ARPA is a Secure Computation Network Compatible With Blockchains They propose a blockchain-based secure computation network of Multi-party Computation (MPC). ARPA cryptographically enables private smart contract, unprecedented data-at-use privacy protection, as well as scalable computational sharding.
EXMR is the official token of GetCryptoPayments® gateway, and its main function of this payment gateway will be to integrate a wide universe of currencies and tokens through a competition, with the acquisition of Ethereum Monero for that purpose. The online merchants and the local store can receive payments on most cryptocurrencies, safely and quickly with a low rate. This payment gateway will allow retailers worldwide to accept payments in Ethereum Monero, Bitcoin, Ethereum, Litecoin, and altcoins. There will be no fees for payments made in EXMR.