q7- Please answer question in yellow highlight, All the other info in the attachment is for context Q7. Consider the diagram below and answer the following questions relating to blockciphers:KeyInitialization Vector (IV)▬▬▬▬▬▬▬▬▬-block cipherencryptionPlaintext‒‒‒‒‒‒‒▬▬▬▬▬▬▬Key →→→CSE2SIA 2022 Sample ExamPlaintextblock cipherencryptionCiphertextCiphertextWhat block cipher mode of operation is shown? [Block cipher mode of OperationKey →Plaintextblock cipherencryptionBlock cipher is a method of encryption which uses a fixed length input and the output will be thesame length cipher text. There are several mode of operations in a Block cipher mode.In the above figure it representing the Output Feedback Mode (OFB).In output feedback mode by using initialization vector and key an encrypted output is createdand this is send to the next encryption block as feedback. And this encrypted output and plaintextare XORed together to get the original ciphertext in the current block. That is the original cipher inthe current block is not sending to the next block.▬▬▬▬▬▬▬▬▬CiphertextIt helps to reduce bit transmission errors. And in OFB mode dependency between plain textand cipher text is very less.Here in the figure the Encryption operation using OFB mode is described.Which operation (encryption/decryption) is described in the diagram?modePage 4The changes needed in the diagram to make it Decryption operation using OFBThe given figure is representing Encryption operation using OFB mode. The changes needed in thediagram to make it Decryption operation using OFB mode is in the figure the encrypted outputand plain text is XORed instead of that in decryption the cipher text and encrypted output isXORed in the decryptionDescribe the change required in the diagram to perform the reverse operation(encryption decryption)Using this block cipher mode, which of the operations is faster (if any)? Brieflyexplain why this is so

1. The encryption process utilizing the OFB mode is depicted in the following image. To convert the…

Describe the change required in the diagram to perform the reverse operation (encryption decryption) Using this block cipher mode, which of the operations is faster (if any)? Briefly explain why this is so

Describe the change required in the diagram to perform the reverse operation (encryption decryption) Using this block cipher mode, which of the operations is faster (if any)? Briefly explain why this is so

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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Question 2 Please implement a statistical attack for Caesar Cipher by computing Correlation: ?(?)|?=[0,25] based on slides L7 pages 16-19. Use your implemented attack to infer the key and the plaintext for the following cipher texts a. XTKYBFWJXJHZWNYD b. KCECMKS Full explain this question and text typing work only thanks
should a hash function be reversible? - no, because this woild allow the plaintext to be decrypted from the hash, rendering message digests and digital signatures unworkable -yes, because this would allow the hash to contribute to error detection and correction operations -in a limited way, they are reversible, bevause the hash acts as a pointer or key into database and file management systems where the plaintext comes from -none of the above
Hence, organizations with established IAM practices can rapidly adopt cloud services while maintaining the efficiency and efficacy of their security controls.We are aware that a digital signature serves to guarantee the validity and purity of data. a) Since checksums add up all the message's bits (or blocks), are they a viable method to build digital signature schemes? Consider a hash function, such as Sign(M)=h(M).b) If we create a signature using a hash in a trickier manner, as in Sign(k,m) = = h(k) XOR m XOR h(m), then m, will be transmitted. Would this warning be trustworthy? Describe in detail. Please refrain from using chegg or other AI tools like chat GPT.
1- Consider password authentication :(a) Suppose an off-line dictionary attack is used, and suppose the attacker has prepared a dictionaryof 10,0000 entries, the password file contains 1000 users with 50 different salt values(Salt valuescorrelation to user accounts attackers is unknown to the attacker). If the attacker’s goal is to get asmany passwords as possible, how many hash values would the attacker compute in the worst case?(b) Based on the above part, how many comparisons between hash values are needed in the worse case? 2- A Digital Certificate usually contains an identity and other fields such as certificate issuer’sname .. etc :(a) Explain the process for a service owner (i.e. web application) to get a Digital Certificate ?(b) How does the Digital Certificate issued in part(a) enable any end user to detect the man in themiddle attack?(c) What is the impact on the validity of the Digital Certificate if the hash algorithm used is not weakcollision resistant? Justify your answer…
A cipher suite is a choice of algorithms for key exchange, authentication and encryption to be used together in TLS. Cipher suites are specified by an abbreviation such as the following: “ADH-DES-CBC-SHA”. Search online and find one example of a cipher suite used in TLS 1.3. Write the name of the cipher suite; then, for each component, write what the abbreviation stands for and for which cryptographic task that algorithm is used in that suite.
5) Please disclose all the differences between Hash function and Message Authentication Code (MAC)
Consider the following threats to Web security and describe how each is countered by a particular feature of TLS. A. Brute-Force Cryptanalytic Attack: An exhaustive search of the key space for a conventional encryption algorithm. B. Known Plaintext Dictionary Attack: Many messages will contain predictable plaintext, such as the HTTP GET command. An attacker constructs a dictionary containing every possible encryption of the known-plaintext message. When an encrypted message is intercepted, the attacker takes the portion containing the encrypted known-plaintext and looks up the ciphertext in the dictionary. The ciphertext should match against an entry that was encrypted with the same secret key. If there are several matches, each of these can be tried against the full ciphertext to determine the right one. This attack is especially effective against small key sizes (e.g., 40-bit keys). C. Replay Attack: Earlier TLS handshake messages are replayed. D. Man-in-the-Middle Attack: An…
Bob has uploaded a very large file in his online file storage. Later, he needs to download the file and verify whether the file has been modified. A. If a cryptographic hash function can be applied, briefly describe how to use a hash function to file integrity checking? B. Why doesn't Bob save the whole big file locally and directly compare it to the file he downloads?
Provide a solution to the issue outlined below by identifying the security weaknesses in each of the authentication methods.When Bob hashes a password, he compares it to a list of previously hashed passwords in a database.Bob performs a hashing technique on a password and then compares it to a database of hashed passwords.
Please do both questions. Thank you in advance. Subject- Security Governance Type 1: Calculation of hash values for given keys –In this type of questions, hash values are computed by applying given hash function on given keys. Que – 1. Given the following input (4322, 1334, 1471, 9679, 1989, 6171, 6173, 4199) and the hash function x mod 10, which of the following statements are true? i. 9679, 1989, 4199 hash to the same valueii. 1471, 6171 has to the same valueiii. All elements hash to the same valueiv. Each element hashes to a different value(A) i only(B) ii only(C) i and ii only(D) iii or iv Type 2: Insertion of keys into hash table using linear probing as collision resolution technique –In linear probing technique, collision is resolved by searching linearly in the hash table until an empty location is found. Que – 2. The keys 12, 18, 13, 2, 3, 23, 5 and 15 are inserted into an initially empty hash table of length 10 using open addressing with hash function h(k) = k mod 10 and…
Find the holes in the following authentication methods and provide a fix to the identified issue:In order to verify the authenticity of a password, Bob first generates a hash of it and then compares it to a collection of previously hashed passwords.Bob uses a hashing technique to run a password twice and then compares the results to a database of hashed passwords.
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