Cloud Wallet

Cloud wallet and MoneyStream

This document describes how cloud wallets can support the MoneyStream application.

important

MoneyStream uses a cash application protocol. That means transactions are to be signed using SIGHASH_SINGLE|ANYONECANPAY or SIGHASH_NONE. All communications must be exchanged over a secure channel (ssl/tls).

The overall application architecture is shown below.

1. The user must be authenticated to the cloud wallet with an authentication token. The user sends the following request to the cloud wallet api.

{

id:"requestid_string",

action:"sign",

amount:satoshis_integer,

max:satoshis_integer,

timelock:timelock_integer

}

id is the requestid. It will be the same for multiple requests. amount is the requested amount in satoshis. max is the maximum satoshis to allow in this request.

2. The cloud wallet returns a signed transaction.

{

id:"requestid_string",

txid:"transactionid_string",

hex:"transaction_hex_string"

}

important

On subsequent requests, the transaction must use the same UTXOs as the first request!

The user must send another request (sign or close) before the timelock. If none is received then the UTXO should be assumed to be spent.

3. The extension will forward the transaction to the web site wallet with additional information that the application needs.

4. (Not shown in diagram). User will send a request to close the request.

{

id:"requestid_string",

action:"close",

txid:"txid_string"

}

How to sign transactions

Transactions must be signed using the timelock value. Adjust funding with change amount as necessary.

If the max amount can be accomodated using one UTXO then the transaction will look like this.

Index	SigHash	Output
0	SIGHASH_SINGLE|ANYONECANPAY	Change Amount

If the max amount requires multiple UTXO then the transaction will look like this.

Index	SigHash	Output
0	SIGHASH_SINGLE|ANYONECANPAY	Change Amount
1	SIGHASH_NONE	(no output)

If the max amount is too large then there will be no output. The sum of the input values will be less than or equal to amount.

Index	SigHash	Output
0	SIGHASH_NONE	(no output)
1	SIGHASH_NONE	(no output)