Difference between revisions of "Paper wallet"

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A '''paper wallet''' is the name given to a method of storing bitcoin which involves printing a single [[Private Keys|private key]] and bitcoin [[address]] onto paper and depositing funds into a [[Bitcoin Transactions#P2PHK|P2PKH]] script using the address. Funds can be accessed by accessing the physical paper and entering the private key into a wallet. This is usually achieved by scanning a QR code of the private key in [[Wallet import format]].
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A '''paper wallet''' is the name given to a method of storing bitcoin which involves printing a paired [[Private Keys|Bitcoin private key]] and [[Bitcoin address]] onto paper and depositing funds into a [[Bitcoin Transactions#P2PHK|P2PKH]] script using the address. Funds can be spent by accessing the physical paper and entering the private key into a wallet. This is usually achieved by scanning a QR code of the private key in [[Wallet import format]] (WIF).
  
Paper wallets are seen as a secure method of long term storage of funds however there are downsides to using this method.
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== Redeeming bitcoins stored using paper wallets ==
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The best way to redeem the bitcoins from a private key is to use the "sweep" feature of certain wallet software. This process creates a new transaction that sends the entire balance of the paper wallet to a new address controlled by that wallet.
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Various wallets support sweeping private keys including:
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* [https://electrumsv.io/ ElectrumSV]
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* [https://simply.cash/ Simply Cash]
  
 
==Downsides/Risks==
 
==Downsides/Risks==
  
===Printing===
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Paper wallets are generally regarded as a secure method of long-term storage of funds; however, there are downsides to using this method.
  
Paper wallets require using a printer to transfer them to paper. Most printers have internal storage where the image of the wallet could be saved allowing an attacker with access to the printer to see the private key and steal the stored bitcoins. Shared printers such as in schools, offices or internet cafes are also usually centrally logged. If the printer is accessed over WiFi then any radio wave listener could also obtain the private keys and steal the money.
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===Printing and print media===
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Paper wallets require using a printer to transfer them to paper which presents a risk if networked printers are used in an insecure environment.
  
[[Seed phrase]]s avoid this problem by having the user transfer the sensitive information to paper without a printer but via their own handwriting.
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Additionally, while QR codes have a checksum and robust error correction, print media can be damaged by water, soilage or through crumpling or folding of the paper.
  
 
=== Address reuse ===
 
=== Address reuse ===
  
Paper wallets have just one bitcoin address, leading to [[address reuse]].
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Paper wallets have just one Bitcoin address, leading to [[address reuse]].
  
 
=== Poor user experience ===
 
=== Poor user experience ===
  
Dealing with raw private keys can be unintuitive and may lead to loss of funds if not managed properly. It is recommended that users of paper wallets understand how they function before using them as long term funds storage.
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Dealing with raw private keys can be unintuitive and may lead to loss of funds if not managed properly. It is recommended that users of paper wallets understand how they function before using them as long-term funds storage.
 
 
=== Low error correction ===
 
 
 
The private keys are typically printed in small fonts. Sometimes characters may be mistaken for another letter. One single wrong character will invalidate the key. Private keys in WIF format have a checksum but there are a lack of tools for regular users to correct mistakes.
 
 
 
While QR codes have a checksum and robust error correction, they can be damaged by water, crumpling or folding of the paper.
 
 
 
=== Javascript software ===
 
 
 
Most paper wallets are created in a website using [[Javascript cryptography]], which is considered unsafe for anything related to bitcoin.
 
 
 
=== Browser wallets are bad ===
 
 
 
Almost all paper wallets are made by websites, which therefore involves most of the problems associated with [[Browser-based wallet]].<ref>https://www.reddit.com/r/Bitcoin/comments/771c4z/bitaddressorg_beware_of_possible_scam/</ref><ref>https://np.reddit.com/r/Bitcoin/comments/a7xaej/paperwallet_being_hacked/</ref>
 
 
 
== Redeeming bitcoins and withdrawing funds ==
 
 
 
[[File:FirstBitcoinBills.jpg|thumb|right|200px|Casascius holding early paper wallets]]
 
 
 
The best way to redeem the bitcoins from a private key is to use the "sweep" feature of certain wallet software. This sends the entire balance of the paper wallet to a [[deterministic wallet]]. Alternatively the private key could be imported and the entire balance sent to an address in the wallet.
 
 
 
There are various wallets for doing this:
 
 
 
* [[Electrum]] and [[Mycelium]] support sweeping private keys.
 
* [[Bitcoin Core]] supports the RPC call "importprivkey" for this purpose. See [[How to import private keys in Bitcoin Core 0.7+]]
 
* [[BlockChain.info]] and [[Armory]] can also import them directly into wallets.
 
  
 
== Bitcoin ATMs and paper wallets ==
 
== Bitcoin ATMs and paper wallets ==
  
Many bitcoin ATMs use a paper-wallet-like system for delivering bitcoins if the customer doesn't have a bitcoin wallet. The ATMs can print out a private key/address pair onto paper which contain the customer's bitcoins. Ideally the customer would sweep the bitcoins into their own wallet as soon as they can.
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Many Bitcoin ATMs use a paper-wallet-like system for delivering bitcoins if the customer doesn't have a Bitcoin wallet. The ATMs can print out a private key/address pair onto paper which contain the customer's bitcoins. Ideally the customer should sweep the bitcoins into their own wallet as soon as they can.
  
 
== See Also ==
 
== See Also ==
  
* [[Private key]]
 
 
* [[Seed phrase]]
 
* [[Seed phrase]]
* [[Storing bitcoins]]
 
* [[How to import private keys]]
 
* https://bitzuma.com/posts/how-to-spend-a-bitcoin-paper-wallet-in-three-easy-steps/
 
 
==References==
 
<references />
 
  
[[Category:Security]]
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==Attribution==
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This content is based on content sourced from https://en.bitcoin.it/wiki/Paper_wallet under [https://creativecommons.org/licenses/by/3.0/ Creative Commons Attribution 3.0]. Although it may have been extensively revised and updated, we acknowledge the original authors.

Latest revision as of 01:08, 18 November 2020

A paper wallet is the name given to a method of storing bitcoin which involves printing a paired Bitcoin private key and Bitcoin address onto paper and depositing funds into a P2PKH script using the address. Funds can be spent by accessing the physical paper and entering the private key into a wallet. This is usually achieved by scanning a QR code of the private key in Wallet import format (WIF).

Redeeming bitcoins stored using paper wallets

The best way to redeem the bitcoins from a private key is to use the "sweep" feature of certain wallet software. This process creates a new transaction that sends the entire balance of the paper wallet to a new address controlled by that wallet.

Various wallets support sweeping private keys including:

Downsides/Risks

Paper wallets are generally regarded as a secure method of long-term storage of funds; however, there are downsides to using this method.

Printing and print media

Paper wallets require using a printer to transfer them to paper which presents a risk if networked printers are used in an insecure environment.

Additionally, while QR codes have a checksum and robust error correction, print media can be damaged by water, soilage or through crumpling or folding of the paper.

Address reuse

Paper wallets have just one Bitcoin address, leading to address reuse.

Poor user experience

Dealing with raw private keys can be unintuitive and may lead to loss of funds if not managed properly. It is recommended that users of paper wallets understand how they function before using them as long-term funds storage.

Bitcoin ATMs and paper wallets

Many Bitcoin ATMs use a paper-wallet-like system for delivering bitcoins if the customer doesn't have a Bitcoin wallet. The ATMs can print out a private key/address pair onto paper which contain the customer's bitcoins. Ideally the customer should sweep the bitcoins into their own wallet as soon as they can.

See Also

Attribution

This content is based on content sourced from https://en.bitcoin.it/wiki/Paper_wallet under Creative Commons Attribution 3.0. Although it may have been extensively revised and updated, we acknowledge the original authors.