Discrete Mathematics and Its Applications, Seventh Edition

Published by McGraw-Hill Education
ISBN 10: 0073383090
ISBN 13: 978-0-07338-309-5

Chapter 4 - Section 4.6 - Cryptography - Supplementary Exercises - Page 307: 2

Answer

a) $WXST TSPPYXI$ b) $NOJK KJGGPODJI$ c) $QHAR RABBYHCAJ$

Work Step by Step

(a) f(p) = (p+4) mod 26 Let us apply the function to 1819 1415 15 14 11 11 20 19 8 1413 22 23 18 19 1918 15 15 24 23 12 18 17 Let A=0, B=1, C=2, D=3, E=4, F=5, G=6, H=7, 1=8, J=9, K=10, L=11 M=12, N=13, 0=14, P=15, Q=16, R=17, S=18, T=19, U=20, V=21 W=22, X=23, Y=24, Z=25 WXST TSPPYXI (b) f(p) = (p + 21) mod 26 Let us apply the function to 18191415 15 14 11 11 20 19 8 14 13 13149 10 1096 6 15 14398 Let A=0, B=1, C=2, D=3, E=4, F=5, G=6, H=7, 1=8, J=9, K=10, L=11 M=12, N=13, 0=14, P=15, Q=16, R=17, S=18, T=19, U=20, V=21 W=22, X=23, Y=24, Z=25 (c) f(p) = (17p+ 22) mod 26 Let us apply the function to 1819 1415 15 14 11 11 20 19 8 1413 167017 17011247209 Let A=0, B=1, C=2, D=3, E=4, F=5, G=6, H=7, 1=8, J=9, K=10, L=11, M=12, N=13, 0=14, P=15, Q=16, R=17, S=18, T=19, U=20, V=21 W=22, X=23, Y=24, Z=25 QHAR RABBYHCAJ
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