IRC meeting summary for 2016-03-24


Main topics

  • Softfork status of BIP9
  • v0.12.1, v0.11.3 and v0.10.5 backports
  • Constant time AES library

Short topics

  • Cfields is working on an overhaul of the network stack of bitcoin core. This means a lot of movement of code, but it will make it easier to add additional features. He has a working full-featured branch and he expects he’ll be looking for concept reviews next week. Wumpus and sipa note he got their concept ACK at the Boston meeting.
  • MarcoFalke proposes to switch the python RPC tests to python 3. Wumpus also notes the next release of Ubuntu will no longer ship with python 2. There doesn’t seems to be any build environment that are python 2 only, so developers agree it is best to outright switch to python 3.

Softfork status of BIP9


VersionBits BIP9 allows using the block header version field as a bit array so that miners can indicate readiness for up to 29 soft forks simultaneously. According to the current code and proposal, a miner that isn’t signaling readiness for any soft forks will create ‘version 4 blocks’, that is blocks with the same version as used to trigger and enforce the BIP65 CLTV soft fork.

meeting comments

#7648 received some tested ACKs but still needs more review as the bar is somewhat higher for a softfork than for a random pull request. Jonasschnelli, MarcoFalke, cfields and wumpus stated intend to review it.

Gmaxwell wonders if anyone has checked whether there are still median-time-past violations being mined (BIP113).

meeting conclusion

  • Review #7648
  • Gmaxwell will try and find miners who still mine median-time-past violations.

v0.12.1, v0.11.3 and v0.10.5 backports


As described in the software life cycle document Bitcoin Core developers aim to maintain the latest and previous major release, which currently are 0.12 and 0.11. Individual developers might choose to update previous versions, however this is not a policy rule.

meeting comments

Luke-Jr is checking whether his pull request #7047 for 0.11.3 backports is accurate. Wumpus notes that’s too much for a softfork release and should wait for a minor release after the softfork release. Luke-Jr might also cease to update 0.10 depending on how hard BIP68/112/113 are to backport to 0.10.

The pull-request #7543 to backport BIP68, BIP112, BIP9 and the softfork logic to 0.12 needs review as well. Pull-request #7716 does the same for 0.11 and also needs review.

meeting conclusion

  • Review #7543 and #7716
  • Bump Gentoo stable to 0.11 (from 0.10)

Constant time AES library


OpenSSL has caused many problems and concerns in the past and developers have worked hard to minimize dependency on openSSL by for example introducing their own library (libsecp256k1) for ECDSA signing/verification. Sipa has written an implementation of AES that should replace OpenSSL’s AES version (PR #7689).

meeting comments

A lot of developers would like to extract sipa’s code into a separate library. Sipa and gmaxwell note this is a single file with no intent nor use to grow beyond this. Gmaxwell also states “a well constructed library is a serious amount of work in and of itself”.

Petertodd has raised some concerns about reviewing the code. Although the code is small, it’s still low-level crypto independently written and he thinks there should be an effort to get outside review. Btcdrak notes he asked @isislovecruft from Tor to take a look at it on a paid basis.

meeting conclusion

  • The majority seems to want to create a library for it, although gmaxwell and sipa still disagree.

Comic relief

sipa:           cfields: just PR it! i want to see the code :)  
jonasschnelli   sipa: code:   
cfields         sipa: i'm still frantically coding it :)  
cfields         jonasschnelli: nooooooo. everyone shield your eyes from that :)  
jonasschnelli   cfields: We all know how code during implementation can look. No shame for it!


IRC nick Name/Nym
cfields Cory Fields
btcdrak BtcDrak
gmaxwell Gregory Maxwell
jonasschnelli Jonas Schnelli
petertodd Peter Todd
MarcoFalke Marco Falke
sipa Pieter Wuille
wumpus Wladimir van der Laan
Luke-Jr Luke Dashjr


This summary was compiled without input from any of the participants in the discussion, so any errors are the fault of the summary author and not the discussion participants.