Attached is the (signed) announcement of the random beacon. Also, it's been timestamped using OpenTimestamps.
Sean
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Hi all, I covered the random beacon in a previous post on the mailing list: https://lists.z.cash.foundation/pipermail/zapps-wg/2018/000262.html The security proof for the ceremony requires that a random beacon is queried and applied at the end, like a simulated participant. The beacon's output can be somewhat influenced by an adversary, and it won't impact our security margins much. In any case, it's likely that security holds even if the beacon is totally compromised, we just haven't had time to write a proof of this yet. Also, if you think we used a bad beacon, you can just apply a better beacon yourself. I still wanted a strong and rigid beacon so there weren't any questions. This means using one source for the beacon. The strongest source I can imagine is a "delay function" applied to a Bitcoin block. As long as the delay function takes a long time to compute with respect to the average time between Bitcoin blocks (10 minutes) it becomes difficult to argue that a miner could have influenced the beacon much, if at all. The ideal delay function is an iterated SHA256 hash over the Bitcoin block hash. I think 2^42 iterations should be sufficient. (Note that this is not a proof-of-work function! The hashes are not parallelizable, so there's a practical limit to how fast this beacon can be computed on classical hardware.) The result of the beacon (the SHA256 digest at the end) will seed a ChaCha20 PRNG. I've written code for the beacon and placed it into my git repository. I'll be applying this to the block hash of block #514200. Hash of the most recent response file: 77fc8ccb a8550a6c 7255b82b 3352bb83 075fdc07 9a84beec 8175287a 6cf9b47f 89f49a29 1025da84 994753d8 3d9169d1 b370345f 367cb2db c18b2137 33c5b303 Here's the (SHA256) hashes of the current code on my powersoftau repo: src/lib.rs: 5f1a7703e78a4f5ad8b083b838b2672c35e75cf8dc17a55a32a38f5e30aa2ecb src/bin/beacon.rs: 6043fe25ae68b547c74632f0573a5b65fc6f5a040c468d65ab9c2b6942f5d1dc src/bin/compute.rs: c0eeb6b496052a3f1a2f4b311690af94d639ef2a0d606c488f06776cf1684dba src/bin/new.rs: 1bca0dc358548b1cd4fd6c7e2c1a053c244927e457a61ef6973f7bba539f1079 src/bin/verify_transform.rs: dd73283c5f618af43147327063f7659d73870f9684c85f5c80514d9da16d1746 Cargo.toml: 7b686d1b308fcfe5023929100b84cfafbbfac8feae454ded4ceb6e7bece897d6 Cargo.lock: 346e03229383df01620de095c217a63b035c520db7dabdb24ec9d710567b342a Sean Bowe -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEA5XeClAnvgwfWvsDlWhCV9j4sDEFAlquxTsACgkQlWhCV9j4 sDEnzxAAqEv7Bs/7l9xDQBfQ+7ty1Pz0+qdv6AhnjOTx1h+LggS7C4xWKr4cK+VR tFZk3ReTXSLmxANjZKj8dPi0A4/17fo415RhaR09JbHNqIft+0MtnvU5josJPUxJ NGQcTU3nvcPJK5SPv8PhWgKeHeogeeJ80b4PlVAsOwZOQ5eC92kcGuoSDfkOP+nS J7b8zErIfPsiPg4tbAYMINDxJSey6VI6Pqd02ayXYUSKBoAYe6dWQXfc+yvv2oTO ShfpGzzX6UQLz0GCz2AVwZOXF6Ij6dBOcYO3qkaxXOsKRbLAu4ky7WdBOqKjAzrJ OHnY5XRcOemF7dWNfmrMd+0hW12XGcpJoKKIU13//dq7E2aKLxHx4ErnII80mQvW vRLClQuZcHCi1L4Vtq9bpzKztRsYWdqZtSET3cwKPWt3+8Vw+z+fzhWksFlaQheC i1IQYmzppxTkgFP5cn4NQuGp4s20ZcVJmJLC/4uw8zrBmG09v7EV0VIhcK8ixA4S gbXJZzZOU/mBoFuBD/2XQr7+KP0cgbpeV8/Ww/UbPt3zUma6AgVQkCYx2ToxaZeF JmflkykJAcAJ9411ngQpHdJmgUxgRb+vcF5iozvDTA8LfRTKZAawFbG2dGBA++wJ +7MOsPCwnCHLbmfvsARdW+YviZ+qvmJl5mZF12tVmGauh/5oGRU= =V+gB -----END PGP SIGNATURE-----
beacon.txt.asc.ots
Description: application/vnd.oasis.opendocument.spreadsheet-template