I just need a user-friendly way to sweep bitcoins from a offline paper wallet onto the Blockchain, without having to expose your private key, whilst you are online. ....
The bitcoins in the paper wallet are already on the blockchain. What you are asking is about moving the private key from a paper wallet to some kind of wallet that can be used for transactions.
You can create a transaction off line. Hence it is possible to never expose a private key to an online wallet.
https://bitcointalk.org/index.php?topic=944915.0
It only makes sense to me that a Paper wallet is meant to be created offline to increase the security and therefore it makes further sense that the Sweep/Import option should also be done offline first and then encrypted before you go online again.
The automated Encryption and Decryption of the Private key to import/sweep the wallet, would reduce the risk of the private key being compromised during the process to sweep/import these wallets, when you go online.
Offline
Step 1 - Scan QR code on Paper wallet and retrieve the Private key
Step 2 - Insert Private key into App
Step 3 - App Encrypt Private key
Step 4 - Insert Bitcoin Address where coins will be swept to
Online
Step 5 - Go online
Step 6 - App still running, Click on "Sweep Paper Wallet"
Step 7 - Application automatically decrypt the Private key and sweep the coins from the paper wallet onto the Address specified in Step 4
Done
If you look at a site such as https://walletgenerator.net/, then the tab entitled "Paper Wallet" you will see the BIP38 Encrypt option.
That allows storing paper wallets encrypted. At the moment I don't have time to do testing but if I recall correctly some wallets, at the moment of sweeping such a QR code, will ask for the decryption password.
Thanks for the URL, it does not address the issue of securely "sweeping or importing" the Private key, but it looks better than Bitaddress.org
Can anyone validate if this site is as safe as Bitaddress.org? Both have links to the Github repositories for the Source code, but I do not know if the code for this wallet generator was checked.
The site only tells you the standard answer, when you want to spend the coins from the paper wallet :
You will need to import your private key in a real client, that you can download from the currency website. The exact method to do that will depend on the client. If there is no integrated method, you can usually fall back to the debug console and use the command importprivkey [yourprivatekey].
I am still looking for a secure way to do offline sweeping/importing of private keys as discussed.