Encrypt the Plaintext Below Using the Caesar Cipher

Only available on StudyMode
  • Download(s) : 51
  • Published : December 14, 2010
Open Document
Text Preview
 
 

Exercise
 1:
 
 
Encrypt the plaintext below using the Caesar cipher: THE CAESAR CIPHER IS A TYPICAL EXAMPLE OF A SUBSTITUTION CRYPTOSYSTEM.

 
 
 
 
 
 
 
  t
  19
  22
  w
 

a 0 n 13

b 1 o 14

c 2 p 15

d 3 q 16

e 4 r 17

f 5 s 18

g 6 t 19

h 7 u 20

i 8 v 21

j 9 w 22

k 10 x 23

l 11 y 24

m 12 z 25

Encryption
 formula:
 f(x)= x+k (mod26) Character to be shifted to the right by k; x is the characterʼs numerical equivalent.   h
  7
  10
  k
  e
  4
  7
  h
  c
  2
  5
  f
  u
  20
  23
  x
  a
  0
  3
  d
  b
  1
  4
  e
  e
  4
  7
  h
  s
  18
  21
  v
  s
  18
  21
  v
  t
  19
  22
  w
  a
  0
  3
  d
  r
  17
  20
  u
  c
  2
  5
  f
  i
  8
  11
  l
  u
  20
  23
  x
  p
  15
  18
  s
  t
  19
  22
  w
  h
  7
  10
  k
  i
  8
  11
  l
  e
  4
  7
  h
  o
  14
  17
  r
  r
  17
  20
  u
  n
  13
  16
  q
  i
  8
  11
  l
  c
  2
  5
  f
  s
  18
  21
  v
  r
  17
  20
  u
  a
  0
  3
  d
  y
  24
  1
  b
  t
  19
  22
  w
  p
  15
  18
  s
  y
  24
  1
  b
  t
  19
  22
  w
  p
  15
  18
  s
  o
  14
  17
  r
  i
  8
  11
  l
  s
  18
  21
  v
  c
  2
  5
  f
  y
  24
  1
  b
  a
  0
  3
  d
  l
  11
  14
  o
  e
  4
  7
  h
  x
  23
  0
  a
  e
  4
  7
  h
  a
  0
  3
  d
  m
  12
  15
  p
  p
  15
  18
  s
  l
  11
  14
  o
  e
  4
  7
  h
  o
  14
  17
  r
  f
  5
  8
  i
  a
  0
  3
  d
 

s
  18
  21
  v
 
 
 
 

i
  8
  11
  l
 

t
  19
  22
  w
 

s
  18
  21
  v
 

t
  19
  22
  w
 

m
  12
  15
  p
 

WKHFDHVDUFLSKHULVDWBSLFDOHADPSOHRIDVXEVWLWXWLRQFUBSWRVBVWHP  
 
 
 
 
 Ciphertext:
 WKH
 FDHVDU
 FLSKHU
 LV
 D
 WBSLFDO
 HADPSOH
 RI
 D
 VXEVWLWXWLRQ
 FUBSWRVBVWHP
 
 

 

1
 


 
 

Exercise
 2
  1) How would you test a piece of cipertext to determine quickly if it was the likely results of a transposition? If we know the key (shift), the formula f(x)=x-k (mod26) can be used ; x being the encrypted value.

w
  22
  19
  t
  v
  21
  18
  s
 

k
  10
  7
  h
tracking img