the rail fence
Post on 01-Dec-2014
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DESCRIPTION
TRANSCRIPT
What is this line doing?
What are the two 26s for?
This is where we use the ApplyShifttoASCIICodeForCharacter functionTo get the encrypted text.
How do we decrypt?
The “rail fence”
T t a Jh i h r M oi s e m r ns y e s
Size = 4
The “rail fence”
T t a Jh i h r M oi s e m r ns y e s
Size = 4
The “rail fence”
T
h
i
s
i
s
t
h
e
a
r
m
y
M
r
J
o
n
e
s
Size = 4
The “rail fence”
T t a J
h i h r M o
i s e m r n
s y e
s
Size = 4
How the algorithm works
2 Counters
T t a Jh i h r M oi s e m r ns y e s
Counter one starts at the beginning and loops once only
Counter two starts at counter one and loops to the end
T t a Jh i h r M oi s e m r ns y e s
T t a J
h i h r M oi s e m r ns y e
s
For Count1 = 1 To SizeOfRailFence
While Count2 < OriginalText.Length Count2 = Count2 + SizeOfRailFence
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