an example of permutations or combinations? b. 4: A certain computer program is accessed by entering a user-defined password. If the password a. can...
Compute the number of passwords of each type below along with how long it would taketo test all possible such passwords if it takes 1 nanosecond to test a password. Report the times in the most convenient human understandable form. In all of these, unless noted otherwise, order matters and repetition of characters is allowed. Passwords of length 8 with any combination of lowercase letters, uppercase letters,and numbers. Passwords that start with a capital letter, have 10 lowercase letters, and...
Cryptology 1.4. We now consider the relation between passwords and key size. For this purpose we consider a cryptosystem where the user enters a key in the form of a password. 1. Assume a password consisting of 8 letters, where each letter is encoded by the ASCII scheme (7 bits per character, i.e., 128 possible characters). What is the size of the key space which can be constructed by such passwords? 2. What is the corresponding key length in bits?...