New Release Candidate: Final zk-SNARK parameters

The Zcash team has been working to finalize the software for the launch of the Zcash blockchain. We are planning to make the launch release available on the morning (PDT) of 28th October, subject to any last-minute technical hitches.

Over last weekend the final zk-SNARK parameters were created in the Parameter Generation Ceremony. The transcripts and software used for the ceremony have been published, and we’ll be making another post with more information on that very soon.

We encourage everyone to test this latest 1.0.0-rc4 release by following the Beta Guide. That will also make sure that you are able to run the software on your system, and have the zk-SNARK parameters (a ~910 MB download) ready for launch.

Two Releases

As part of a strategy to reduce technical risk and to ensure auditability, we have made two releases within a day of each other. Most users should skip from 1.0.0-rc2 directly to 1.0.0-rc4.

1.0.0-rc3 – bug fixes and dependency upgrades

The intermediate 1.0.0-rc3 release included only bug fixes, and updates of libraries that Zcash depends on:

  1. The node metrics screen added in the rc2 release caused a bug when the output was not directed to a terminal, which has been corrected. (#1612)
  2. The version of Berkeley DB has been updated to 6.2.23. (#1637)
  3. The tinyformat library was updated in order to mitigate a potential buffer overflow vulnerability. (#1640, #1349)
  4. A fix for a minor potential race condition was backported from Bitcoin. (#1634)
  5. A couple of portability problems with the script and the Debian packages have been fixed. (#1053, #1537, #1613)
  6. We have eliminated an error-prone case and a confusing error message when spending part of a coinbase output (e.g. mining reward). As a consequence it is now necessary to spend coinbase outputs exactly so that there is no change; the node will not implicitly select a change address. (#1616)
  7. Updates to documentation and examples. (#826, #965, #1152, #1154, #1643)
  8. Network bootstrapping for mainnet. (#1369)

1.0.0-rc4 – zkSNARK Params and Founders’ Reward Addresses

The 1.0.0-rc4 release, which is the one now deployed on the testnet, made some final updates in preparation for the Zcash launch:

  1. The zk-SNARK parameters have been updated to the ones created by the ceremony performed last weekend.
  2. The Founders’ Reward addresses for mainnet have also been updated.

For a more complete list of changes, see our 1.0.0-rc3 and 1.0.0-rc4 release github milestones.

Imminent Launch

In the remaining time before launch, we will only make further changes if they are necessary to correct critical problems that would be an obstacle to Zcash launching successfully. If all goes to plan, the only thing remaining is the mainnet genesis block — the code is done!

It takes some time to generate the genesis block, and build the binaries. We’re going to mint the genesis block and prepare binaries etc. the night before (i.e. this evening, Thursday, Oct 27), and then go to sleep. Then we will get up and release it the next morning, San Francisco time. Keep an eye on our Twitter feed!

To follow our progress, watch the GitHub project and join the forum. To get an email announcement when Zcash Sprout is ready, put your email address in here.

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