What is consensus.BIP34Height?

Question

In the bitcoin source code, I am looking at chainparams.cpp. I can see on line 81 something called consensus.BIP34Height? What is that? I can't figure out what this is.

I'm not sure what else to ask other than what is this? I can't see any mention of it in the developer reference.

score 1 · Accepted Answer · answered Nov 30 '17 at 02:11

1

The specification for BIP34 was created to fix a vulnerability where it was possible to make two transactions with the same TXID. To fix this a nonce was added coinbase transaction, where the height of the block must be encoded in the first bytes of the first transactions input. The definition is for when that soft fork became enforced.

answered Nov 30 '17 at 02:11

Claris

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So consensus.BIP34Height is this nonce? – Oscar Chambers Nov 30 '17 at 02:20
It's when the soft fork became enforced. The nonce is the height. – Claris Nov 30 '17 at 02:21
@eponymous, I read the specification, but it did not contain much info on vulnerability. Can you share how does one create 2 different transactions with same txID? or would you want me to create a new question for it? – sanket1729 Nov 30 '17 at 02:23
http://r6.ca/blog/20120206T005236Z.html contains more details about the exploit. – sanket1729 Jul 01 '20 at 04:36

What is consensus.BIP34Height?

1 Answers1