RSA refers to Rivest-Shamir-Adleman and ECC refers to Elliptic curve cryptography. They are both algorithms which take different approaches to public key crypto

RSA refers to Rivest-Shamir-Adleman and ECC refers to Elliptic curve cryptography. They are both algorithms which take different approaches to public key cryptography. RSA has been in use for longer than ECC and it's considered to be more well understood. However there are some exciting things going on with ECC, for example it is thought that you could have the same or better security as RSA with a much smaller ECC keysize.