Hands on 6-3

In simple uniform hashing, each key is assumed to have equal probability to map to any of the hashes in a given table of size m. Given an open-address table of size 100 and 2 random keys, what is the probability that they hash to the same value? What is the probability that they hash to different values?   PLEASE give me a written paragraph answer

We have a poorly-designed hash map where all of the stored values are in one bucket (meaning they're all in one Linked List). Explain why this undermines the advantages of a hash map.

What is the big benefit of a digital signature over schemes like keyed hashes or incorporating a shared secret into a hash calculation? Select one: a. It solves the key exchange problem b. It prevents length extension attacks c. It saves having to calculate a digest d. It makes it difficult for the sender of a message to deny they sent it

Consider a CBHT (closed bucket hash table) in which the keys are student identifiers. Assume that the number of buckets m = 100 and hash function hash (id) = first two digits of id. #Starting with an empty hash table, show the effect of successively adding the following student identifiers: 000014, 990021, 990019, 970036, 000015, 970012, and 970023. Show the effect of deleting 000014 from the hash table.

For a n-bit hash function and m-bit messages, there are 2m-n (I,e; Two to the power m-n) messages per hash value. For example, m=1024 and n=128 there are 2 896 (two to the power 896) messages per hash value. Still. Why is it difficult to find hash collision?

The following is a list of binary keys:0011, 1100, 1111, 1010, 0010, 1011, 0111, 0000, 0001, 0100, 1000, 1001,0011.Design a hash function and an appropriate hash table to store and retrieve thekeys efficiently. Compare the performance when the set is stored as a sequential list.

Consider an extensible hash table that uses 4-bit hash keys and stores two records per bucket. Simulate the insertion, into an initially empty hash table, of records with (hash values of) keys 1111, 1110, 1101,..., 0001, 0000, in that order. Which combination of i (the number of bits used to index the bucket array) and a set of of keys belong to one bucket at some time during the sequence of insertions? Group of answer choices i​ ​=​ ​1;​ ​1110​ ​only. i​ ​=​ ​3;​ ​0101​ ​only.​ i​ ​=​ ​2;​ ​1111​ ​only.​ ​i​ ​=​ ​3;​ ​1000​ ​only.

This question relates to hash functions for block ciphers Block size = 4 bits Hash size = 4 bits Encryption function: Divide the key into two halves: LK and RK; Divide the plaintext into two halves: LT and RT; Then ciphertext= LC||RC where LC=LK XOR RT; and RC = RK XOR LT; where LC, RC, LT, and RT are each 2 bits; Plaintext and ciphertext are each 4 bits. g(H) = a 4-bit string that is equal to the complement of bits in H; For example, if H=A (Hexa) = 1010 (binary); then g(H)= 0101 H0 = Initial hash = C (in Hexa) Given message M:  D9 (in Hexa); a. Determine the hash (in hexadecimal) of the message M using Martyas-Meyer-Oseas hash function b. Determine the hash (in hexadecimal) of the message M using Davis-Meyer hash function c. Determine the hash (in hexadecimal) of the message M using Migayuchi-Preneel hash function

Consider an extensible hash table that uses 4-bit hash keys and stores two recordsper bucket. Simulate the insertion, into an initially empty hash table, of records with(hash values of) keys 1111, 1110, 1101,..., 0001, 0000, in that order. Simulate all 16insertions, indicating what happens after each insertion. Start with i=0 bit.

Problem 1 Suppose that we are using an extendable hash structure with buckets that can hold 3 records, and the hash function is h(x) = x mod 8. Using the final structure after the insertion of this sequence of values, 5, 7, 2, 3, 11, 17, 29, 31, 19, 23, 39, 14, which we discussed in class, please show the extendable hash structure after each of the following operations (each operation is applied to the result of the previous operation). After each deletion, attempt to recover space. (1) Delete 11 (2) Delete 31 (3) Insert 1 (4) Insert 15

Java program to implement a dynamically resizable hash table to store people’s names and Social Security numbers. Use the extraction method with division using the last four digits of the Social Security number. Use an initial table size of 31 and a load factor of 0.80. Use open addressing with double hashing using an extraction method on the first three digits of the Social Security number.

A hash file organization can have too many buckets. What are the reasons for this? What can be done to cut down on the number of bucket overflows?

If two different keys are hashed to the same location in a too-full hash table (A-1), what will be done by the Open Addressing technique? The table size is doubled (and rehashed) in order to accommodate the keys. Alternative cells are tried until an empty cell is found in the neighborhood. They are chained in two different linked lists at that location. They are chained in the same linked list at that location.

It's important to think about Lamport's OLP algorithm and its security in light of the features of the hash function.

1. Consider an open hash (that is, one that deals with collisions by using a linked list) with a million entries.  The hash algorithm takes 200ns to run, each comparison of objects takes 10ns, and everything else involved in the lookup takes trivial time.  How large does the hash table need to be to use less time on chained comparisons than on the initial hash lookup?  (Remember that you always have to compare once.)

Question 5 Assume you have a hash table of size 13, insert the following keys using open addressing with linear probing, assuming that the H(Key) = key % size and the bucket size is equal to 1.   Keys: 25, 66, 710, 150, 82, 111, 70,17           a. index key       0       1  66       2         3       4    82       5    70       6    17       7   150       8   710       9   111       10        11  25       12      b. index key       1       2  66       3         4       5    82       6    70       7    17       8   150       9     710       10   111       11        12       13  25     c. index key       0       1  66       2         3       4    82       5    70       6    17       7   150       8   111       9   710       10        11       12  25   d. index key       0       1  66       2         3       4    82       5    70       6    17       7   150       8   710       9   111       10        11       12  25

10. Consider a hash table that uses the linear probing technique with the following hash function f(x) = (5x+4)%11. (The hash table is of size 11). If we insert the values 3, 9, 2, 1, 14, 6, and 25 into the table, in that order, show where these values would end up in the table? Show all the calculations and actions that needs to perform for the values to be stored. index 0 1 2 3 4 5 8 9 10 value

Consider a linear hash table that uses 4-bit hash keys and stores two records per bucket. The capacity threshold is 75%; that is, we create a new bucket whenever the number of records is more than 3/2 the current number of buckets. Simulate the insertion, into an initially empty hash table, of records with (hash values of) keys 1111, 1110, 1101,..., 0001, 0000, in that order. Which of the following keys never appears alone in a bucket at any time during the insertion sequence? a) 1110 b) 1011 c) 0100 d) 1001

Consider a hash table of size M using separate chaining with ordered lists and the hash function hash(k) = k mod M.   a) Assume N items have already been inserted in the table. What is, in average, the cost (number of operations) needed for searching an item in the table? Justify your answer. b) Assume N items have already been inserted in the table. What is, in average, the cost (number of operations) needed for inserting the next (N+1)th item? Justify your answer.

We know that a digital signature is for the purpose of ensuring data integrity and authenticity. a) Checksum adds all the bits of the message (or blocks), is checksum a good way to construct a digital signature scheme? How about a hash function, i.e, Sign(M)= h(M)?b) If we use a hash to generate a signature in a more complicated way as follows Sign(k,m) = σ = h(k) XOR m XOR h(m), and m, σ will be sent along. Would this be a secure signature? Briefly explain. please do not use chegg or ai tool like chat gpt please

Five keys 8, 25, 10, 15, 18 have been added to a hash table of size 4 that uses Separate Chaining using hash function h(x) = x % 4. Show the resultant hash-table. %3D You have to insert two more keys 43 and 92 into the hash table. The designer of the hash table decided to resize the table by doubling its size when the load factor reaches or exceeds 1.5. Draw the new hash table after the insertions. The keys 2222, 1118, 1323, 2, 343, 2133, 155 and 95 are inserted into an initially empty hash table of length 10 using open addressing with hash function h(k) = k mod 10 with linear probing. What is the resultant hash table? %3D