Authentication - Being able to validate that a messages is from who it claims to be from. An intruder should not be able to masquerade as someone else.
Big Numbers - Very large numbers used in digital encryption and signatures. Big numbers those larger than 2^128 or 128 bits integer. For comparison the number of atoms in the planet(Earth) is 2^170 or 170 bits integer.
CA - Certifying Authority
Cert - Short for certificate
Certificate - A special format of a public key which has been signed by a Certifying Authority
Certifying Authority - A trusted entity that signs public keys
Digital Signature - A special hash or signature which is create using the private key and can only be validate using the matching public key.
Gabbi - Global Amateur Interchange format. This is the format that logbooks use to send tQSL data to LoTW servers.
Integrity - Being able to validate that the message hasn't been altered.
Message - Any message or data that is to be signed, such a QSL or public key
Nonredudiation - A sender should not be able to falsely deny later that he sent a message.
PKDS - Public Key Digital Signature.

PKI - Public Key Infrastructure. Because of the trust is require in using a PK system it requires a complex infrastructure which is called PKI.
Prime Numbers - Numbers that can only be divided by by itself and 1.
Principal - The person originating the message
Private key - A key which is used to sign messages which must be kept private
Public key - A key which can only be used to validate messages which has been signed with the matching private key.
Secret key - A key which is used in single key encryption systems. A private key should be stored encrypted with a secret key.

Because this digital signature and encryption protocols has many players standard names call dramatic personae have been given to them. Because we are only concern with digital signatures and certificates has been shorten to include only those we need.

### Dramatis Personae

Alice | First participant in all the all protocols
Bob | Second participant in the all protocols
Mallory | Malicious active attacker
Trent | Trusted arbitrator
Peggy | QSL service provider
Victor | Award sponsor verifier