Cryptography Foundations and TLS Lecture

These flashcards cover the fundamental concepts of cryptography discussed in the lecture, including cryptographic primitives, symmetric and asymmetric encryption, hashing, and the TLS protocol.

Cryptographic primitives

The low-level building blocks, such as encryption and hashes, that are used as high-level assembly units for defenders to build protocols.

Symmetric encryption

A fast form of cryptography where a single shared secret key is used for both encrypting and decrypting data.

Hash function

An operation that takes an arbitrary piece of data and produces a fixed-length output, acting as a unique fingerprint for that data.

Digest

The output produced by a hash function; small changes in the original message result in a completely different output.

MAC (Message Authentication Code)

A cryptographic tool that provides a guarantee that a message was created by someone sharing the same secret key, ensuring integrity and authentication.

AEAD (Authenticated Encryption with Associated Data)

A packaged solution used in protocols like TLS that combines symmetric encryption and MACs into one bundle to reduce configuration mistakes.

Nonce

A non-private piece of extra data sent alongside an encrypted message to ensure the output varies even when the same data is encrypted multiple times.

Public key cryptography

A system involving a public key for encryption and a related private key for decryption, eliminating the need for a pre-shared secret.

Diffie-Hellman key exchange

A method where two parties independently derive the same shared secret key using their own private keys and the other party's public key.

Digital signature

A code created by signing the hash of a message with a private key, allowing others to verify the authenticity of the sender using a public key.

TLS (Transport Layer Security)

The standard protocol used for secure web browsing that provides confidentiality, integrity, and authentication by negotiating cryptographic primitives.

Forward secrecy

A security property achieved by rotating session keys so that if a current key is stolen, it cannot be used to decrypt past messages.

Certificate Authorities

Centralized entities in a top-down trust system responsible for vetting organizations and signing their digital certificates.

Rainbow tables

Large tables of pre-computed passwords and their corresponding hashes used by attackers to look up unsalted passwords.

Salt

Data added to the hashing process of passwords to ensure that even identical passwords result in different hashes, making rainbow table attacks more difficult.