Topic: Matching public key with directory.io - why so difficult? (Read 3703 times)

Try asking that in an LBC thread.

For example here:  https://bitcointalk.org/index.php?topic=1877935.0;topicseen

Would it be possible to use LBC for personal purposes, ie without connecting to the LBC servers?

thank you all I stay on the wire because I test and come bring my results here

See https://en.bitcoin.it/wiki/Technical_background_of_version_1_Bitcoin_addresses specifically step 7.

How calcul checksum of address ?

Are Bitcoin addresses random?  You tell me:

The private key is huge random number.  
The public key is therefore basically a random point on a huge elliptic curve.
The public key is then hashed, this creates a random number based on the random point on the curve.
The result of the hash is then hashed again, creating a random number based on the first hash.
The result is then hashed again creating a random number based on the result of the second hash.

Finally the result of the third hash is encoded into an ASCII string starting with 1 or 3.

Do you see now?

You can search for "vanity address generation" here on the forums.

Vanity address generation:

Let's say I want to find a Bitcoin address that looks like this "1BurtWxxxxxxxxxxxxxxxxxxxxxxxxxxxx"


Else you have found one of the almost infinite number of private keys that happen by chance to have "1BurtW" as the first 6 characters of the Bitcoin address.

I did this years ago.

Here is the result:   1BurtWEejbnKeBRsvcydJvsNztB1bXV5iQ

NOTICE that I have the private key and the Bitcoin Address so this is a valid Bitcoin Address and I have the private key so any Bitcoins sent to this address are "mine" in the sense that I can spend them - since I know the private key.

Here is another possibility:


Notice that this is a valid Bitcoin address in that you can send Bitcoins to it and people have, to the tune of 13.1251233 BTC (!)

https://blockchain.info/address/1BitcoinEaterAddressDontSendf59kuE

However, in this case, the private key is not know, for all practical purposes it is impossible to find the private key, the private key will never be found so these 13.1251233 BTC are lost forever.

Back in the old days when it did not cost anything to do a transaction and Bitcoins were only worth a couple of dollars each I actually placed one of my favorite poems into the blockchain, there to reside forever.  Here it is:


As noted above the private keys for these addresses cannot be found, ever, so these 0.00000004 BTC are lost forever.

Two more interesting points:

1) If you take any Bitcoin address, for example 1BitcoinEaterAddressDontSendf59kuE then, by design, there is not just one possible private key that will give you this exact Bitcoin address.  There are approximately 2⁹⁶ = 79,228,162,514,264,337,593,543,950,336 different private keys that will give you this exact Bitcoin address!  Even though there are that many different private keys that would allow you to own and spend the 13.1251233 BTC at that address it is, for all practical purposes, impossible to find even one of them!

Blows the mind, right?

2) Very long vanity addresses have been found.  Here are the records.  Note that the private keys for these addresses are known by the owners because they were found, by chance, by generating trillions of random valid private keys and then checking the Bitcoin addresses calculated from the private keys.

They are unpredictable, unless your wallet has a severely flawed random number generator and ends up generating the same address over and over again. Else, the addresses generated are random. Vanity address generators have an estimated time since there is a fixed range of characters for which an address can have. They can effectively give a very vague estimate of the time based on the probability.

the addresses are they really random or say that we could find an address of the type "11111" every X private key?

Generating a private key takes very little time.  In the case of directory.io the private keys for the page are simply calculated from the page number.  In the case of a real key pair generation the private key is a secure random 256 bit number.  In the case of the LBC the private key started at 1 and incremented from there (they are currently creating and testing key pairs with the private keys around 2^53.22 or 10,490,987,492,010,478).

Once you have the private key, which is very easy, then you have to calculate the public key which is a point on an elliptic curve.  The equation looks simple (Public Key) = (Private Key) * G but it is a bit involved since G is a point on a curve and * is the scalar multiplication function defined over the points on the curve.

Remember all public keys are point on a curve so they are X, Y coordinates.  For elliptic curves for every X coordinate there are exactly two possible Y coordinates which are easy to calculate so to "remember" a specific point on the curve we can either remember the X and the Y coordinate or just the X coordinate and a single bit to tell us which of the two possible Y coordinates to use.  This means there is a "compressed" form of the public key (the X coordinate and one additional bit = 256 + 1 = 257 bits) and and "uncompressed" form of the public key (the X coordinate and the Y coordinate = 256 + 256 = 512 bits).

Once you have the public key you can now generate the Bitcoin address which is defined as a specific ASCII encoding of the triple hashing of the public key plus some check bytes.

Since for every public key there are two ways we can represent it (compressed and uncompressed) this means that for every public key there will be two possible forms for the Bitcoin address.  If you start with the compressed form of the public key you end up with the compressed version of the Bitcoin address.  If you start with the uncompressed form of the public key you end up with the uncompressed form of the Bitcoin address.

What was your question again?

would it be possible to create the same site by not generating private keys but hash160?

No, if you try and crawl that site there will be a (practically) infinite number of pages.  Google alone has about 45000 pages index, all dynamically generated. 
https://www.google.com/search?source=hp&q=site%3Adirectory.io&oq=site%3Adirectory.io

Kind of like Google has about 42 million pages from finance.yahoo.com indexed.  Most are dynamically generated for various stock symbols and the related pages for each, etc:
https://www.google.com/search?q=site%3Afinance.yahoo.com

Wow! Thanks heaps.

No?
https://github.com/saracen/directory.io

You obviously didn't read my posts! I was thinking about USING directory.io as an offline wallet generator - IF I could get the code offline. Unfortunately, the creator hasn't made the code downloadable.

At the very first moment when you visit directory.io to find the page number of your offline created private key, it will be very easy for the admin of the page to steal your funds immediately PLUS your offline generated key is not offline anymore. There is no need to repeat the visit, because the attacker (admin) can simply check all visited directory.io pages and check the balance of all private keys on that very page.

These are just ideas and this is just a discussion. I'm the type of person that delves and delves until I find myself answering other people's questions on whatever it is I'm investigating.

A random private key will never be as memorable to me as something I create myself. So there's a trade-off either way you go.


Once again, you're assuming I'm reusing this public address over-and-over again or that I'm advertising it. This is my storage wallet and not an address for people to send me funds. True, if I bring them out of hibernation it increases their vulnerability. Then I go down the path of p2p wallets, etc and find a new cold address to send my savings to.

I don't understand why you are so fixated on choosing your own private key that is memorable. Why not instead generate random private keys until you generate something that you find memorable. That is far more secure than you choosing something memorable.

It can be stolen the moment you decide to spend the coins and have to enter you private key into some software. Even if you are keeping the coins in long term storage, at some point in the future you will want to move those coins out of storage to do something with them. Whenever you do that, you expose your private key and it can be stolen.

Similarly, the same argument can be made for randomly generating a private key and keeping it on a storage medium that never touches the internet.

There is also still a significant privacy loss even if you are only using that address for receiving. For starters, everyone that sends you money will know how much money you have. Furthermore you are reducing the privacy of everyone that transacts with you because anyone will be able to look at their transactions and immediately know who they were paying and how much.

Thanks for your detailed response. I'm sure others will find it useful too.


>>>>First of all, you are essentially sending your private key to a remote web server (directory.io).

Not if I'm doing the public-private key generation locally on an air-gapped, unconnected computer - one of the reasons for my posts above. I would like to get hold of that code for personal use, but the creator has hidden it, unlike other websites that randomly generate public-private key pairs. I actually think that I could create the code if I really put my mind to it, something I might consider if I can't get that code.

>>>>Secondly, you still need to load that private key into a wallet software in order to spend from it.

Not if I'm keeping it purely for storage and not transacting with it.

>>>>Thirdly, because the private key is in an unencrypted form, if the private key is stolen, then the thief can spend your coins immediately. With wallet encryption, if your coins are stolen, you still have time to move them as strong encryption and a strong password will protect your private keys.

How would a thief steal it if it's committed to memory and the public key has only ever been used once - to deposit the money? You're assuming I'm using it for transacting. That wallet is cold and the private key has never touched the Internet.

>>>>Lastly, you would be reusing the exact same address over and over again which will lead to significant privacy loss.

Not if I simply put the bitcoin there for long term storage.
-----------------------

The more I think about it, the better my idea becomes - for storage purposes, that is. Perhaps not for transacting.

The page number and location that you find memorable, even if a "huge" string of numbers, is probably something that many other people would find memorable. Regardless of what number you choose, it will not be as secure as randomly generating a private key. What you are doing is similar to brain wallets which are notoriously insecure. Except your method is less secure as it does not include any key stretching or additional things to possible add randomness (e.g. hashing) that brain wallets do.

There's nothing stopping you from randomly generating a private key and then figuring out its location on directory.io. Or randomly generating the page number and randomly generating the key index on directory.io so that you can memorize them for your key. That would be more secure than you choosing the location manually. You can even keep generating random numbers until you find one that is memorable to you. That is much more secure than you choosing your own private key.

Furthermore you are still vulnerable to many attacks (even the same ones that you thought you weren't vulnerable to) with your scheme.

First of all, you are essentially sending your private key to a remote web server (directory.io). The owner of that website can see that your browser would be visiting the same page over and over again. It would not be hard for them to just search through the private keys on that page and see which ones have coins and then steal them. In fact, any man in the middle could do this. The site doesn't even use https so anyone sniffing traffic on your internet connection (e.g. shared wifi) would be able to see exactly what page you are on and then just scan those private keys.

Secondly, you still need to load that private key into a wallet software in order to spend from it. You will probably have the private key on your clipboard, and the private key will be held in insecure places and in insecure memory. With a proper wallet software that generated your private key, the private key will remain in that software's memory (unless you export it). Your private key would then be able to be stolen by keyloggers and clipboard loggers which constitutes far more viruses than coin stealing viruses as coin stealing viruses much find specific files to steal your coins. This means that your key is much more vulnerable to viruses on your computer. Additionally you would still be vulnerable to traditional coin stealing viruses because most wallet software will write imported keys to a wallet file so normal coin stealing viruses can go steal those wallet files.

Thirdly, because the private key is in an unencrypted form, if the private key is stolen, then the thief can spend your coins immediately. With wallet encryption, if your coins are stolen, you still have time to move them as strong encryption and a strong password will protect your private keys.

Lastly, you would be reusing the exact same address over and over again which will lead to significant privacy loss. There's a reason that nearly all wallet software gives you a new address every time you want to receive coins and every time it makes a change output.

Questions about security vs. accessibility have been plaguing the computer security industry for decades. In the end it is simply up to you to determine such risks for yourself, there is no formula that will answer it for you.

Although humans are notoriously bad at randomness, human minds are really good at seeing patterns, even when they are not there (like shapes in the clouds). You can use that to your advantage to generate a random password using a machine and then remember it by imagining patterns in the keys, pretending that the characters actually have some meaning. This will help you remember it.

Another way you could exploit a human mind is by obtaining muscle memory of your keys. All you need to do is type them regularly, even if it is on a detached keyboard, so it will stay in your "muscles". All my passwords exist only in my subconscious, they were randomly generated and they are long as hell, I have no idea what they are. This resulted in some loses of accounts and inability to type them on a phone keyboard, but as long as you have a physical copy as well, you should be fine. It is unlikely you would lose both at the same time.