Here is how to make a brain wallet 100 times more secure.

btchris

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a.k.a. gurnec on GitHub

Quote from: LitcoinCollector on September 26, 2014, 03:06:37 AM

Don't understand why you go on about affording storage space, it is not about that.
It's about storing the 'private key/password' in your own memory, your brain. The name says it all: brain wallet.

I thought we were having a discussion about comparing the pros (just one: 100k less disk space) and cons (significantly worse security) of a brain wallet compared to a traditional wallet. What you're saying is that it's more about the coolness factor.

I agree, it seems pretty cool to be able to store a bitcoin wallet entirely in wetware. However I stopped using "coolness" and started using logic to help me make decisions somewhere around the age of 15.

If we can't agree on an underlying method of reasoning to use for the decision making process, then I don't think there's anything left to discuss. It'd be like trying to prove evolution to a creationist.

For individuals who do believe in deductive reasoning, traditional wallets are always superior to brain wallets, and therefore brain wallets should never be used. Others are welcome to use whatever method of reasoning and whatever wallet they like.

LitcoinCollector

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Quote from: btchris on September 25, 2014, 09:45:29 AM

Quote from: LitcoinCollector on September 25, 2014, 08:29:26 AM

Quote

The whole point of a brain wallet is store nothing on any device.

Agree

If that's the only advantage, it's a pretty small one compared to the inherent decrease in security.

Can you really not afford the storage space of a 100 kilobyte wallet file?

Don't understand why you go on about affording storage space, it is not about that.
It's about storing the 'private key/password' in your own memory, your brain. The name says it all: brain wallet.

dashen

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Quote from: TrailingComet on June 17, 2014, 09:41:19 AM

Not buying that, brain wallets are just too damn risky!

no venture, no gain, you know.

btchris

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a.k.a. gurnec on GitHub

Quote from: LitcoinCollector on September 25, 2014, 08:29:26 AM

Quote

The whole point of a brain wallet is store nothing on any device.

Agree

If that's the only advantage, it's a pretty small one compared to the inherent decrease in security.

Can you really not afford the storage space of a 100 kilobyte wallet file?

LitcoinCollector

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Quote

The whole point of a brain wallet is store nothing on any device.

Agree

btchris

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a.k.a. gurnec on GitHub

Quote from: Triffin on September 24, 2014, 10:06:21 AM

Quote from: btchris on September 22, 2014, 06:26:32 PM

So.... what is this advantage?

Advantages ??

No downloading a virus embedded in various wallets ..
Hard drive crashes
stolen wallet.dat files
blue screen of death or other local device failure
Utility and ease of use

Triff ..

Regarding "a virus embedded in various wallets": In order to send a transaction from any wallet (brain or traditional), you need to run software. It's then just a question of where you get the software, and do you trust the software's authors. Because traditional wallets are more popular, they have many more eyes on them, and there is much more peer review. Due to this, I'd argue that popular traditional wallets are safer and less likely to have embedded viruses than less popular software.

Regarding stolen wallet.dat files, and malware in general: Brain wallets offer no additional protection over traditional encrypted wallets.

If your brain wallet password is weak, your brain wallet is vulnerable to anybody (which I'm sure you already know). If your traditional wallet password is weak, your traditional wallet is vulnerable only to locally installed malware. In other words, having a wallet.dat file on a hard drive is not less secure than using a brain wallet, as long as the password is strong, and given a weak password, a brain wallet is far more vulnerable.
Both wallet types are equally vulnerable to malware the instant you type your password in order to send bitcoin.

Regarding hardware failures: Backing up an HD wallet is no more difficult than backing up a brain wallet. You simply write it down or print it out (once). Such a backup will protect you against any type of hardware or wetware failure.

Regarding ease of use: this is more a personal opinion -- if you think brain wallets are easier to use, that's your prerogative. However you should weigh this ease-of-use against the inherent security risks of using a brain wallet: is it really that much easier to make it worthwhile?

Triffin

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Quote from: btchris on September 22, 2014, 06:26:32 PM

A brain wallet, with a given password, will always be significantly less secure than a traditional wallet encrypted with that same password. Hopefully this is self-evident to everyone here.
Given this significant disadvantage, there would have to be some significant advantage a brain wallet could give you that no other wallet can before any reasonable person would prefer a brain wallet.
So.... what is this advantage?

I use my 'brain' wallets as 'hot' wallets vs keeping coins on exchanges long term ..
Cold storage is just too cumbersome and I don't have enough 'value' in crypto
or the desire to hold any particular coin long term to where cold storage would be practical ..

So, exchanges for coins I'm trading ..
Brain wallets for off exchange holding ..

Advantages ??

No downloading a virus embedded in various wallets ..
Hard drive crashes
stolen wallet.dat files
blue screen of death or other local device failure
Utility and ease of use

Triff ..

btchris

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a.k.a. gurnec on GitHub

A brain wallet, with a given password, will always be significantly less secure than a traditional wallet encrypted with that same password. Hopefully this is self-evident to everyone here.

Given this significant disadvantage, there would have to be some significant advantage a brain wallet could give you that no other wallet can before any reasonable person would prefer a brain wallet. So.... what is this advantage?

Reynaldo

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Quote from: Phinnaeus Gage on June 17, 2014, 09:18:16 AM

Quote from: davidgdg on June 16, 2014, 07:55:19 AM

Quote from: haploid23 on June 16, 2014, 06:54:23 AM

The reason I completely avoid using brainwallets is because we as humans are not as random as we think. If a word or phrase can be read, then it's not completely random. Even if you have the salt + passphrase format, the "correcthorsebatterystaple" element is still not random. Yes it's more secure, but still not totally random.

Picking words from a dictionary by closing your eyes, flicking through 500 pages and sticking your finger on a "random" page , is random enough for all necessary purposes.

I'd go one step further. Turn the dictionary upside down prior to flipping the pages and poking for words.

Pick 5 words.
Alphabetize them, and remember that order.
Chain them together.
Spell the first, third and fifth (or second and forth) word backwards.
Convert all the o;s and i;s to zeros and ones.
Voilà.

This actually seems like a good idea...Why dont you just hash with sha256 some phrase around 100,000 times ?

ruins

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Quote from: TrailingComet on June 17, 2014, 09:41:19 AM

Not buying that, brain wallets are just too damn risky!

can't agree more, but what if do the transaction offline? that could be more safer.

silversurfer1958

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Isn't This Sha256(BCrypt(PassPhrase)) an easier solution.

Bcrypt or some slower solution, even better if you let the slow down factor for Bcrypt be your birthdate.

luv2drnkbr

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Quote from: jabo38 on June 16, 2014, 02:16:44 AM

I have a way that is better, but if I told you then everybody would know!

Then it is not secure. Security must work even if everybody knows the full algorithm. That's why strong passwords and good entropy sources are necessary.

If the algorithm itself is not known, then it hasn't had a chance to be publicly vetted and may be extremely insecure, and you just wouldn't know it until one day you get hacked and you can't figure out why.

All good security is open source.

boumalo

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Quote from: Razick on September 15, 2014, 08:02:38 AM

If you are storing the salt, why not just store the private key in the first place?

Also, lest someone get the idea to do this without a salt, sha256 does NOT add any entropy, it only makes the result LOOK more random. If someone found out, or just assumed, that people were using sha256 to hash brain wallet passwords, they could brute force your wallet (they might try to brute force all wallets at the same time) by running each attempt through sha256.

Quote

I have a way that is better, but if I told you then everybody would know!

If publishing your method would weaken it, then it is probably not secure to begin with. Security through obscurity is rarely a good idea.

If you say the method you use you weaken at least a little bit your security

Let's say someone from your entourage is trying to sc.am you if you said online that you had a password on a piece of paper at home + a simple password he can get the simple password from you and steal the piece of paper that you have at home

If you didn't say anything and no one knew you had a brain wallet it is safer but the coins will be lost if you die or lose your mind

Razick

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If you are storing the salt, why not just store the private key in the first place?

Also, lest someone get the idea to do this without a salt, sha256 does NOT add any entropy, it only makes the result LOOK more random. If someone found out, or just assumed, that people were using sha256 to hash brain wallet passwords, they could brute force your wallet (they might try to brute force all wallets at the same time) by running each attempt through sha256.

Quote

I have a way that is better, but if I told you then everybody would know!

If publishing your method would weaken it, then it is probably not secure to begin with. Security through obscurity is rarely a good idea.

snakus44

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Could you use a 8 word pass phrase, "thisisthegreatestpassphraseintheworld", run that thru a sha256 calculator, then use all or a portion of that output + "this is the greatest pass phrase in the world"? Maybe repeat with "this1is1the1greatest1passphase1in1the1world"

blumangroup

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'Slow and steady wins the race'

Quote from: odolvlobo on September 12, 2014, 04:21:01 PM

Quote from: TERA on June 16, 2014, 02:11:00 AM

...
Just generate a giant random alphanumber (at least 256 bits to provide maximum entropy) and store it somewhere....

Of course that makes it more secure, but your wallet is no longer a "brain" wallet. If you are going to write down some 256 bit random number, you might as well just write down the private key.

The most effective way to make a brain wallet more secure is to use a different hash algorithm. SHA-256 is designed to be fast and is not suitable. Use one specifically designed for hashing passwords, such as bcrypt.

Exactly. The kind of wallet described in the OP would likely be less secure then a brain wallet that is sufficiently unique. An attacker could potentially find the copy of the "key" that you use with your passphraise and either destroy it or hold it hostage pending you giving them money to allow you to access it again. Also it would encourage someone to use a weak passphraise could find the private key with a small number of "guesses"

odolvlobo

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Quote from: TERA on June 16, 2014, 02:11:00 AM

...
Just generate a giant random alphanumber (at least 256 bits to provide maximum entropy) and store it somewhere....

Of course that makes it more secure, but your wallet is no longer a "brain" wallet. If you are going to write down some 256 bit random number, you might as well just write down the private key (encrypted with BIP-38, if you prefer).

The most effective way to make a brain wallet more secure is to use a different hash algorithm. SHA-256 is designed to be fast and is not suitable. Use one specifically designed for hashing passwords, such as bcrypt.

boumalo

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Think you should think about your brain wallet and the password for months before you send any significant value to the address to be sure you thought about it

Am a big fan of having a few lawyers of security, for a brain wallet don't forget not to talk about your brain wallet or password to anyone

Wonder what method the owners of the biggest addresses used (http://bitcoinrichlist.com/); probably a lot of paper wallet, bitcoin-qt on dedicated devices and a few brain wallets

Dabs

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The Concierge of Crypto

That warp wallet is something that I've been looking for. It takes several seconds to generate a private key, however, it does not create compressed keys.

That is easily fixed, by feeding the non-compressed key into bitaddress.

MaxwellsDemon

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Converting information into power since 1867

Quote from: TERA on June 16, 2014, 02:11:00 AM

There is a really simple way to fix this problem and make your brain wallet 100 times more secure.

The biggest advantage of a brain wallet is that all the information needed to redeem your money is in your brain (arguably, that is the only advantage of a brain wallet).

The biggest disadvantage of a brain wallet is that people tend to forget passphrases (if your passphrase has even slightly reasonable entropy, it is much more likely to be forgotten than brute-forced).

So your method does not enjoy the main advantage of brain wallets, but it does suffer from the main disadvantage. Clever.

You should pick one option: Either make a very strong brain wallet (using some clever key stretching, like warpwallet) and try really hard not to forget it, or make a split paper wallet and store the pieces in several places. That way you at least gain one of the advantages.

Oh and by the way - how is your method any different from storing a BIP38-encrypted private key?

Topic: Here is how to make a brain wallet 100 times more secure. (Read 6470 times)