Merge pull request #414 from Chia-Network/genchal

Add info about how Chia's genesis challenge was calculated

docs/consensus/challenges.md

@@ -42,3 +42,27 @@ class ChallengeChainSubSlot(Streamable):
 As you can see in Figure 4, there are three VDFs being executed concurrently, each of which serves a different purpose. They are explained in detail in the [Three VDF Chains page](/three-vdf-chains).
 
 In the networking protocol, the three VDF proofs are usually passed around together, in what is called an _end of sub-slot bundle_.
+
+## Genesis Challenge
+
+The genesis challenge is the first challenge on a network that uses the Proof of Space and Time consensus. The timelords use this challenge to calculate and broadcast the very first signage point. Chia's mainnet, testnets and simulated networks each have their own unique _genesis challenge_.
+
+The genesis challenge is created arbitrarily, by hashing a preimage. In the case of Chia's mainnet, the preimage included the hash of Bitcoin block [675317](https://www.blockchain.com/explorer/blocks/btc/675317), which was mined shortly prior to the launch of Chia's network. It also included the following message from Bram:
+
+`"Operational error causes Fed payment system to crash" We stand on the shoulders of giants, now let's get farming!`
+
+The exact text of the preimage for Chia's mainnet is:
+
+```
+bitcoin_hash:0000000000000000000942b19f16b83a316acfa31e067c0b766c4dda034dc37f,bram_message:"Operational error causes Fed payment system to crash" We stand on the shoulders of giants, now let's get farming!
+```
+
+The SHA256 hash of this preimage is:
+
+```
+ccd5bb71183532bff220ba46c268991a3ff07eb358e8255a65c30a2dce0e5fbb
+```
+
+This hash is the genesis challenge for Chia's mainnet. The complete JSON data for the genesis challenge is located [here](https://download.chia.net/notify/mainnet_alert.txt). The first block on Chia's mainnet ([block 0](https://www.spacescan.io/block/0)) was created at signage point `2`; it points to the genesis challenge as its previous block. The prefarm was then distributed in [block 1](https://www.spacescan.io/block/1), at signage point `7`.
+
+The genesis challenge for other networks can be found opening `config.yaml` (located in `~/.chia/mainnet/config` for Chia's mainnet and testnets) and searching for `GENESIS_CHALLENGE:` in the section corresponding to the desired network.

docs/resources/faq.md

@@ -24,6 +24,10 @@ Farming uses substantially less electricity than Proof of Work for the same unit
 
 A VDF, also known as a proof of time, is a sequential operation that takes a prescribed amount of time to compute (and which cannot be accelerated by parallelism) and which produces an accompanying proof whose result may be quickly verified. This must be done in a group, for which Chia uses ideal class groups. You can learn about them in our [class group document](https://github.com/Chia-Network/oldvdf-competition/blob/master/classgroups.pdf). [Timelords](/timelord-algorithm) usually run three VDFs at a time for the three internal blockchains of the Chia blockchain. They run as `vdf_client` processes.
 
+### What is a genesis challenge?
+
+A genesis challenge is the first VDF challenge on a network that uses the Proof of Space and Time consensus. For more info about the genesis challenge for Chia's mainnet, see the [consensus section](/consensus-challenges#genesis-challenge) of this website.
+
 ### What is XCH, TXCH, and mojos?
 
 XCH is the currency symbol for Chia. TXCH is the currency symbol currently being used for testnet chias. TXCH has no value and is only used for testing purposes. Chias and testnet chias can be divided up to 12 decimal places (trillionths). The smallest unit of chia, a trillionth of a chia, is called a mojo, as a tribute to [Mojo Nation](<https://en.wikipedia.org/wiki/Mnet_(peer-to-peer_network)#Evil_Geniuses_for_a_Better_Tomorrow>), a decentralized file storage platform created in the early 2000s by Zooko Wilcox, Bram Cohen, and others.