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Bitcoin => Development & Technical Discussion => Topic started by: release on January 25, 2021, 06:17:20 AM



Title: Transaction data with X and y coordinates for r and s and weird public key!
Post by: release on January 25, 2021, 06:17:20 AM
Hi guys so I can across a transaction with X and y data for r and s values. Usually I only see it as one value not seperated with a comma. It also shows a z value. Also the pub key is usually shown as either comprises or not (66 or 230 characters) however this address shows a 210 character pub key on all its outgoing transactions.

I am asking because it is strange and I get the feeling that someone with more knowledge may be able to teach me about this as it is definitely something new to me.


Title: Re: Transaction data with X and y coordinates for r and s and weird public key!
Post by: pooya87 on January 25, 2021, 06:24:52 AM
What's the transaction ID?

Edit: I don't know why you thought this simple question was "snob"! As @achow101 also said below, I'll have to see the transaction to be able to say what is weird about it. for example I can't guess what the "230 characters" are, it may simply be a script (such as redeem scripts in spending P2SH outputs) not a public key at all.


Title: Re: Transaction data with X and y coordinates for r and s and weird public key!
Post by: release on January 25, 2021, 06:33:24 AM
What's the transaction ID?

Is this were you act superior because I didn't use the correct term? Bitcoin snobbery by forum elite lol

You know what I mean


Title: Re: Transaction data with X and y coordinates for r and s and weird public key!
Post by: achow101 on January 25, 2021, 06:39:39 AM
What's the transaction ID?

Is this were you act superior because I didn't use the correct term? Bitcoin snobbery by forum elite lol

You know what I mean
Presumably he is asking the question to know what the txid of the transaction that contains the weirdness that you see so that he, and others on this forum, can examine the issue for themselves. This is a common question, and I would have asked it myself so that I can learn about what this weirdness is and explain what is happening.

But if you're going to take every question as a slight against you and think everyone is being snob for asking for additional information, then perhaps it isn't worth answering your question.



Hi guys so I can across a transaction with X and y data for r and s values. Usually I only see it as one value not seperated with a comma.
I would assume that you are looking at a block explorer that is showing more information than others. Can you provide a link to where we can see this for ourselves?

The r value is a point, so it has x and y coordinates. The rules for ECDSA are that r is the x coordinate of a secret nonce k multiplied by the curve generator point G. During verification, this point is recalculated so verifiers will also learn the y value. This block explorer presumably is doing that and displaying it to users even though it is not actually present.

It also shows a z value.
Verifying an ECDSA signatures requires 3 elements: the signature itself, the public key, and the message. Bitcoin transactions encode the signature and public key in the transaction directly. The third component is a modified version of the transaction itself. This modified transaction is computed, then hashed. The resulting hash is known as z. The block explorer you are using is calculating this value and displaying it to users even though it is not explicitly given in the transaction.

Also the pub key is usually shown as either comprises or not (66 or 230 characters) however this address shows a 210 character pub key on all its outgoing transactions.
An uncompressed pubkey is 65 bytes which is 130 hex characters. However the encoding specified by the SECG document does actually say that public keys are encoded with information about the elliptic curve, so it may be that whatever you are looking at is encoding the pubkey in that way. However pubkeys are not encoded that way in transactions, and doing so would be invalid.


Title: Re: Transaction data with X and y coordinates for r and s and weird public key!
Post by: release on January 25, 2021, 06:59:30 AM
What's the transaction ID?

Is this were you act superior because I didn't use the correct term? Bitcoin snobbery by forum elite lol

You know what I mean
Presumably he is asking the question to know what the txid of the transaction that contains the weirdness that you see so that he, and others on this forum, can examine the issue for themselves. This is a common question, and I would have asked it myself so that I can learn about what this weirdness is and explain what is happening.

But if you're going to take every question as a slight against you and think everyone is being snob for asking for additional information, then perhaps it isn't worth answering your question.



Hi guys so I can across a transaction with X and y data for r and s values. Usually I only see it as one value not seperated with a comma.
I would assume that you are looking at a block explorer that is showing more information than others. Can you provide a link to where we can see this for ourselves?

The r value is a point, so it has x and y coordinates. The rules for ECDSA are that r is the x coordinate of a secret nonce k multiplied by the curve generator point G. During verification, this point is recalculated so verifiers will also learn the y value. This block explorer presumably is doing that and displaying it to users even though it is not actually present.

It also shows a z value.
Verifying an ECDSA signatures requires 3 elements: the signature itself, the public key, and the message. Bitcoin transactions encode the signature and public key in the transaction directly. The third component is a modified version of the transaction itself. This modified transaction is computed, then hashed. The resulting hash is known as z. The block explorer you are using is calculating this value and displaying it to users even though it is not explicitly given in the transaction.

Also the pub key is usually shown as either comprises or not (66 or 230 characters) however this address shows a 210 character pub key on all its outgoing transactions.
An uncompressed pubkey is 65 bytes which is 130 hex characters. However the encoding specified by the SECG document does actually say that public keys are encoded with information about the elliptic curve, so it may be that whatever you are looking at is encoding the pubkey in that way. However pubkeys are not encoded that way in transactions, and doing so would be invalid.

Thanks for your post it was informative. Their is definite snobbery here but that is fine.

I'll inspect closer thanks