ED25519 is a high-speed high-security public-key signature system. It uses elliptic curve cryptography and it is supported by OpenSSH since 6.5.
ED25519 generates small keys of 32 bytes and allows fast single-signature/batch verification, very fast signing and fast key generation.
ssh-keygen -t ed25519ED25519 should be prefered over RSA, DSA and ECDSA.