programming-for-dummies

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Symmetric/Asymmetric Encryption Algorithms
Plaintext I A M S A M .
Figure 5-3:
Cipherblock
chaining
uses the
output from
one block as
the input for
encrypting a
second
block.
Blocks
Ciphertext
I
A
Block cipher
encryption
X * 4
M S A M .
Altered cipher
encryption #1
d + 3
X * 4 d + 3 q Y ^
Altered cipher
encryption #2
q Y ^
Symmetric/Asymmetric Encryption Algorithms
The most common type of encryption algorithm is a symmetric algorithm,
which uses the same password to encrypt and decrypt data. Basically, this
means that the password that scrambles the data can also reverse the
process and unscramble the data, as shown in Figure 5-4.
Plaintext I A M S A M .
Key
Encryption
Ciphertext
X * 4 d + 3 q Y ^
Figure 5-4:
A single
password
can encrypt
and decrypt
a message.
Ciphertext
Plaintext
X * 4 d + 3 q Y ^
Key
Decryption
I A M S A M .