This document outlines types of cryptography based on key usage: symmetric, which relies on a single, shared key for both encryption and decryption, and asymmetric, which uses a public and a private key. It describes the principles of cryptographic techniques like substitution and transposition ciphers, emphasizing that encryption strength is influenced by key length. The text details the process of text encryption and the mathematical functions involved, ensuring user privacy against potential intrusions.

1. Cryptography
L02- Types Cryptography

2. outline
 types of Cryptography depending on the type of the key
● using Symmetric Key
● using Asymmetric Key
► The working principle of Cryptography texts
● substitution cipher
● Transposition cipher
► Strength encryption system
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3. types of Cryptography depending
on the type of the key
 using Symmetric Key
In this method is only dealing with the public key and the encryption
key and decryption themselves.
In the beginning is generated in an encryption key, which is a 128-bit or
256-bit or 64-bit is a bit stronger keys used with the 256-key.
The key 256-bit keys of the most complex because of the time needed
to know.
In the encryption process is used only in this public key to encrypt
information.
Decryption process certainly will be by the public key encryption that
has been done.
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4. Example Symmetric Key 4

5. types of Cryptography depending
on the type of the key
 using Asymmetric Key
In this way the two types are treated with the public key and private
key.
The public key encryption and be visible to everyone generates
private key Who will be a special public key.
In the decryption process must have the public key and the
algorithm used to generate the private key associated with the public
key.
Decryption process begins by generating private key, depending on
the algorithm and ends with the private key in the decryption process.
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6. Example Asymmetric Key 6

7. The working principle of
Cryptography texts
The texts used in the encryption process encryption algorithms work
and be a mathematical function used in encryption and decryption.
It works in combination with the key or password to encrypt read texts.
The process is generally understood to be the convert text using the
encryption algorithm to not understood text.
It offers the user full privacy in the lack of parasitism by the hacker,
though the intrusion will be a text not understood
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8. Example Cryptography texts 8
Hi man
$%FR@DVT
$#$O)%_+
(#IF
Hi manencryption decryption

9. The working principle of
Cryptography texts
 substitution cipher
In this process, each letter is replaced by the explicit text of the letter in
exchange for his.
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10. The working principle of
Cryptography texts
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 Transposition cipher
Based on the characters switch positions in one word

11. Strength encryption system
Is determined by the strength of encryption system based on the algorithm
used and the length of the user key, we mean key length
The number of bits that make up the key, and increase the safety factor
whenever the increase.
That the length of the first key factor in the strength of the encryption
system.
As we mentioned that there are a number of 64-bit lengths of 128 bits to
256 bits.
The length of the key that 256-bit keys stronger, as Each possibilities
number 2^256 to be able to detect key.
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12. Thanks for watching
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