Cryptography is the practice of securing communication through encryption and decryption techniques to transmit information secretly. There are three eras in the history of cryptography: the manual era, mechanical era, and modern era. The main types of cryptography are encryption, which locks up information, and decryption, which unlocks encrypted information. Cryptography uses keys, either symmetric keys where the same key encrypts and decrypts, or public key cryptography which uses two separate keys - a private key and public key.

1. CRYPTOGRAPHY
 By
 MEHAK IQBAL

2. Cryptography
Cryptography
come from Greek
words KRYPTOS “
hidden” +graphing’
“to write “
Is the practice and
study of
techniques for
secure
communicate in
the presences of 3
parties called
adversaries

3. History of cryptography
There are 3
eras of
cryptography
1.Manual era
.
2.Mechhanic
al era.
3.Modern era.

4. Type of Cryptography

5. Type of cryptography cont:
1.Encryption:
the process of locking up information using
cryptography . Information that has been locked up this way is
said to be encrypted .
2.Decryption:
The process of unlocked crypt information using cryptography.
Key:
The secret like a password like encrypt or decrypt
information .
There are few keys used in cryptography .
1.Secure line
2.Public line:

6. Type of cryptography cont:
1.Secure line:
A transmission channel which can be used to
send
information secretly like no body. Be intercept
or read
that data.
2.Public line:
A transmission channel which cannot be used
to send information secretly the information
can be overheard easily .
A public pay phone is an excellent example of
this so is the internet .
Type of cryptography cont

7. Type of cryptography cont:
3.Symmetric cipher :
the simpler types of cryptography, the
same key is used to encrypt and decrypt
information. This key is sometimes called
a symmetric key line
4.Public key cryptography:
In this of cryptography one key is used to
encrypt and a matching key is used to
decrypt

8.  These 2 key to gather are called a key
pair .
One of these keys is called the secret key
or
private key and should be kept secure.
The other is called the public key .

9. The end
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