What Is Cryptography? Understanding Methods and Applications
Get a high-level overview of cryptography, including common algorithms, use cases, and the role cryptography plays in everyday security.
Cryptography Overview
Cryptography is the study and practice of techniques for securing information and communications. It encompasses methods for confidentiality (keeping data secret), integrity (detecting tampering), authentication (verifying identities), and non-repudiation (proving actions occurred).
Modern cryptography relies on well-studied mathematical algorithms and standardized protocols rather than obscurity. When used correctly, it provides strong guarantees that are computationally infeasible for attackers to break with current technology.
Common Cryptographic Methods and Primitives
Core cryptographic building blocks include symmetric ciphers (such as AES), asymmetric algorithms (such as RSA and elliptic curve cryptography), hash functions (such as SHA-256), and message authentication codes (MACs). Each primitive serves a different purpose, from encrypting data to signing messages or deriving keys.
Protocols like TLS, SSH, and PGP combine these primitives in structured ways to provide secure channels, authenticated sessions, and encrypted email. The strength of a system depends not only on the algorithms themselves but also on how they are combined and implemented.
Real-World Applications of Cryptography
Cryptography underpins many everyday technologies: it secures web browsing, mobile payments, VPN connections, wireless networks, and stored passwords. Digital signatures verify software updates and documents, while encrypted messaging apps protect personal conversations from eavesdropping.
For organizations, effective cryptographic key management is as important as the algorithms themselves. Keys must be generated with sufficient randomness, stored securely, rotated when appropriate, and revoked if compromised. Poor key practices can undermine even the strongest cryptographic tools.