Trapdoor one-way functions. RSA, Diffie-Hellman, ElGamal, and elliptic curve cryptosystems. Hash functions and message-digest functions. Sharing and partial disclosure of secrets. Zero-knowledge proof systems.
Key management architectures.
Escrowed encryption systems. Key recovery methods. Practical systems, e.g., Kerberos and Pretty Good Privacy. Textbook W. Stallings . Prentice Hall, 1998.