What could cause a paper wallet to become invalid?

[canton]

If I securely load 10 BTC onto a paper wallet today and put it in a safety deposit box for 10 years, could something happen to the Bitcoin protocol itself that would invalidate the balance or make it unrecoverable at the end of that period? (Other than Bitcoin going away altogether of course.)

Put another way: are there some predictable/foreseeable changes we can anticipate as Bitcoin gains popularity and scales such that I should expect to have to bring wallets out of storage and swipe them into newfangled wallets from time to time so as to preserve their validity?

Thanks for helping me understand this.

[kjj]

Basically, no.  The only reason to change away from the current ECDSA math would be if there was a dramatic cryptographic break, which is very unlikely to happen.  And if it did, the response would most likely be to add a new signature type, not to invalidate the old ones.

[TeslaUa]

None that you should expect. If there were not a single spending from that key - the security hangs on RIPEMD-160, SHA256 and ECDSA secp256k1 authenticity and integrity checks. With one or more spendings - on ECDSA secp256k1 authenticity check only. It is highly unlikely that there will be need to change any one of them for something else. Not in 10 years time.

[canton]

It is highly unlikely that there will be need to change any one of them for something else. Not in 10 years time.

Thanks for the replies.

I forgot to ask, what about relying on Wallet Import Format? Any reason for me to withhold placing faith in WIF for the long-term? My thinking is that even if services & software improve on WIF, a 2010's era WIF should still be recognized and supported a decade later... or am I missing something?

[TeslaUa]

I do not think that WIF decoding knowledge will be wiped off of the face of the Earth in 10 years time. You may still duplicate the same key in good old HEX notation if you want to be extra safe.

[niko]

I've got not much to add to the discussion - various formats of private key are easy to convert. Now, without revealing the priv key, you cannot, in principle, always convert between various formats of addresses (since these are one-way functions (hashes) of the public key, which is a one-way function (ecdsa) of the priv key).

[TeslaUa]

Revealing? To whom? Maybe you meant "using privkey"?

[DannyHamilton]

If I securely load 10 BTC onto a paper wallet today and put it in a safety deposit box for 10 years, could something happen to the Bitcoin protocol itself that would invalidate the balance or make it unrecoverable at the end of that period? (Other than Bitcoin going away altogether of course.)

Put another way: are there some predictable/foreseeable changes we can anticipate as Bitcoin gains popularity and scales such that I should expect to have to bring wallets out of storage and swipe them into newfangled wallets from time to time so as to preserve their validity?

Thanks for helping me understand this.

I'd be far more concerned about deterioration or damage of the paper or ink during that time than I would about "something happening to the Bitcoin protocol itself that would invalidate the balance or make it unrecoverable".

[casascius]

I would agree.

I personally would put a password protected paper wallet in at least two different safety deposit boxes (preferably in distant cities), and then give the password to my attorney.  Never know if the bank will burn down or if someone will find a way to snoop in your box.  You won't want them redeeming your paper wallet.  The distant cities part makes it hard for someone to rob you at gunpoint.

[niko]

Revealing? To whom? Maybe you meant "using privkey"?

Revealing it to myself, or anyone else. I am assuming private key is hidden in a tamper-proof manner. Can't use it without revealing it. Doesn't matter for this discussion.

While Casascius' encrypted keys are a great idea that removes the need for hidden priv keys, they do introduce the risk of password being lost or forgotten. This risk is managable, but should not be ignored.

[DannyHamilton]

- snip -
The distant cities part makes it hard for someone to rob you at gunpoint.

It also reduces the risk that a tornado, flood, fire, earthquake, etc. destroys both copies of the paper wallet

[canton]

I'd be far more concerned about deterioration or damage of the paper or ink during that time than I would about "something happening to the Bitcoin protocol itself that would invalidate the balance or make it unrecoverable".

100% agreed. I think water damage is the biggest threat to a paper wallet. I've been doing some experiments to see what I can do to mitigate how water -- even just minuscule drops of condensation from a cold bottle of beer -- can turn an inkjet-printed wallet into squid-ink soup. Inkjet prints are alarmingly delicate.

The reason I'm trying to make sure I understand the technical hazards of paper wallets is so that I can give good all-around recommendations to people printing wallets: from water-proofing to technical to common sense advice.

[interfect]

There's always the possibility that the community will decide to change the rules of the system. If everyone (or whoever controls the community) decides in a few years that lost coins are a big problem and ruining Bitcoin, we could see coins that haven't moved in 10 years from apparently inactive addresses being taken as mining fees, for example.

But barring unpredictable and fairly arbitrary changes to the definition of "Bitcoin" like the above, an old paper wallet would probably still be valid if you could read it.

[aantonop]

There's a project to build better open paper wallets. It includes a backup key stub for secondary storage and will be printed commercially on durable, acid free archival quality paper. Security stickers will protect the code and human-readable keys from water damage, light and prying eyes.

The project is moving quite fast - I estimate the first production run in less than one month.

[wumpus]

I forgot to ask, what about relying on Wallet Import Format? Any reason for me to withhold placing faith in WIF for the long-term? My thinking is that even if services & software improve on WIF, a 2010's era WIF should still be recognized and supported a decade later... or am I missing something?

If you're afraid of that, you should also print out the current spec of the WIF and keep it with your paper wallets, so that in the rare chance that knowledge is lost, it can be reconstructed.

[melvster]

If I securely load 10 BTC onto a paper wallet today and put it in a safety deposit box for 10 years, could something happen to the Bitcoin protocol itself that would invalidate the balance or make it unrecoverable at the end of that period? (Other than Bitcoin going away altogether of course.)

Put another way: are there some predictable/foreseeable changes we can anticipate as Bitcoin gains popularity and scales such that I should expect to have to bring wallets out of storage and swipe them into newfangled wallets from time to time so as to preserve their validity?

Thanks for helping me understand this.

If you're storing it for 10 years, you might want to secure it with TWO keys

[kjj]

I'd be far more concerned about deterioration or damage of the paper or ink during that time than I would about "something happening to the Bitcoin protocol itself that would invalidate the balance or make it unrecoverable".

100% agreed. I think water damage is the biggest threat to a paper wallet. I've been doing some experiments to see what I can do to mitigate how water -- even just minuscule drops of condensation from a cold bottle of beer -- can turn an inkjet-printed wallet into squid-ink soup. Inkjet prints are alarmingly delicate.

The reason I'm trying to make sure I understand the technical hazards of paper wallets is so that I can give good all-around recommendations to people printing wallets: from water-proofing to technical to common sense advice.

Absolutely do not ever use inkjets for anything that you want to last  The only exception is when you can provide stable storage at a cost greater than the value of the printout.

Long term wallets should always be laser printed.  Laser printers work by melting tiny plastic beads onto the surface of the paper.  Laser printed documents can survive water, provided they are not pulped by excessive time or motion.  They can also survive fire, if protected by an ablative fire safe.  Pretty much any normal modern office paper should survive well beyond your lifetime without any heroic measures.

[StarfishPrime]

I'd be far more concerned about deterioration or damage of the paper or ink during that time than I would about "something happening to the Bitcoin protocol itself that would invalidate the balance or make it unrecoverable".

100% agreed. I think water damage is the biggest threat to a paper wallet. I've been doing some experiments to see what I can do to mitigate how water -- even just minuscule drops of condensation from a cold bottle of beer -- can turn an inkjet-printed wallet into squid-ink soup. Inkjet prints are alarmingly delicate.

The reason I'm trying to make sure I understand the technical hazards of paper wallets is so that I can give good all-around recommendations to people printing wallets: from water-proofing to technical to common sense advice.

Waterproof printing is easily done, you just need the right material printed on a laser printer (not ink jet) here's an example:

http://rippedsheets.com/laser/reemay.html#100721-1

(I linked this in your other thread too)

[odolvlobo]

I'd be far more concerned about deterioration or damage of the paper or ink during that time than I would about "something happening to the Bitcoin protocol itself that would invalidate the balance or make it unrecoverable".

100% agreed. I think water damage is the biggest threat to a paper wallet. I've been doing some experiments to see what I can do to mitigate how water -- even just minuscule drops of condensation from a cold bottle of beer -- can turn an inkjet-printed wallet into squid-ink soup. Inkjet prints are alarmingly delicate.

The reason I'm trying to make sure I understand the technical hazards of paper wallets is so that I can give good all-around recommendations to people printing wallets: from water-proofing to technical to common sense advice.

Has anyone tried spraying the paper after printing with acrylic or lacquer to protect it from water?

[niko]

I'd be far more concerned about deterioration or damage of the paper or ink during that time than I would about "something happening to the Bitcoin protocol itself that would invalidate the balance or make it unrecoverable".

100% agreed. I think water damage is the biggest threat to a paper wallet. I've been doing some experiments to see what I can do to mitigate how water -- even just minuscule drops of condensation from a cold bottle of beer -- can turn an inkjet-printed wallet into squid-ink soup. Inkjet prints are alarmingly delicate.

The reason I'm trying to make sure I understand the technical hazards of paper wallets is so that I can give good all-around recommendations to people printing wallets: from water-proofing to technical to common sense advice.

Has anyone tried spraying the paper after printing with acrylic or lacquer to protect it from water?

I know museums and galleries coat photographs (silver or platinum/palladium prints on paper) with some sort of spray.