12 - Digital Signature Schemes

• Definition of a digital signature scheme as the triple (Gen, Sign, Verify).
• euf-cma experiment and security.
• hash-and-sign: definition and proof of security.
• RSA signatures:
  • Plain RSA:
    • no-message attack
    • targeted forgery
  • RSA-FDH:
    • definition
    • necessary conditions on H
    • proof of security in the random-oracle model
    • need for FDH to have large enough range
• Discrete-log signatures:
  • Identification schemes:
    • Definition
    • Non-degeneracy
    • Security
  • Fiat-Shamir transform:
    • definition
    • proof of security
  • Schnorr identification scheme:
    • definition
    • proof of security
  • * DSA and ECDSA
• * Signatures from Hash-functions:
  • Lamport's signature
  • Chain-based
  • Tree-based
• * Certificates and public-key infrastructures
• * SSL-TLS
• * Signcryption