Cold Storage Balance

[Sant22]

How can I do this without importing my current private key into to a "live" computer connected to
the internet? That is to say, even if I build a new Linux computer, install core, import the key,
create a transaction (internet disconnected)... connect to the internet to allow it to broadcast - if
my opsec is broken somewhere - some rogue software could still create an alternative transaction
and broadcast that instead.

[JumperX]

you can use some wallets that have "watch only address" feature so you can view the balance of your cold storage without connecting it to the internet, you can try mycelium (android) for example

[defcon23]

you can use some wallets that have "watch only address" feature so you can view the balance of your cold storage without connecting it to the internet, you can try mycelium (android) for example

...or just check your public adress balance on blockchain.info ... 

[twister]

How can I do this without importing my current private key into to a "live" computer connected to
the internet? That is to say, even if I build a new Linux computer, install core, import the key,
create a transaction (internet disconnected)... connect to the internet to allow it to broadcast - if
my opsec is broken somewhere - some rogue software could still create an alternative transaction
and broadcast that instead.

Use Electrum, make two wallets, one normal wallet on the offline machine, other "Watch Only" on the online one, make the transaction on the online one, transfer it to the offline one, sign it, bring it back, broadcast it.

Tutorials here:

http://docs.electrum.org/en/latest/coldstorage.html#cold-storage
http://docs.electrum.org/en/latest/coldstorage.html#create-a-watching-only-version-of-your-wallet

For more security, use an address for one transaction only, send the rest of the balance into the next cold storage address.

[unholycactus]

With Electrum, you can simply import a public address and it will watch the balance for you.

[HelioHash]

There is a few Android apps on Google Play.
You enter address you want to watch, and always
can track balance and estimated price for your BTC and
altcoin wallets.

https://play.google.com/store/apps/details?id=com.alarmred.bitcoinbalance&hl=en
https://play.google.com/store/apps/details?id=org.crouton.lone.mybanknodes&hl=en
https://play.google.com/store/apps/details?id=com.myoid.cryptowatch&hl=en
https://play.google.com/store/apps/details?id=com.wealthico.android&hl=en

[BitcoinNewsMagazine]

How can I do this without importing my current private key into to a "live" computer connected to
the internet? That is to say, even if I build a new Linux computer, install core, import the key,
create a transaction (internet disconnected)... connect to the internet to allow it to broadcast - if
my opsec is broken somewhere - some rogue software could still create an alternative transaction
and broadcast that instead.

Why are you not using a hardware wallet like a $20 Ledger HW.1? Your private keys never leave the secure element of the Ledger. Yes, you can use cold storage with Electrum using two computers but a hardware wallet is more convenient.

[Patatas]

Use the USB and external Ubuntu flash drive technique.As suggested above you can do this either by Electrum or core.Though electrum has easy access mechanisms I'd advice you to use core for backing up the drive for offline wallet.Don't forget to boot your Ubuntu from the liveCD which won't affect your current system.

[gentlemand]

I just get chrome to remember my addresses and click on the relevant box in a block explorer so they show up. Job done.