<aside> 💡 Cryptography conceals data against unauthorized access.

</aside>

Problems Addressed by Encryption

Suppose a sender wants to send a message to a recipient.

• 메세지 전송 막음.
• 메세지를 가로챔.
• 메세지를 변경함.
• 실제 메세지로 위장한 메세지 만듦.

Encryption Terminology

• Sender

• Recipient

• Transmission medium

• Interceptor/Intruder

• Encrypt, encode, or encipher

• Decrypt, decode, or decipher

• Cryptosystem

  → A system for encryption & decryption

• Plaintext

  → 메세지 원본

• Ciphertext

  → 암호화된 메세지