Asymmetric Encryption: RSA and Elliptic Curves

Asymmetric encryption uses a mathematically linked key pair: a public key (shared freely) and a private key (kept secret). Data encrypted with the public key can only be decrypted with the private key, and vice versa.

RSA (Rivest–Shamir–Adleman, 1977) is based on the difficulty of factoring large prime numbers. Security depends on key size: RSA-2048 is current minimum; RSA-4096 for high-security use. RSA is slower than symmetric encryption — used for key exchange, not bulk data.