Making TCP/IP Secure

Encryption

• A cipher is a general term for a way to encrypt data. like an algorithm which is underlies the cipher.
• Plain Text → Cipher Algorithm Using A Key → Encrypted CipherText

Substitution

Substitution is swapping letters of the alphabet for other letters of the alphabet.

• Caesar cipher

XOR

• Simple XOR: Simple XOR is just reversing the values. 0 + 1 = 1 and 1 + 1 = 0
• Use operation (a key): Just we use a key eight by eight.

Symmetric-Key Encryption

Encryption that uses the same key for both encryption and decryption.

• Block Ciphers
• Stream Cipher
• Weakness

Asymmetric-Key Cryptography

Encryption that uses different keys for encryption and decryption. Common algorithms : RSA, DSA, ECDSA.

• Motivation: To send a symmetric key to the decryptor without fear of interception.
• Steps

Encryption and the OSI Model