A. In cryptography, encryption is the process of encoding a message or information in such a way that only authorized parties can access it and those who are not authorized cannot. Encryption does not itself prevent interference, but denies the intelligible content to a would-be interceptor. In an encryption scheme, the intended information or message, referred to as plaintext, is encrypted using an encryption algorithm – a cipher – generating ciphertext that can be read only if decrypted.  https://en.wikipedia.org/wiki/Encryption

A. Because TLS 1.3 changes the way keys are derived, it updates [RFC5705] as it also changes how Online Certificate Status Protocol (OCSP) messages are carried and therefore updates [RFC6066] and obsoletes [RFC6961]activities. Transport Layer Security (TLS) – and its predecessor, Secure Sockets Layer (SSL), which is now deprecated by the Internet Engineering Task Force  (IETF) – are cryptographic protocols that provide communications security over a computer network. Several versions of the protocols find widespread use in applications such as web browsing, email, instant messaging, and voice over IP (VoIP). Websites are able to use TLS to secure all communications between their servers and web browsers. https://en.wikipedia.org/wiki/Transport_Layer_Security

A. Random number generation is the generation of a sequence of numbers or symbols that cannot be reasonably predicted better than by a random chance, usually through a hardware random-number generator (RNG).

Random number generation https://en.wikipedia.org/wiki/Random_number_generation

Hardware random number generator  https://en.wikipedia.org/wiki/Hardware_random_number_generator

Quantum random properties. Because the outcome of quantum-mechanical events cannot in principle be predicted, they are the ‘gold standard’ for random number generation. Some quantum phenomena used for random number generation include: Photons travelling through a semi-transparent mirror. The mutually exclusive events (reflection/transmission) are detected and associated to ‘0’ or ‘1’ bit values respectively.

A. A digital certificate certifies the ownership of a public key by the named subject of the certificate, and indicates certain expected usages of that key. This allows others (relying parties) to rely upon signatures or on assertions made by the private key that corresponds to the certified public key.

One particularly common use for certificate authorities is to sign certificates used in HTTPS, the secure browsing protocol for the World Wide Web. Another common use is in issuing identity cards by national governments for use in electronically signing documents.

Extended Validation Certificate https://en.wikipedia.org/wiki/Extended_Validation_Certificate

Certificate authority https://en.wikipedia.org/wiki/Certificate_authority

A. the state or condition of being free from being observed or disturbed by other people.

Man-in-the-middle attack https://en.wikipedia.org/wiki/Man-in-the-middle_attack?data1=LiqRev

Privacy concerns with social networking services https://en.wikipedia.org/wiki/Privacy_concerns_with_social_networking_services