Using Elliptic Curve Calculator (in Armory) - 2-of-2 multisig Question

BeeCoin

sr. member

Activity: 308

Merit: 250

Quote from: jackjack on May 27, 2013, 03:35:59 AM

I meant how do you do pubkey->address and privkey->address?

Hi JackJack
ok... suddenly, problem solved!! I've gone through this at least half a dozen times initially.
I don't know what I did different this time - but it works!!
Sorry, for taking your time, but I was going crazy... Wink

And now it works..

Obviously, PrivateKey1*PublicKey2 vs PublicKey1*PrivateKey2 vs PrivateKey1*PrivateKey2 should result in the same Bitcoin Address for the shared key. And now they do... (see below).
thanks again
BeeCoin.

First step: Create two random private keys (5JvuJuiZiyjFzNqnQ16sbqmQ9wQ26dEaqsbikw734Nega4u2gYN & 5JtTHTXeoq792C7Dy2C7ELEu6RgGQYyQiX2aQ8myWRq4GJnuKj9)
Entered them in the "Keys" tab of Armory EC-Calculator in the "Encoded Private Key" section. It was recognized as "Standard base58 key with checksum" and all other keys were generated.

Second step: Multiply PrivateKey1 and PublicKey2
Using "Scalar Multiply EC Point" with Raw PrivateKey1 (92b7f1f77f22afd8275cf628e71664082b442202a49eac567e7e7b37ba559e69) and raw X/Y PublicKey2 (X:fa4bb8fe6da6c646ac63361a16a142d6c04269d02fbc740eed2c4a54ba7dda26 // Y:12fec352c07045d144ee96197a68a6060c89eff887ef3f8c2dfea8bff7965f33).
Result was:
(a*B)x = 68800907c8d450b1c71c9eab88cbb48d7ed7ae33ddd6f92a3553de132214dd56
(a*B)y = 2388823af491f0c105491625eadd7a92add6e6d35926bac0840c17e2254361bc

I've entered the result as "Raw public key (x,y)" in the "Keys" section and calculated the Bitcoin address (1BjwqtjfMifRNW6dPdAYyJV7K8dV98Cbmm).

Third step: Multiply both private keys.
Using "Multiply Scalars (mod n)" I have multiplied both raw private keys (92b7f1f77f22afd8275cf628e71664082b442202a49eac567e7e7b37ba559e69 and 8d288fef6dfed2edffb34f620256975fe9dbe2949f7e61b14b91d0be593d628a).
The result is a shared private key (31ac197e32af979fc9010b39b7a3c84358d9bfb669f59562b4a63fc86a8bf754).

In the "Keys" section, using the calculated raw private key, I've calculated the Bitcoin address (1BjwqtjfMifRNW6dPdAYyJV7K8dV98Cbmm).

And yes... it matches!!!

jackjack

legendary

Activity: 1176

Merit: 1233

May Bitcoin be touched by his Noodly Appendage

I meant how do you do pubkey->address and privkey->address?

BeeCoin

sr. member

Activity: 308

Merit: 250

Quote from: jackjack on May 27, 2013, 03:02:35 AM

What you do seems ok, do you use the same 'compressedness' for both?

That's kind of what I suspect but I wasn't able to put my finger on the problem.

Quote from: jackjack on May 27, 2013, 03:02:35 AM

How do you calculate the addresses?

You can reconstruct the whole calculation using the data in the OP.
In Armory Elliptic-Curve Calculator, I've used the second function, called "Scalar Multiply EC Point", using PrivateKey1 and PublicKey2 in X/Y raw form.

jackjack

legendary

Activity: 1176

Merit: 1233

May Bitcoin be touched by his Noodly Appendage

What you do seems ok, do you use the same 'compressedness' for both?
How do you calculate the addresses?

BeeCoin

sr. member

Activity: 308

Merit: 250

Anyone can help me with the calculation? Still not solved...

BeeCoin

sr. member

Activity: 308

Merit: 250

Hi folks

I was excited to see this post on the Elliptic Curve Calculator in Armory:
https://bitcointalksearch.org/topic/elliptic-curve-calculator-ui-now-part-of-armory-66862

Based on the 2-of-2 Multisig example, I was able to create a shared public key. However, I was not able to get the corresponding shared private key.

So, here is the data I have used:

Code:

1:
PUBLIC
1MFpXAU8VaYUfKxzpPvZSZXpvbZJVE34jM
de3001c3402b4ff42c91bfb60f18943a209bafc6
PRIVATE
5JvuJuiZiyjFzNqnQ16sbqmQ9wQ26dEaqsbikw734Nega4u2gYN
92b7f1f77f22afd8275cf628e71664082b442202a49eac567e7e7b37ba559e69

2:
PUBLIC
18J9jxfYQw9e9fv1YYm9QxNBkFoxyTEZix
50073f899897517dc8bc743e5690773515042432
X:fa4bb8fe6da6c646ac63361a16a142d6c04269d02fbc740eed2c4a54ba7dda26
Y:12fec352c07045d144ee96197a68a6060c89eff887ef3f8c2dfea8bff7965f33
PRIVATE
5JtTHTXeoq792C7Dy2C7ELEu6RgGQYyQiX2aQ8myWRq4GJnuKj9
8d288fef6dfed2edffb34f620256975fe9dbe2949f7e61b14b91d0be593d628a

Based on this, I've calculated the shared public key in the EC Calculator:

Code:

==> PRIVATE 1 * PUBLIC XY 2 (second function):
X:f8c61d46fc0c7f866b6ec34e191279e9a9ef1ff9d263aadc189669cd6bb4b7db
Y:161b41cae92dbb41e7b0584be2e5adbb9c83718c19eb1c6f3f82e31a403c6d96
==>BTC:1GmWADL3wvwm6dCxgf5XxirW8bBD34rRgU

Now, I've tried calculating the shared private key but it didn't match:

Code:

==> PRIVATE 1 * 2 (first function):
31ac197e32af979fc9010b39b7a3c84358d9bfb669f59562b4a63fc86a8bf754
==>BTC:1BjwqtjfMifRNW6dPdAYyJV7K8dV98Cbmm

Did I do something wrong? How do I achieve a matching pair of secret public/private keys?

-BeeCoin.

Topic: Using Elliptic Curve Calculator (in Armory) - 2-of-2 multisig Question (Read 1727 times)