Cryptography

Description:

• Cryptography is the practice and study of techniques for securing communication and data in the presence of adversaries
• We say an encryption scheme is correct if decrypting a valid cipher-text should output the original plain text.
• topics:
  • digital signatures
  • Zero-knowledge proofs
  • public-key encryption
  • homomorphic encryption
  • threshold cryptography
  • pseudorandomness
• Adversary:
  • An actor who attemps to steal, hack, fake communication

Private key cryptography

Public-key cryptography

Hashing

Confusion and deffusion

• D
• Diffusion:
  • Making each plaintext bit affect as many ciphertext bits as possible
  • Permutation cipher
• Block ciphers built by iterationt
  • n as number of iteration