Write a simple Scenario of Key Exchange with Encryption/Decryption between two parties Step 1: Key generation. Each person (or their computer) must generate a pair of keys that identifies them: a private key and a public key. Step 2: Key exchange... Step 3: Encryption. ... Step 4: Sending encrypted data.. Step 5: Decryption.

Write a simple Scenario of Key Exchange with Encryption/Decryption between two parties Step 1: Key generation. Each person (or their computer) must generate a pair of keys that identifies them: a private key and a public key. Step 2: Key exchange... Step 3: Encryption. ... Step 4: Sending encrypted data.. Step 5: Decryption.

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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The Caesar Cipher Algorithm was introduced in Week #1. Encryption is the act of encoding a message with the intent of allowing only authorized people the knowledge of how to read that message. An encrypted message can be decoded, allowing the secured content to be read after decryption. Recall that the Caesar Cipher uses alphabets as the primary source of information but shifted a certain number of letters to the left or right as a key to create the encrypted data. The Caesar Cipher is easily hacked because of the simple technique used to build the key that encrypts and decrypts the data. In this lab, the key is the number of alphabets shifted, and the direction is always toward the increasing alphabetical order. This provides 26 ways of encrypting a message and therefore makes it easier to be hacked by guessing the key within the range of 0 - 25. Write the function caesar_hack( ) that takes three parameters: a Caesar Cipher encrypted message, an alphabet list, and the original…
Consider a cryptosystem where the user enters a key in the form of a password. a. Assume a password consists of 10 characters , where each one is encoded using the ASCII scheme (7 bits per character). What is the size of the key space? b. What is the corresponding key length in bits? c. Assume that most users use 26 letters (lower and upper case) from the alphabet, what is the corresponding key length in bits in this case? d. At least how many characters are required for a password in order to generate a key length of 192 bits in case of letters consisting of(i). 7- bit characters?(ii). 26 lowercase letters from the alphabet?
IN JAVA PROGRAMMING LANGUAGE PLEASE , DO THE ENCRYPTION AND DECRYPTION FOR THIS CIPHER BUT USING THIS SOLUTION IN THE IMAGE AND NOT THE ONES ON THE INTERNET PLEASE I WANT THE RESULT OF ENCRYPTION TO BE THE SAME AS THE IMAGE AND FOR THE DECRYPTION TO GIVE THE SAME ORIGINAL MESSAGE
One of the problems with the Internet email system is that sending forged emails is relatively straightforward, i.e., it is easy to send an email with a fake sender/from address. One solution to this problem would be for a domain’s mail servers to digitally sign any email originating from the domain. For this to be useful, the public key would need to be made available to clients to validate the signatures. It is proposed that the public keys of the mail servers will be verified and signed by a certification authority (same as SSL/TLS certificates) and distributed via a standardised URL for the domain, e.g., https://mybusiness.com/email.pubkey. (a) Explain how the client would obtain the public key and validate the email server’s digital signatures. (b) Discuss the problem of trusting the obtained public key and how this solution results in public keys that can/cannot be trusted. (c) Indicate whether you believe this approach could be used to prevent forged emails and explain why it…
Affine Cipher is an example of a Monoalphabetic substitution cipher. The encryption process is substantially mathematical done by using the following formula: C = (P ∗ ?1 + ?2) mod 26. Where k1, k2 are two integers representing the key (selected randomly), C is the ciphertext value, and P is the plaintext value. Where C and P integers with values between 0 and 25. Write an Octave programme to implement this system, run your programme using the Plaintext: “the quick brown fox jumped over the lazy dog”. Show the obtained ciphertext with the selected values of the keys k1 & k2. Given that the plaintext “s” mapped to ciphertext “W”, plaintext “x” mapped to ciphertext “Z” when encrypted with Affine Cipher. Determine, mathematically, the values for the two keys K1 and K2.
suppose the RSA cryptosystem is used for sending secret messages with the private key (15,3) and the cipher text "4" is received. what is the plaintext?
An early attempt to force users to use less predictable passwords involved computer-supplied passwords. The passwords were eight characters long and were taken from the character set consisting of lowercase letters and digits. They were generated by a pseudorandom number generator with 215 possible starting values. Using the technology of the time, the time required to search through all character strings of length 8 from a 36-character alphabet was 112 years. Unfortunately, this is not a true reflection of the actual security of the system. Explain the problem.
Question # 06: The typical Computer Screen has a WIMP Setup. Most Common WIMP arrangements work on the basis of a Desktop metaphor, in which common actions are linked to similar actions in the real world. For Example, moving a File is achieved by selecting and dragging it into a relevant folder or filing Cabinet. Give Two Examples with explanation of the actions with their Real world Equivalents.
Consider a computer system with three users: Alice, Bob, and Cindy. Alice owns file X, and Bob and Cindy can read it. Bob owns file Y, and Cindy can read and write the file Y, but Alice can only read it. Cindy owns file Z, but neither Alice nor Bob can read or write it. If a user owns a file, he/she can also execute the file. Create the ACM (access control matrix) of the system Show the ACL and CL of the ACM Now Cindy allows Alice to read Z, Alice removes Bob's ability to read X, and Bob removes all the rights of Alice and Cindy to Y. Show the ACM after these changes.
A symmetric block encryption algorithm is shown below. 16-bit blocks of plaintext P are encrypted using a 32-bit key. Encryption is defined as: C = (P EX_OR Ko) + K1 C is the ciphertext, K is the secret key, Ko is the leftmost 16 bits of K, K1 is the rightmost 16 bits of K, EX_OR is bitwise exclusive OR, and + is binary addition. a. The ciphertext C must be the same size as the plaintext P, that is, it must not be larger than 16 bits. How can this be achieved? b. Show the decryption equation. How will the encrypted message be decrypted?
In cryptography, the Caesar cipher is a type of scroll cipher and is one of the simplest and best-known ciphers. When encrypting a message in the Caesar cipher, each letter is usually replaced by the letter three letters in the alphabet. Let the alphabetic scrollback look like this: aw w ww ww m ww w ww w vwwwwwww www ww wwm w w wwwm www ww defg hijkI mnop 9rstuvwxy z abc a bcd efghilj kI P9rstu v w xy z m Keep the encryption in the Python dictionary structure. www ww Write a Python program that takes the three-letter message as input and prints the encrypted message. Guidance: An empty string can be inserted one by one by replacing the letters of the input. wwwwwwwwwww www wn ww wn ww w www wwh m Entry: Message: kar Encrypted message: hxo Entry: Message: yel Encrypted message: vbi Entry: Message: ses Encrypted message: pbp Entry: Message: mtk Encrypted message: jqh
Write a Java program to encrypt and decrypt a phrase using two similar approaches, each insecure by modern standards. The first approach is called the Caesar Cipher, and is a simple "substitution cipher" where characters in a message are replaced by a substitute character. The second approach, due to Giovan Battista Bellaso (b 1505, d 1581), uses a key word, where each character in the word specifies the offset for the corresponding character in the message, with the key word wrapping around as needed.