How can I check the balance of a Monero paper wallet?

Question

If I securely generate a paper wallet address and mnemonic seed, for example using www.moneroaddress.org, and I send a bunch of funds to this paper wallet, how can I check the balance to ensure everything arrived safely? For example, Bitcoin has a transparent blockchain, so I can look up my public key and my balance will display. Does Monero have a similar functionality?

Answer 1

The procedure is a bit more involved for Monero, but you can do this in two ways:

The easy one off solution is to gather the standard address you sent to, the txkey for the transaction (you said you sent the monero, so you should have it: the txkey is the private key of a random keypair generated when you send a monero transaction: you can get it with get_tx_key TXIDGOESHERE in monero-wallet-cli), and the transaction id for the transfer. Then you run this in monero-wallet-cli again:

check_tx_key TXID TXKEY ADDRESS

This will check how much monero was transfered to that address in that transaction. The txkey is what allows you to unscramble the data on the blockchain for that particular transaction.

If you want to send repeatedly to your cold wallet as well as spend, the hot wallet can keep track of these, though for it to work well, you will have to process all spends via that hot wallet, for things not to get out of sync. The current commands for creating, signing, and relaying a transaction signed by a cold wallet transparently handle all of this. However, the interesting case happens when your cold wallet receives a transaction, which you want to detect spend of. You will then have to do the following:

• in the hot wallet: export_outputs OUTPUTS
• copy the OUTPUTS file to the cold wallet computer
• in the cold wallet: import_outputs OUTPUTS
• in the cold wallet: export_key_images KEYIMAGES
• copy the KEYIMAGES flie to the hot wallet computer
• in the hot wallet: import_key_images KEYIMAGES

From then on, the hot wallet should be able to detect a spend of those monero.

As said above, those outputs and key images import/export functions are transparently updated while doing a cold signed transfer, so you only need to do the manual version if you receive in the cold wallet, and want to detect spending of that monero without making an intervening spend.

Answer 2

This answer is for checking the balance of a Monero paper wallet with no other software other than an internet browser. (1) You need to save the transaction id provided every time you send Monero to your paper wallet. (2) To check the balance go to: http://xmr.llcoins.net/checktx.html. (3) On that page you need to enter your transaction id, Monero public address and your private view key. (4) Make a note of the balance. (5) Repeat this for each transaction and add them up. I'm only investing in Monero so thankfully I will only have a few transactions!

Answer 3

You can use a view-key only wallet (you will need to note down the viewkey when creating the wallet). Keep in mind though that currently you cannot tell if a transaction is spent without generating key images.

Answer 4

The other way is getting a copy of the blockchain on to an offline computer

Set up a Linux computer and download the monero core software, fire up the monero daemon monerod and wait for it to sync the blockchain. Depending on the speed of the computer this may take 1-2 days. once that's done, unplug the computer from the network and turn off all wifi/bluetooth capabilities and unplug any USB devices or drives. Next run monero-wallet-cli --restore-deterministic-wallet and enter your mnemonic seed. You may have to wait a few minutes and then you should be able to type 'balance' and see your balance. After that DON'T reconnect the machine to the internet or insert any USB keys