Asymmetric Encryption

Rivest-Shamir-Adleman (RSA)

A widely used public-key encryption algorithm based on the difficulty of factoring large integers. Used for both encryption and digital signatures.

Diffie-Hellman (DH)

A key exchange protocol that allows two parties to securely establish a shared secret over an insecure channel. Based on the discrete logarithm problem.

Elliptic Curve Cryptography (ECC)

A public-key cryptography approach based on the algebra of elliptic curves over finite fields. Offers equivalent security to RSA with smaller key sizes.

Digital Signature Algorithm (DSA)

A Federal Information Processing Standard (FIPS) for digital signatures. Based on the discrete logarithm problem and used only for signing, not encryption.

ElGamal

An asymmetric key encryption algorithm based on the Diffie-Hellman key exchange. Used for encryption and digital signatures; less commonly used today.

Pretty Good Encryption (PGP)

A data encryption program that provides cryptographic privacy and authentication for data communication. Uses a hybrid of symmetric and asymmetric encryption. Commonly used for email encryption.

EdDSA (Edwards-curve Digital Signature Algorithm)

A modern digital signature scheme using elliptic curves in Edwards form. Known for high performance and security. Used in DNSSEC, cryptocurrencies, and TLS.

Ed25519 and Ed448

Specific instantiations of EdDSA using the Curve25519 and Curve448 elliptic curves, respectively. Provide fast and secure digital signatures.

X25519 and X448

Key exchange protocols derived from the Curve25519 and Curve448 elliptic curves. Used for secure Diffie-Hellman key exchange in TLS and other protocols.

S/MIME (Secure/Multipurpose Internet Mail Extensions)

A standard for public key encryption and signing of email messages. Built into many email clients and uses certificate-based authentication.

TLS/SSL (Transport Layer Security / Secure Sockets Layer)

Cryptographic protocols designed to provide secure communications over a network. SSL is the predecessor of TLS; TLS is used in HTTPS, email, and other secure communications.