Topic: To create transaction offline and broadcast them on your software wallet (Read 210 times)

First time in my life I heard of something called semi-cold wallets...something like this doesn't exist.
Hardware wallets are cold wallets and they are not connected with system in the same way like USB flash drives, but in secure way.
Some hardware wallets are even not connected with computer or anything else, they are air-gapped devices like Passport, Keystone, Coldcard, etc.
Point of cold storage is that private keys never touches the internet, and that never happens with hardware wallets.

Do you mean Ledger Live software?
As far as I know, the private key is still stored in the hardware wallet, and cannot be generated through software, unless the seed phrase from the hardware wallet is exported to another software wallet.

I have a Ledger Nano X. Even when connected to Electrum, the Private key is not accessible.

You don't need an online wallet or a device with access to the Internet to create and sign a transaction. You can do it offline on an air-gapped device (I suggestusing Electrum). You need access to the Internet only to broadcast the signed transaction.
The moment you import your private key into an online wallet, your brain wallet can no longer be considered a cold/offline wallet.

You can read this guide if you want to learn more about how to use Electrum as cold storage and how all this works:
https://electrum.readthedocs.io/en/latest/coldstorage.html

The title of this section contradicts its content; namely, if you want to make bitcoin transactions offline, you shouldn't import the keys necessary to sign a transaction to an insecure online environment where these keys are going to be intercepted by malicious actors. If they were created on a secure air-gapped computer, you'd better keep them offline even if you no longer need them. Ideally, all that concerns wallet information generation, financial relations, and usage of bitcoin as a medium of exchange, except maybe a transaction broadcasting, should be performed without a user being connected to the Internet. Ownership of bitcoin establishes through the original owner's knowledge of the randomly-generated keys that no one else is able to generate by chance. If you perform such important manipulation online, you can't be sure that you're the only person who can claim ownership or that your keys weren't exposed to the world because of vulnerabilities in communication channels.

This function is usually called "Sweep private key", but it's not the right tool for the job that involves a secure transfer of funds. Your software wallet needs to support importing unsigned transactions and signed transactions in order to correctly communicate with an air-gapped device that holds your sensitive data. With the software wallet, you can create unsigned transactions and broadcast the signed ones, but you never feed it a private key if your goal is to keep your sensitive information offline.

Hardware wallets aren't cold storage, they are semi-cold storage because you still have a device that you connect to a system that is connected to the internet and could be compromised.

Software wallet is software wallet. It is not hot or cold, what makes it hot/cold wallet is the way you use it. For example you can use Electrum as a cold storage if you run it on an air-gap system.

blockr.io is no longer available. I think your source is outdated.

Generally speaking all the steps you posted here are bad if you are using a hardware wallet, things are a lot easier than explained above. You just connect your hardware device to your computer and sign the transaction created online with the device and broadcast it in place. You don't need offline device, you don't need to import keys, ...

With disconnecting your computer from the internet and generating the keys, you don't make your wallet a cold storage.
You should generate your wallet on an air-gapped device. This means that you should use a device which has been always offline and will never get online.  


Your public key is different from your bitcoin address.
Your bitcoin address is actually a hash of your public key.


With doing this, you defeat the purpose of the paper wallet.
Your private keys should never touch the internet.
You should create the unsigned transaction on the online device and sign it on the offline device.

It is good to store your saving of bitcoin in an offline wallet for security from scammers and malware,while your daily spending bitcoin can be stored on a software (hotline) wallet for easy spending.

There are two wallet needed for this transaction to be successful.

1) Cold Storage _(offline)Wallet : This is a wallet that is never connected to the internet,in this wallet your bitcoin is kept offline. Example of cold storage wallet is ledger Nano X.

2) Software (hotline) Wallet : This is a wallet that is connected to the internet (online), example is Electrum.

How to generate your private and public key pairs of a cold storage wallet.

1) Download the software (ledger Nano X),save the webpage that generates the keys,disconnect your internet. After this open and save the webpage on your desktop,in other for you to generate the keys. Your offline Bitcoin address will have both the private key and public key,after generating the public and private keys,these key pairs should not be exposed to the internet for security.

2) Make an offline copy,by printing out the public key and private key in both alphanumeric form and QR form on a paper. Before printing ensure that your computer and printer is not connected to the internet. The paper wallet should be stored in a fire proof safe or you can also have as many duplicates to keep in different places for security.


Note : The public key is your Bitcoin wallet address,this is used to send bitcoin to your wallet
           The private key is the password to your bitcoin wallet,this is used to sign transactions if you spend the bitcoin in your wallet.

                 Funding your offline wallet
If you want to send bitcoin to your offline wallet,the paper wallet you printed out has a public address which is shown in both alphanumeric form and QR form,send the bitcoin to the address of your paper wallet.


https://www.bitcoin.com/get-started/setting-up-your-own-cold-storage-bitcoin-wallet/

     To create transaction offline and broadcast them on your         software wallet

If you want to make transaction from your offline wallet,you should import the private key of your paper wallet, to your software wallet by scanning your private key QR code into the text box provided for private keys on your software wallet that is connected to the internet,or you copy and paste your private keys in the box.

  As long as your software wallet supports importing of private keys,all you need to do is to tap the import button to continue the procedure. If this is done successfully,then any bitcoin in your paper wallet can be spent by sending the bitcoin through your software wallet to the recipient bitcoin address.



https://99bitcoins.com/know-more-send-from-paper-wallet/




     In case the bitcoin which was sent to the software wallet is more than the bitcoin you are sending,you can send your leftovers bitcoin back to your paper wallet and delete the imported key from your software wallet. You can also generate a new paper wallet if you want to, in order to send  your leftover bitcoin to the  new paper wallet.
   If you want to destroy your paper wallet,make sure you back it up manually to avoid losing all your bitcoin.

    For verification of your transaction,you can verify from blockchain.info or blockr.io by copying and pasting your public key in the search field,this shows your blockchain.


I will like your contribution on this thread,if there is a safer way to make transaction offline and broadcast them on your online wallet without a third party having access to your private key.