2.7 This problem introduces a hash function similar in spirit to SHA that operates on lettersinstead of binary data. It is called the toy tetragraph hash (tth).8 Given a messageconsisting of a sequence of letters, tth produces a hash value consisting of four letters.First, tth divides the message into blocks of 16 letters, ignoring spaces, punctuation, andcapitalization. If the message length is not divisible by 16, it is padded out with nulls. Afour-number running total is maintained that starts out with the value (0, 0, 0, 0); this isinput to a function, known as a compression function, for processing the first block. Thecompression function consists of two rounds. Round 1: Get the next block of text andarrange it as a row-wise 4x4 block of text and convert it to numbers (A=0, B=1), forexample, for the block ABCDEFGHIJKLMNOP, we have81 thank William K. Mason and The American Cryptogram Association for providing this example.AB C D0 1 2 3EFG H46 758 9 10 11IJKLMNOP12 13 14 15Then, add each column mod 26 and add the result to the running total, mod 26. In thisexample, the running total is (24, 2, 6, 10). Round 2: Using the matrix from round 1, rotatethe first row left by 1, second row left by 2, third row left by 3, and reverse the order of thefourth row. In our example, BCD AG HEFLIJKPON M1 26 71115 14304 51013 128 9Now, add each column mod 26 and add the result to the running total. The new runningtotal is (5, 7, 9, 11). This running total is now the input into the first round of thecompression function for the next block of text. After the final block is processed, convertthe final running total to letters. For example, if the message is ABCDEFGHIJKLMNOP,then the hash is FHJL.a. Draw figures of the overall tth logic and the compression function logic.b. Calculate the hash function for the 48-letter message "I leave twenty million dollarsto my friendly cousin Bill."c. To demonstrate the weakness of tth, find a 48-letter block that produces the samehash as that just derived. Hint: Use lots of As.

the solution is an given below :

instead of binary data. It is called the toy tetragraph hash (tth).8 Given a message consisting of a sequence of letters, tth produces a hash value consisting of four letters. First, tth divides the message into blocks of 16 letters, ignoring spaces, punctuation, and capitalization. If the message length is not divisible by 16, it is padded out with nulls. A four-number running total is maintained that starts out with the value (0, 0, 0, 0); this is input to a function, known as a compression function, for processing the first block. The compression function consists of two rounds Pound 1: Get the next block of text and

instead of binary data. It is called the toy tetragraph hash (tth).8 Given a message consisting of a sequence of letters, tth produces a hash value consisting of four letters. First, tth divides the message into blocks of 16 letters, ignoring spaces, punctuation, and capitalization. If the message length is not divisible by 16, it is padded out with nulls. A four-number running total is maintained that starts out with the value (0, 0, 0, 0); this is input to a function, known as a compression function, for processing the first block. The compression function consists of two rounds Pound 1: Get the next block of text and

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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