Traditionally most websites that implement an EOSIO smart contract do not offer a key storage service, instead, they integrate with a web wallet. The wallet then stores the keys locally for the user and encrypted. It will decrypt the keys locally only to sign transactions so the web app is never exposed to the private keys.
I would recommend Scatter (...
As the link in your comment explain, 0x80 prefix is Bitcoin convention. (indicating Bitcoin mainnet)
Due to characteristics of elliptic curve, there are only two points which share same x-coordinate. It means that, if you know x-coordinate and sign of y-coordinate, you can derive complete pair of x- and y-coordinate. That's compressed public key. (Oppositely,...
On first glance, you can transfer a token only to a recipient account.
A key can control multiple accounts, and an account can have multiple keys.
However, the "transfer" can actually be tied to account creation.
There are smart contracts which, given some EOS, a public key and a new account name, create an account with that name, buy RAM for it, and stake ...
Steemit currently has a similar functionality, I would look at their coding, as it will be very similar to EOS. Specifically in steemit see: https://steemit.com/steemit/@adept/tutorial-how-to-sent-and-recieve-private-encrypted-messages-on-steemit
It depends on your requirements, if you require a deterministic key that can be used outside of the device there are workarounds, however if you require the private keys remain on the device, the only way to do that is to have the device sign an unsigned transaction as one would a cold wallet.
If you can use the ledger to sign a JSON transaction, then ...
Unfortunately ECAF isn't quite functioning as it was envisioned before the mainnet was launched. The hacker will try to move your tocken to an exchange of his choice once it's get refunded in 72 hours. If you can prove your ownership pre-theft, contact exchange. ECAF will take weeks if best, which is likely to be already too late.
You can write your own contract which can store string (representing your address) in eosio::multi_index table. Table can be accessed easily by RPC call, because the changes are stored in state. (not need to replay all actions to achieve current state)
I captured the http message exchanges for the following cleos command by using TCPDUMP.
cleos --wallet-url http://172.18.0.1:8899 -u http://172.18.0.1:8888 push action shlee create '["shlee", 7, "feed dragon"]' -p shlee
It takes 6 http request/response message exchanges.
Step 1. to nodeos
POST /v1/chain/get_abi HTTP/1.0