Merge pull request bitcoin#900 from kallewoof/2003-signet-static-genesis

bip-325: genesis block/message start

Author: luke-jr

bip-0325.mediawiki

@@ -57,6 +57,26 @@ The <code>modifiedMerkleRoot</code> hash is obtained by generating the merkle ro
 
 A block is considered fully validated if the above commitment is found, and its solution is valid. It is recommended that this verification is done directly before or after the witness commitment verification, as the data required to do both is approximately the same.
 
+== Genesis Block and Message Start ==
+
+The genesis block is the same for all signet networks, whereas the message start is defined as the first four bytes of the sha256d of the challenge script as a single data push (see below).
+
+=== Genesis Block ===
+
+* Time stamp: 1534313275
+* Nonce: 100123
+* Difficulty: 1e2adc28
+
+The resulting genesis block hash is 0000032d7f67af9ec7b7152aea0fe7c95b9804ff973265e252f245e0ae61799d, and the block hex is 0100000000000000000000000000000000000000000000000000000000000000000000003ba3edfd7a7b12b27ac72c3e67768f617fc81bc3888a51323a9fb8aa4b1e5e4a3bc3735b28dc2a1e1b8701000101000000010000000000000000000000000000000000000000000000000000000000000000ffffffff4d04ffff001d0104455468652054696d65732030332f4a616e2f32303039204368616e63656c6c6f72206f6e206272696e6b206f66207365636f6e64206261696c6f757420666f722062616e6b73ffffffff0100f2052a01000000434104678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38c4f35504e51ec112de5c384df7ba0b8d578a4c702b6bf11d5fac00000000.
+
+=== Message Start ===
+
+The message start is defined as the first four bytes of the sha256d of the challenge script, as a single push (i.e. prefixed with the challenge script length). Example:
+
+* Challenge script = 512103ad5e0edad18cb1f0fc0d28a3d4f1f3e445640337489abb10404f2d1e086be43051ae
+* Sha256d(len || challenge script) = sha256d(25512103ad...51ae) = 7ec653a59b1912f9db10da2c461ed827d48f9404d5ef0346a6c94aadd4203646
+* First four bytes = the message start = 7ec653a5
+
 == Compatibility ==
 
 This specification is backwards compatible in the sense that existing software can use Signet out of the box.