Cryptography is the art of securing messages through encryption to make them immune to attacks. It addresses issues of confidentiality, end-point authentication, message integrity, nonrepudiation, and entity authentication. Cryptography algorithms can be divided into symmetric key algorithms like DES and AES that use secret keys, and asymmetric key algorithms like RSA that use public keys. Famous cryptography algorithms and ciphers include DES, AES, and RSA, and they find applications in banking, commerce, records, networking, and government/military uses to keep secrets secret.

1. CRYPTOGRAPHY
• A word with Greek origins, means “secret writing”.
• art of transforming messages to secure and immune to attacks.
Cryptography Issues:
Confidentiality:
End-Point Authentication:
Message Integrity & Message
Nonrepudiation:
Entity Authentication:
Definition:
Keywords:
oPlaintext: original message and Ciphertext:
encrypted
oCipher: Encryption and Decryption algorithms

2. Cryptography Categories:
• We can divide all the cryptography algorithms (ciphers) into two
groups:
• Symmetric key (also called secret-key) cryptography
algorithms and
• Asymmetric key (also called public-key)
cryptography algorithms.
CRYPTOGRAPHY

3. Famous Algorithms/Ciphers And Applications:
• Modem symmetric-key ciphers: DES and AES
• RSA Algorithm: Rivest, Shamir, and Adleman of MIT
• Quantum Cryptography:
Keeping your Secrets secret!
● Used in the military and the government
● Now used in everyday life:
–Online banking, E-commerce
–Student records, health records, tax records etc.
–ATM machines
–Social networking (emails, texts, instant messengers), Businesses
CRYPTOGRAPHY
Uses of Cryptography: