Bitcoin Forum

Being a photographer, many pros suggested not shooting a wedding on just one SDHC card.  Such as shooting at a wedding, shoot on multiple cards just in case one card goes corrupt.  But some internet mathematician pointed out that it's more mathematically safe to shoot on one SDHC card.  The low failure rate is such, that you increase your possible failure rate with each additional card (Ie.  Using 4 8gb cards in place of 1 32gb card increases the odds of a card failure by 4x).

Would this apply to wallets?   I looked up risk probability on Google but couldn't figure it out.

Right now, the bulk of my funds are stored in (1) Electrum and (2) a brain wallet that never touched the Internet.  I also use blockchain.info (3) & (4) as hot wallets for spending.  I also use Mycelium, Multibit and Dark Wallet but those are just intermediaries with no money ever held there.  Personally, I feel most safest with electrum, and maybe the cold storage brain wallet.  A little afraid though that some future quantum computer could some day figure out the random seeds on Electrum and the Brain Wallet.

think it depends on the physical media they are, not the wallet type, unless they have some kind of software bug that in some way could corrupt your dat file, what I think is really unlikely.

the good news is that you can buy many backup medias and save all your wallets privates keys in every one of the medias, so decreasing the overall failure prob.

You are 4x as likely to lose 1/4 of the wedding photos if you use 4 SD cards.  But you're 10000000x more likely to not get paid if you lose 100% of the wedding photos by using only 1 SD card.

Brain wallets are easily guessable, you should move your funds into something else immediately.

You increase the odds of having a single card fail by using more than one. The likelihood of more than one failing is infinitely lower than failure of multiple cards.

By increasing your number of wallets you are obviously increasing the liklihood that you could lose some coins. But on the same token, you are dramatically decreasing the chances that you would lose them all.

Let's pretend that each wallet has a 50% chance of loss (and also make a bunch simplifying assumptions).

If you have one wallet then you have a 50% chance of losing at least some coins and a 50% chance of losing all coins.
If you have two wallets then you have a 75% chance of losing at least some coins, but only a 25% chance of losing all coins.

So with multiple wallets,, you chances of losing some coins increases, but the chances of losing all coins decreases.

there is just a simple way to save your btc, just keep it in a cold storage(away from kids) and burn the printed private keys. then it wont matter on how many wallets you make, ur btc will always be safe.

Even with a thousand wallets you are still pretty safe.

They are safe until they dont store their private keys in their email ids, but they can be even unsafe in the cold storage(i remember how much my friend cried when the hard disk in which he had 15BTC got corrupt).

That only goes for wallets without a backup tho. If you have 4 wallets with 1/4 coins in each wallet and one is corrupted, you lose 1/4 of your coins.

If you have one wallet saved on 4 different cards and one goes corrupt, you still have 100% of your coins.

So as long as you have a good number of backups, everything is fine.

Failed SDHC card doesn't exist ...  ::) it's use a "removal SDHC" in a poor card reader that's it destroy the SD card.
Use ... the cable provide with the camera  ;D

I use a compact flash in a netbook (before the SSD age) to store and use a Windows XP ... since 3 years.
Since i buy SD card and have crashed all my card reader, not a single card haven't been destroy.

That is an excellent point. A backup reduces your risk.

This is not rocket surgery.

You're very simply spreading your risk and its a trade-off.  You're more likely to have any
one thing (wallet, card, whatever it is) fail, but if it does, your total loss is only a fraction of the whole.
And when it comes to money, it is generally prudent to spread your risk which is why
smart investors diversify their portfolios.

If you really want the math:

Assume you had five wallets, each with a 1 percent chance of failure.
(99% chance of success of safe storage).

.99 to the fifth power is approx 95%, so now it's a 5% chance you'll
Lose 20% or more of your money! rather than 1%.

But .01 to the fifth power means it's only 0.00000001% chance
You'll lose ALL YOUR money.  So you decide.   :)

As far as Electrum, I highly recommend it and also using the cold storage brain wallet.  Great choice!
Just make sure the cold storage really is cold and you have a secure way to recover your own seed.

I wouldn't worry about quantum computers.  The 12-word electrum seed is chosen from a 1626
dictionary, giving you 128 bit security, with an additional 16 bits of security added in with key
stretching for a total of 144 bits of security.  The maximum security you can get with bitcoin
private keys right now is 160 bits...therefore if quantum computers ever became a threat,
all of bitcoin would have to upgrade, not just electrum.

Also, to the critics of brain wallets, Electrum does it right using computer generated entropy
(you CANNOT enter your own arbitrary seed), so no one can guess it....and for those that say don't
use brain wallets because you never know if the method could change to retrieve the
private keys, I've provided a stand-alone python script using the current electrum method,
just in case you don't trust the electrum developers would consider backwards compatibility. (see the electrum subforum)

In this thread:

A bunch of people who failed to consense on whether they were talking about many COPIES of one wallet, multiple different wallets with a little wealth in each, or some combination thereof.

I am pretty sure OP meant multiple different wallets.

With many copies of the same wallet, the situation get worse because the wealth can be stolen from any of the wallets, and there is no distribution of risk.  That said, backups are obviously needed in some form.   But that's another thing I like about electrum.  Your secret seed serves as the backup, so no additional backups are needed which could increase the risk.

Off-topic I know, but this seems to me to be a complete myth.

Chosen at random from my old Longman's Dictionary (pages opened at random)...deform lockage sedate daunt captive

The dictionary has 70,000 words:

70,000^5 = ~ 2*10^24

Try brute-forcing that  ;)

Thats security on the order of 2^90.
Still strong, but electrum has 2^144.
so you should choose 8 or 9 words
from that dictionary.

Well you have solved only half the problem. For most people, a set of words that can be reliably memorized is going to be easy to brute force.

Are you saying the average person can't memorize  a 12 word pass phrase?

This was my thought as well... I'd rather have a bigger chance to lose a LITTLE than a smaller chance to lose absolutely everything.

But then again you could use backups of each SD card as well and create a bigger buffer (same with wallets).

If I can remember two or three of the five words I could alway brute force the rest if necessary

As long as you have enough entropy, I do agree brain wallets are perfectly fine. The reason why many people including myself advise against it is that in general people are too lazy to properly choose random words instead substituting them for words they believe to be random or ones from famous films/songs/poems et al.

...which is why electrum doesn't allow that.

It's not just that.  Everyone can work on cracking a brainwallet from anywhere.  To crack a wallet.dat file they have to have a copy of it.

Anyone can also work on cracking a private key from anywhere too without the wallet file.
Bitcoin private keys have 160 bits of security, maximum.

So, you just have to make sure your brain wallet has enough
bits of security (128-bit or more).

Brain wallet is VERY dangerous

Move your BTC ASAP to address generated with https://bitcoin.org/en/download (https://bitcoin.org/en/download) and just print on paper (with big fonts) your private key (at least 3 copy)

Also is good idea to generate 4 or more wallets instead of one (I have 55 BTC in 4 offline wallets)

Sure, but if you have a 160 bit brainwallet then what is that, 14 - 15 words?  You'll have to write it down.  So that's a paper wallet, where you're encoding the private key with words instead of base58.  It's not a brainwallet.

The key is to not have too many wallets so that you cant keep track of them all. Having a ridiculous amount is just going to be tedious and stressful.

A backup of the brainwallet, perhaps stored steganographically, or broken into sections and given to various trusted parties, is a good thing.

Whether you still consider it a brainwallet or not is semantics.

Yes, but if you have your coins in 7 wallets like mine one loss won't be to bad. All mine are online though and that's obviously more prone to loss than offline.

Choose words from different languages.

Brain wallets should really only be used if you have serious concerns about your computer being compromised in the future (and this is a legitimate concern).

An effective brain wallet must be memorized, otherwise it is no better then a paper wallet or a password protected wallet on your computer.

People use "mining farms" to calculate the public key of many brain wallets and monitor the blockchain for when btc is transferred to the address. When it is they use a script to push a TX to transfer the coins to an address they control.