Warning: foreach() argument must be of type array|object, bool given in /var/www/html/web/app/themes/studypress-core-theme/template-parts/header/mobile-offcanvas.php on line 20

Suppose that the cipher text, DVECFMV KF NFEUVI, REUYRK ZJKYV JVVUFW JTZVETV. was produced by encrypting a plain text message using a shift cipher. What is the original plain text.

Short Answer

Expert verified

MEN LOVE TO WONDER AND THAT IS THE SEED OF SCIENCE.

Step by step solution

Achieve better grades quicker with Premium

  • Unlimited AI interaction
  • Study offline
  • Say goodbye to ads
  • Export flashcards

Over 22 million students worldwide already upgrade their learning with Vaia!

01

Step 1

Given message:

DVECFMV KF NFEUVI, REUYRK ZJKYV JVVUFW JTZVETV

SHIFT CIPHER:

f(p)=(p+k)mod26

Corresponding cipher:

f-1(p)=(pk)mod26

The most common letter in the cipher text is E

Let

LetA=0,B=1,C=2,D=3,E=4,F=5,G=6,H=7,I=8,J=9,K=10,L=11,M=12,N=13,O=14,P=15,Q=16,R=17,S=18,T=19,U=20,V=21,W=22,X=23,Y=24,Z=25

V=21

The most common letter in the English text is V

Let

LetA=0,B=1,C=2,D=3,E=4,F=5,G=6,H=7,I=8,J=9,K=10,L=11,M=12,N=13,O=14,P=15,Q=16,R=17,S=18,T=19,U=20,V=21,W=22,X=23,Y=24,Z=25

E=4

The constant k is then the difference between the two numerical values of the two letters:

k="V" - "E" =214=17

02

Step 2

Given message:

DVECFMV KF NFEUVI, REUYRK ZJKYV JVVUFW JTZVETV

Let

LetA=0,B=1,C=2,D=3,E=4,F=5,G=6,H=7,I=8,J=9,K=10,L=11,M=12,N=13,O=14,P=15,Q=16,R=17,S=18,T=19,U=20,V=21,W=22,X=23,Y=24,Z=25

321425122110513542021817420102417102591024219212120522919252141921

Let us apply the decryption f-1(p)=(p17)mod26

124131114214191422141334170133197019818197418443145182841324

Let

LetA=0,B=1,C=2,D=3,E=4,F=5,G=6,H=7,I=8,J=9,K=10,L=11,M=12,N=13,O=14,P=15,Q=16,R=17,S=18,T=19,U=20,V=21,W=22,X=23,Y=24,Z=25

MEN LOVE TO WONDER AND THAT IS THE SEED OF SCIENCE.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free