I was wondering how cex.io manages ethereum service on their website. I know what happens with bitcoin. They have 1 wallet and daemon on their server for each coin. for example bitcoin. Then When I click on the button "deposit" , it generates the address for me. And this address is put into their bitcoin's wallet's main account. So other people's addresses are also put into that main account and they have public/private keys for each address. Why doesn't the same thing happen for ethereum? I read that in ethereum, after generating each new address, there gets created new wallet. Then what? people offer to use smart contracts instead of accounts and wallets. But here comes the question: **How does cex.io implement ethereum wallet service on their server and How Can I do the same?