Using a Caesar cipher.........................

Question

. Using a Caesar cipher decrypt the following message and determine the key used.
TPIEWI VIEH QI
Hint: Find the common letters

Answer 1

TPIEWI VIEH QI

 

I = 9, 9-4 = 5 = E

 

E = 5, 5-4 = 1 = A

 

T = 20, 20-4 = 16 = P

P = 16, 16-4 = 12 = L

I = 9, 9-4 = 5 = E

E = 5, 5-4 = 1 = A

W = 23, 23-4 = 19 = S

I = 9, 9-4 = 5 = E

 

 

V = 22, 22-4 = 18 = R

I = 9, 9-4 = 5 = E

E = 5, 5-4 = 1 = A

H = 8, 8-4 = 4 = D

 

 

Q = 15, 15-4 = 11 = K

I = 9, 9-4 = 5 = E

 

Shouldn't there be another letter added to the cipher? I.e.,

 

C = 3, 3-4 => 26+3-4 = 25 = Y

 

Then decrypted text is PLEASE READ KEY.