Cryptography is the science of using mathematics to encrypt and decrypt data to enable secure storage and transmission of sensitive information. It involves using a key to convert plaintext into ciphertext that can only be read by the intended recipient. There are two main types: symmetric key cryptography which uses the same key for encryption and decryption and is faster, and asymmetric key cryptography which uses two different keys and is more secure but also more complex. Cryptography ensures confidentiality, authentication, integrity, access control and availability of data through techniques like substitution and transposition ciphers.

1. BLUE WHALE
RAZA HASSAN KALO 15TC49
SHEERAZ ALI MEMON 15TC57

2. CRYPTOGRAPHY
ENCRYPTION/DECRYPTION

3. Cryptography
Encryption/Decryption
Cryptography types
Encryption/Decryption Techniques
Block Cipher
OVER VIEW:

4. Cryptography:
 Cryptography is the science of using mathematics to encrypt and decrypt data.
 Cryptography enables you to store sensitive information or transmit it
across insecure network so that it can’t be read by anyone except the
intended recipient.

5.  VOCABULLARY
Plaintext:
Data that can be read and understood without any special measures.
Encryption:
The method of disguising plaintext in such a way as to hide it’s substance.
Decryption:
The process of reverting cipher text to its original plain text.
Cipher text:
The encrypted version of the message.
Key:
Some secret piece of information that customize how the cipher text is.

7.  Why Use:
 For “Secret Writing”
 To establish a shared secret when other people(eavesdroper)are listening.
Types:
Mainly classified into two types
1. Symmetric key cryptography
Same key is used by both parties.
Advantage: Simpler and Faster
Disadv: Less secured
2.Asymmetric key cryptography
Two different keys are used,user can get the key from certificate authority.
Advantage: More secured,Authentication
Disadv:Relatively Complex

10. Symmetric

11. Asymmetric

12. Traditional ciphers
 Substitution cipher
 Transposition ciphers
 Substitution cipher:
A technique in which letters/numbers/symbols of plain text are replaced by other
letters/numbers/symbols.
e.g: A-D , T-Z
2-5 , 3-6
 Transposition ciphers:
 In this position of letters/numbers/symbol are changed with one another.

13. • Plain text: Meet me after party
• Cipher text: Temeemefaptryrat
• Key used: 421635

14. Applications:
 Defence services
 Secure data manipulation
 E-commerce
 Internet payment systems
 Access control
 Data security

15. Conclusion:
By using of encryption techniques a fair unit of confidentiality,
authentication, integrity ,access control and availability of data is
maintained.
By using cryptography techniques ,will get secure your personal
data transmission as well as transaction and much more.