Scratch Book

Message => Hash => Message digest

Message => Key => Secret => Key => Message

Message => Public key => Secret => Private Key => Message

Message => Private key => signature => Public Key => Validation

Message => Hash => Message digest => Private key => signature => Public Key => Message digest

Public key => Verisign Private key => Certificate => Verisign Public Key => Public Key

Challenge key+Password => Hash => digest => Public Key => Challenge response => Private key => digest