Cryptography is the set of mathematical techniques used to protect data and communications. It includes encryption, hashing, digital signatures, and key exchange, all designed to keep information confidential, verify who sent it, and detect tampering. In modern systems, cryptography underpins secure web traffic, email protection, device authentication, software updates, and stored data protection.
In cyber security, cryptography matters because attackers often target the trust it creates. If keys are stolen, certificates are forged, or weak algorithms are abused, encrypted systems can still be compromised. Defenders rely on cryptography to secure identities, protect long-lived records, and build secure channels between users and services. It also drives planning for emerging risks: advances such as quantum computing could weaken some widely used public-key methods, so organizations track cryptographic dependencies and prepare migration paths before standards change.