Cryptography

Cryptography Basics

Learn the core vocabulary and goals of cryptography: plaintext, ciphertext, keys, ciphers, and confidentiality.

What is the P vs NP Problem?

P vs NP asks whether every problem whose solution can be verified quickly (in polynomial time, the class NP) can also be solved quickly from scratch (in polyno…

What is SSL/TLS?

SSL/TLS is a cryptographic protocol that encrypts data in transit between a client and server, verifies the server’s identity using certificates, and ensures t…

Symmetric vs Asymmetric Encryption

Symmetric encryption uses one shared secret key for both encrypting and decrypting data, making it fast but requiring a secure way to distribute that key, whil…

What is Public Key Infrastructure (PKI)?

Public Key Infrastructure (PKI) is the set of roles, policies, and systems needed to create, distribute, validate, and revoke digital certificates that bind a…

What are Digital Certificates?

A digital certificate is an electronic document, typically in X.509 format, that binds a public key to an identity (such as a domain name or organization) and…

Explain the TLS Handshake in Detail

The TLS handshake is the negotiation phase where a client and server agree on a cipher suite, authenticate the server (and optionally the client) via certifica…

WPA vs WEP: How Do Wi-Fi Security Protocols Differ?

WEP (Wired Equivalent Privacy) is a deprecated, cryptographically broken Wi-Fi security protocol using a static RC4 key that can be cracked in minutes, while W…

What is WireGuard?

WireGuard is a modern, open-source VPN protocol designed for simplicity, speed, and a minimal attack surface, implemented in only a few thousand lines of code…

What is DNSSEC?

DNSSEC (Domain Name System Security Extensions) is a set of extensions to DNS that adds cryptographic signatures to DNS records so a resolver can verify a resp…

What Is Content-Addressable Storage?

Content-addressable storage (CAS) identifies and retrieves data by a hash computed from its own content rather than by a location-based path or key, so two ide…

How Are Merkle Trees Used in Distributed Systems?

A Merkle tree is a binary tree of hashes where every leaf holds the hash of a data block and every parent holds the hash of its children’s combined hashes, let…