Topic: Issues with programming, Bitcoin, Private Keys, and Public Keys (Read 4950 times)

Thanks Jonald, I reverted my Python from 3.3 to 2.7.  Though I noticed some interesting things;

Some addresses produce the correct x,y coordinate, some do not.  Its really weird.  I verify the coordinates for the given private key with Bitcoin Address Utility.  

So far, these three addresses produce x,y coordinates that don't match the utility:

218177
823783908234
1257139

But several others do match, go figure.

I run python 2.7.

Thanks Jonald.  If you do find out what version of python you have on your computer that might make a difference for me too, then I can find out what the differences were between your version and mine.

what you said for privkey=3 is the same as what i'm getting -- long number starting with "112",
so i don't know what you're talking about...if you're not seeing those numbers, or seeing them
in e number notation , then you may be right that the python code would need to converted
or somehow configured...should be easy enough... google is your friend...  sorry I don't have
time to help further on that.

JF

Just realized, the problem isn't that I'm getting a solution to the problem, its getting the wrong solution....I think.  The whole result keeps giving me negative y coordinates for the public key, which, mathematically, may make sense, but its not a valid public key in it of itself.  When I add "p", or the mod number to it to provide me with a positive number, it gives me a valid y coordinate, but the wrong y coordinate for the given private key.

Who knows, you may have a different version of Python installed on your computer whereby it works differently than on mine.  I have python 3 installed so I had to modify the code to keep it from erroring out first.

These are the first 5 bitcoin addresses, represented by the number 1 through 5.  The x01 is just a reference to which address and the two following numbers are the x,y coordinates.

x01
55066263022277343669578718895168534326250603453777594175500187360389116729240
32670510020758816978083085130507043184471273380659243275938904335757337482424


x02
89565891926547004231252920425935692360644145829622209833684329913297188986597
12158399299693830322967808612713398636155367887041628176798871954788371653930

x03
112711660439710606056748659173929673102114977341539408544630613555209775888121
25583027980570883691656905877401976406448868254816295069919888960541586679410

x04
103388573995635080359749164254216598308788835304023601477803095234286494993683
37057141145242123013015316630864329550140216928701153669873286428255828810018

x05
21505829891763648114329055987619236494102133314575206970830385799158076338148
98003708678762621233683240503080860129026887322874138805529884920309963580118


When I say I had to modify the code it was just for the "print" command, not the equations itself.  But typing in 3 as the private key gives me "5.506626302227735e+76 3.267051002075881e+76", because what you showed you got for that address did appear to be correct, which is awesome.  My only guess is you have a different version of python installed.

Christianlundkvist, Thanks for putting it like that, I may be able to work with that too (hopefully that'll identify why my code isn't working properly after address 3

The algorithm above for the modular inverse is the Extended Euclidean Algorithm, basically the algorithm will spit out an integer a with the property that a*x + b*p = 1 for some number b.

As for the commas in python, in general a,b = c,d means that a=c and b=d, and you can also do things like swapping the values of a and b by using a,b = b,a.

In our case


can be written more explicitly as


When you test the code, you can check if the value a returned by your function satisfies (a*x) % p == 1.

3 gives me this :  how do you know its wrong?

 
04 11271166043971060605674865917392967310211497734153940854463061355520977588812
1 25583027980570883691656905877401976406448868254816295069919888960541586679410
 

Set it to 3.  It doesn't work.  Or take any random private key and place it there, it doesn't work either.

This is, of course, AFTER one mods the python code to be python 3.0 compatible....

The one I just posted...the only one in this thread.

Here is it again.
https://github.com/wobine/blackboard101/blob/master/EllipticCurvesPart5-TheMagic-SigningAndVerifying.py

Just change the privkey variable to 1 , and you get the data you posted...change it to 2, you also get that
other set of numbers you posted...so the output is as you expected.
 
Now how much Bitcoin do I get ?  Whatever you give me will go to Dob & Noella.

My program is just set to take the first and second Private Keys and public keys and using that data to do "point addition" to produce public keys for private keys 3 through 10.

Private Key "1" has a public x,y key of:
55066263022277343669578718895168534326250603453777594175500187360389116729240
32670510020758816978083085130507043184471273380659243275938904335757337482424

Private Key "2" has a public x,y key of:
89565891926547004231252920425935692360644145829622209833684329913297188986597
12158399299693830322967808612713398636155367887041628176798871954788371653930

If you were to use any bitcoin website or program which takes a private key, and gives you a public key, hash, and address, putting "1" in will get you the first x,y coordintes I showed, and putting in a "2" will produce the second set.  

I do intend to use this programming beyond the first 10 addresses, but if I can't get it to work for the first 10 addresses, it won't work for any other address.

http://coliru.stacked-crooked.com/a/74648b16c2692525


And which python code are you referring to?  One I ran gave me the first 1 or two addresses correctly, but not others, and it was all in floating point number format, I need the full x,y coordinates, not "5.50662630222773x10^11" type stuff.

What 10 addresses do you speak of?  What is the starting point here?
Do you have the public keys, the private keys?  What data do you have
to begin with?

I ran the python code provided above, and it does produce the public
key from the private key using the elliptic curve math.

But I don't think you can produce the x,y coordinates from just
a bitcoin address, as that is a hash of the public key... so, what
are we talking about here?

I've gone through all the info everyone has provided.  That which I can make sense of doesn't work (even when cutting and pasting).

I'm starting to wonder, how much Bitcoin should I be offering for someone to just tweak this code so that (to verify the function of the equations) it produces the first 10 bitcoin addresses' public x,y coordinates? 

I've gone through so many ways of trying to achieve my results and none have succeeded.  my Coliru link in the first post is still the basis and I can't seem to locate anything, that, when applied, produces the desired results.

Quick and dirty example with openssl

Output is

You can check that result is correct on brainwallet.org ( use "correct horse battery staple" as passphrase )

Thank you for all that jonald.  I'm still going through it all.  Either way, I think I'm going to make some progress from all this stuff here.  Its all further confirming that its all about the multiplicative inverse.

here's another resource you might find useful:

https://github.com/wobine/blackboard101/blob/master/EllipticCurvesPart5-TheMagic-SigningAndVerifying.py
https://www.youtube.com/watch?v=U2bw_N6kQL8

I took a look at cryptpop... Actually there is extensive documenation
in the manual section of the website...although, I will admit that
it is quite an abstract library and would be time consuming.

Here's a much more user friendly one in C:

http://jonasfj.dk/blog/2007/12/simpleecdsa-a-simple-implementation-of-ecdsa-in-c/

go into the test.c file, and you will see the example of how
they do it.  Hope that helps.

-Jonald

Just to quote myself:


Your response:


along with



So you don't know if that library is actually the answer.  Yes, I did read through it and couldn't find anything for ECDSA. 

You, and others, are insisting I should use that will resolve the matter quickly and easily, because you believe it obviously exists.  Then you suggest I use one that, as far as you know, will do nothing for me and be substantially more difficult to even figure out than just fixing the equations I've already presented.

Many of you seem to be behaving as theoreticists regarding this matter because you don't actually know the answer to the question.  I do appreciate you having a desire to help me but you're just pointing in different directions in the off chance that the solution is "that way" when you yourself don't even know if the solution is "that way", as you have not even confirmed it yourself.

Quote

Did you download the code library?

Yes I did, and it wasn't the first time I've downloaded that particular library, but I simply guessed I had perhaps overlooked something when you recommended it.

Quote

Did you go to the ECDSA section?

Yes, and no.  There was no apparent "ECDSA" section I could find.

Quote

Have you reviewed the files, classes, and functions?

To the extent that I am capable of doing, yeah, I did.

Quote

Is there any documentation?

Yes, there was, but not much.  What was there that I did understand did not appear to be sufficient to explain and or do even just the multiplicative inverse, let alone simply private key to public key.

Quote

Are there examples?

Yes, but not examples for what I've been trying to do.

Quote

Are there likely candidates for which file or command to use?

A few distantly caught my attention, but as I read through them they weren't what I was looking for.

Quote

I thought you wanted to learn how to write bitcoin related code.

Some, but the only thing I'm seeking help at this time with is converting a private key into a public key utilizing C++.

Quote

It feels like you should be researching yourself and digging in a bit deeper

I've gone as far as it seems I can go at this time, that's why I came to this forum to seek help.  To see if maybe someone could look at my code and go "oh, yeah man, look at that, you have that one equation wrong, here, go to this coliru page where I've corrected that single line".  Or if someone was going to reference a library for me they'd simply say "yeah, use abcdefg.h and type int512_t = privatekey_to_public_key_function( ) ".  I don't expect anyone to do a buttload of research for me, nor am I asking anyone to.  Just that if anyone has any insight and realizes whats going on, I'd really appreciate the help.

I don't know because I've never used that library.

It feels like you should be researching yourself
and digging in a bit deeper...otherwise, whats
the point of this project?  I thought you wanted
to learn how to write bitcoin related code.

As a developer, sometimes you have to research
things.

Did you download the code library?
Did you go to the ECDSA section?
Have you reviewed the files, classes, and functions?
Is there any documentation?
Are there examples?
Are there likely candidates for which file or command to use?

Which header file is for ECDSA secp256k1 (bitcoin's algorithm) and what's the command for converting the given private key into a public key?