Answer to Question #259775 in Discrete Mathematics for rtf

Question #259775

Decrypt the word “xqjjud” mathematically with a shift of 5

Expert's answer

To make all of this more mathematical, consider the following conversion table for the English alphabet:

"\\def\\arraystretch{1.5}\n \\begin{array}{c}\n 0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \\\\ \n A & B & C & D & E & F & G & H & I \\\\\n \\\\\n 9 & 10 & 11 & 12 & 13 & 14 & 15 & 16 & 17 \\\\ \n J & K & L & M & N & O & P & Q & R \\\\\n \\\\\n 18 & 19 & 20 & 21 & 22 & 23 & 24 & 25 \\\\ \n S & T & U & V & W & X & Y & Z \\\\\n\\end{array}"

i. Using the table, we can represent the letters in our message “xqjjud” with their corresponding numbers: "23 \\ \\ 16 \\ \\ 9\\ \\ 9\\ \\ 20\\ \\ 3."

ii. Now subtract 5 (the encryption key) to each number to get: "18 \\ \\ 11 \\ \\ 4\\ \\ 4\\ \\ 15\\ \\ 24."

iii. Now use the table to replace these numbers with their corresponding letters: "sleepy"