Seminar 2
Symmetric
Encryption &
Message
C fid ti lit
Confidentiality
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Outline
•
Conventional Encryption Principles
•
Conventional Encryption Algorithms
•
Cipher Block Modes of Operation
•
Location of Encryption Devices
•
Key Distribution
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Simple ways to protect Message
Confidentiality
Example 2.1
Y
h
b
h
b
1
d dd hi
h f h
You choose a secret number, say the number 1, and add this to each of the
digit in the string “123456”:
123456
+
111111
↓
234567
Figure 2.1
A Simple Algorithm
Thus you will store the number “234567” instead.
To recover the original
number string, you just need to subtract the number “1” from each digit of
the stored number.
Others: (i) Use of translation and reverse translation tables
(transformations)
(ii) Permutations
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