Given the following Diffie-Hellman scheme, which of the sentences below is/are correct? Select all that apply. Alice to Bob - "I'm Alice", [gª mod plalice Bob to Alice - g mod p {.) is encryption with specified PUBLIC key. [. is encryption with specified PRIVATE key. Trudy can exchange a key between herself and Alice Trudy can share gabmod p with both parties O Trudy can exchange a key between herself and Bob Trudy cannot share any key with the two parties

Given the following Diffie-Hellman scheme, which of the sentences below is/are correct? Select all that apply. Alice to Bob - "I'm Alice", [gª mod plalice Bob to Alice - g mod p {.) is encryption with specified PUBLIC key. [. is encryption with specified PRIVATE key. Trudy can exchange a key between herself and Alice Trudy can share gabmod p with both parties O Trudy can exchange a key between herself and Bob Trudy cannot share any key with the two parties

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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Can anyone please explain to me why we have such equations below in part b) and c)? They are the solutions to the questions, but I can't really understand why and how to get that. Many thanks. ==== QUESTION ==== In the Shamir secret sharing scheme, we distribute a secret among q different users as follows. If our secret is a message (m1, . . . , mk) from V (k, q) then, we encode it as a codeword of the Reed-Solomon RSk(q) and give one coordinate to each user. In this problem, we will use q = 7, k = 4 and the parity check matrix H4 below for RS4(7). H4 = [1 1 1 1 1 1 1, 0 1 2 3 4 5 6, 0 1 4 2 2 4 1] a) Write a generator matrix for RS4(7) b) A new secret is selected and user #1 receives share value 0, user #2 receives share value 6 and user #3 receives share value 1 and are collaborating to discover the new secret. Explain why they can’t recover the secret with only this information. c) Now, suppose users #1, #2 and #3 (as in the previous item) discover, in addition to the values of…
Hi! This is not a graded question I just need it for my reviewer. Thanks! 2.Recall that a public-key cryptosystem consists of three functions: A key generator G, an encryption function E, and a decryption function D. Any user, say Alice (A), can use the key generator to generate a key pair (PKA, SKA), in which PKA is Alice’s public key, and SKA is her secret key; she can then publish her name and public key in a directory. Subsequently, anyone who wants to send a private message x to Alice can look up PKA in the directory, compute a ciphertext y ←− E(x, PKA), and send y to Alice over an open line. Only Alice can compute x ←− D(y, SKA), because only she knows the decryption key SKA that corresponds to encryption key PKA. Note that there is no need for a key-distribution center, as there is when one is using a symmetric-key cryptosystem, but there is a need for public-key directories. a) What is a public-key certificate? What is the problem with public-key directories that certificates…
Write a program (Java, C) which the following 4 password breaking cases are implemented. The password file should contain 6-digit numbers only (from 000000 to 999999) and assume that the attacker knows that. MD5 pre-implemented open-source hash algorithm should be used. If applicable, For each case what Alice’s password is, what the salts are (if you use random text generator, you need to provide the range only). Test your program and make sure that you break the target passwords in every case. Add a wild guess for the time you break the target password(s) for every case. Case I: Trudy wants to determine Alice's password. Trudy does not use her dictionary 256/2 255 expected work Case II: Trudy wants to determine Alice's password. Trudy uses her dictionary If Alice's password is in the dictionary - 219 Else - 255 Total 1/4(219)+3/4 (255) ≈ 254.6 Case III: Trudy wants to determine any of the 1024 password in the file. Trudy does not use her dictionary If passwords were hashed…
Bob's public key is (55,3). Alice wants to send Bob the "message" 6. What is the cyphertext (encrypted version) of her message in the RSA cryptosystem? (Show the arithmetic, and you can use a calculator.)
a) Implement Playfair Cipher to get the ciphertext. Here, plaintext and key is given. Plaintext = "Fitness is the key", Key = "CRYPT".
A ciphertext has been generated with an affine cipher. The most frequent letter of the ciphertext is “F”, and the second most frequent letter of the ciphertext is “C”. Break this code by figuring out the key numbers. Hint: Based on the letter frequency, E is the most frequent letter and T is the second most frequent letter. Therefore, F should be the ciphertext of E and C should be the ciphertext of T.
8. Prior to the discovery of any specific public-key schemes, such as RSA, an existence proof was developed whose purpose was to demonstrate that public-key encryption is possible in theory. Consider the functions f₁(x₁) = Z₁; f₂(x2, y2) = Z2; f(x3, y3) = Z3 where all values are integers with Function can be represented by a vector M1 of length N, in which the kth entry is the value of Similarly, and can be represented by matrices M2 and M3. The intent is to represent the encryption/decryption process by table lookups for tables with very large values of N. Such tables would be impractically huge but could, in principle, be constructed. The scheme works as follows: Construct M1 with a random permutation of all integers between 1 and N; that is, each integer appears exactly once in M1. Construct M2 so that each row contains a random permutation of the first N integers. Finally, fill in M3 to satisfy the following condition: fi(fe(fi(k),p),k) = p for all k, p with 1 ≤k, p≤N In words, 1.…
Suppose Alice used a Hash function HA to encrypted her sensitive data. Everyone in the public can access her encrypted data. Group of answer choices She must keep HA secret and should not share it with others. She can share HA with other users. She must keep HA secret but can share it with others after encryption. None of the above.
Assume the cryptanalist has two pairs (x, y1) and (, y2) such that yl = DES(K, x) and y2 = DES(K,¤). Build a exhaustive key search which requires only 255 encryption to find out K. (This would be a slight improvement over the total number of 256 keys).
As discussed in Class 05, cryptography is the area of mathematics intended for the study of techniques and principles for transforming information from its original form to another, unintelligible form, so that it can be used only when authorized. According to the definition of encryption, carefully analyze the following situation presented below: For the transmission of encrypted messages between two points A and B, A generates a private key and forwards it to B, A encrypts the message using this same private key and sends this message to B, upon receiving the message, B decrypts the message with the same private key. Regarding the situation presented above, mark the alternative that corresponds to the encryption mode used. A) Cryptographic Abstract;B) Asymmetrical;C) Digital Certification;D) Symmetrical;E) Digital Signature.
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…
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…