First Doubts BTCZ

[Ferrarif]

Hi ! im happy to enter this world but after reading alot from different sources i have some important doubts :

My plan is to have cold wallets for the moment , so :  

1 . Do all altcoins have an offline wallet generator ? For e.g does it exist for zencash, btcZ.. ?
2 . Do all altcoins support signing transactions offline with the private keys, and then make them live using an online computer ?
3 . With cold wallets, i would have to make a backup of the wallet each time i make an outgoing transaction ? or every 10 or
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About paper wallets  >  If you have a paper wallet and one day you need to use it, that day youll have to expose the private key online    when making a transaction ?

Thanks  

[gotminer]

Look up the altcoin you want to buy and see if it has an offline/paper wallet generator.  Be careful that you're downloading it from a trusted source.  Generate the wallet keys on a computer that has never been connected to the internet EVER. 

If you're sending from an exchange to a paper wallet, you're sending using the public key, so that's fine.  Never put your private keys on a computer that is connected to the internet, because the private key is what you'll be using to send the coins somewhere else in the future to sell them.  You don't need to "update it" every time you send a currency to a paper wallet either.  You're always sending to the same public address for that wallet and it's recorded in the ledger.  The private key is not recorded in the ledger, the public address is.

And to your other question, yes, you'll be exposing that private key to your internet connected computer when you decide to send the coins back to an exchange to sell them.  Which is fine.  You're not exposing the private key to the public ledger when you do that.

[jseverson]

About paper wallets  >  If you have a paper wallet and one day you need to use it, that day youll have to expose the private key online     when making a transaction ?

Yes, unfortunately. If you want to be able to have an offline wallet that will never expose your private key online, you could create a watching-only wallet (online) and the actual wallet on an air-gapped computer. You create a transaction using your watching-only wallet, sign it with your air-gapped wallet, then broadcast it with your watching-only wallet. Electrum has a tutorial here.

Electrum only works with Bitcoin, unfortunately, but I'm pretty sure there are modified versions specifically made for some alts. I can't vouch for their safety and security though.

Alternatively, hardware wallets make sure your private keys never leave the device, so that's the most straightforward solution available.

[Ferrarif]

Thank you both  . Ok so for the moment i think i will avoid paperwallets if possible just to avoid that private keys online exposure. Yeah @jserverson thats what im trying to find ( "watching-only wallet (online) + wallet on an air-gapped computer for signing. ) but for altcoins. Ive already " like " 10 alts or so, but to start i want to focus on understanding Zencash & btcZ.

I found myzenwallet.io for zencash which i can run locally with the github code on the air gapped computer to generate a wallet address. The same goes for myetherwallet and the code available on github.

Although for btcZ... after reading the paper and the announcement im still scratching my head  :

 > I found the offline github generator , but apparently theres two kind of addresses public t-address and private z-address. And its a little confusing or im missing something :

On the paper + mining guide it says :
* BitcoinZ-mini and BitcoinZ Cold Wallet (this is the github one) cannot be used for mining as t-addresses are needed to mine - the private z-addresses they generate cannot receive mining rewards *

But on github https://github.com/bitcoinz-pod/zgenerate/releases   it says :
 
" Generates public addresses (taddr - starts with t*).
Just run in command line (cmd):

zgenerate

So now you have BTCZ address and you can start mining!" 

Anyway ill be busy at first setting up the air gapped computer, i hope in a couple of days i solved the btcZ doubts and be able to start mining !!

[pooya87]

1 . Do all altcoins have an offline wallet generator ? For e.g does it exist for zencash, btcZ.. ?

what you call "offline wallet generator" doesn't have to be a complicated program designed to generate paper wallets for example. you can use literary any wallet that creates private keys and lets you export them to generate a cold storage.
for example in bitcoin you can download bitcoin core, go offline, generate as many new addresses as you want and export their private key to print, write down,... as your cold storage.

2 . Do all altcoins support signing transactions offline with the private keys, and then make them live using an online computer ?

it is impossible to answer this because altcoins are very different from each other an in order for a user to be able to do this, they have to add this option and make it easy to use. technically it should be possible for all the altcoins because basically you are splitting the steps needed to spend funds into 3 steps:
1. getting the UTXOs and making the raw transction to be signed online
2. signing the tx from step 1 with the keys offline
3. broadcasting the signed tx from step 2 online.
so the wallet program has to have the command (code) that does these 3 separately.

3 . With cold wallets, i would have to make a backup of the wallet each time i make an outgoing transaction ? or every 10 or

it depends!
some altcoins also follow the HD wallets thing that bitcoin uses so if you make a backup of your wallet or Seed or Master private key once you don't need to do it every time. but if they don't have HD capabilities then you will have to make a back up each time you generate a new key pair not make a transaction.

About paper wallets  >  If you have a paper wallet and one day you need to use it, that day youll have to expose the private key online     when making a transaction ?

as i explained in answer to your second question it depends on the wallet. if it has the ability to sign offline (like most bitcoin wallets have) then you never expose your private keys online.