Cryptography is the science of securing communication and information through mathematical techniques. It underpins digital security—from online banking and private messaging to blockchain technology.
Key cryptographic concepts:
- Encryption & Decryption
- Transforms readable data (plaintext) into unreadable ciphertext and back.
- Symmetric encryption: Same key for both (e.g., AES).
- Asymmetric encryption: Public/private key pair (e.g., RSA, ECC).
- Hashing
- One-way transformation (e.g., SHA-256) used for integrity checks.
- Cannot be reversed—ideal for storing passwords or verifying file integrity.
- Digital Signatures
- Prove that a message came from a specific sender and wasn’t altered.
- Certificates and PKI
- Public Key Infrastructure is used in HTTPS, SSL/TLS, and digital identity.
- Zero-Knowledge Proofs
- Allow one party to prove they know a secret without revealing it (e.g., in privacy-preserving blockchains).
Why it matters:
- Cybersecurity relies on strong encryption.
- Cryptographic protocols power VPNs, secure email, and blockchain.
- Legal compliance (e.g., GDPR) often requires encrypted data storage.
Learning cryptography is essential for developers in web security, blockchain, finance, and cloud applications. Start with libraries like OpenSSL, libsodium, or CryptoJS to experiment with secure programming.