Elliptic Curve Cryptography (ECC) is a key-based encryption method for data. Like RSA, ECC relies on pairs of keys, a public key and a private key, for encryption and decryption of traffic. ECC differs from RSA in the ways the keys are calculated. The keys created using ECC are mathmatically more difficult to crack than those created using RSA. For this reason, ECC is considered to be more secure than RSA.
For more information on elliptic curve cryptography see these blog posts: