When you read A, it’s really a Z. When you read B, it’s really an A. This is a shift code. Every letter is shifted backwards by one letter. Look at the code and read the message at the bottom.

A-Z
B-A
C-B
D-C
E-D
F-E
G-F
H-G
I-H
J-I
K-J
L-K
M-L
N-M
O-N
P-O
Q-P
R-Q
S-R
T-S
U-T
V-U
W-V
X-W
Y-X
Z-Y

Now read this:

Hppe kpc!