Get first Bitcoin address ever exercise added

Author: nopara73

ProofOfOwnership/Program.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using NBitcoin;
 // ReSharper disable All
 
@@ -11,6 +12,9 @@ static void Main()
             SignAsCraigWright();
             VerifySatoshi();
             VerifyDorier();
+
+            /* BONUS: Get the first Bitcoin Address */
+            Console.WriteLine(GetFirstBitcoinAddressEver()); // 1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa
 
             Console.ReadLine();
         }
@@ -40,5 +44,58 @@ static void VerifyDorier()
             var signature = "H1jiXPzun3rXi0N9v9R5fAWrfEae9WPmlL5DJBj1eTStSvpKdRR8Io6/uT9tGH/3OnzG6ym5yytuWoA9ahkC3dQ=";
             Console.WriteLine(address.VerifyMessage(message, signature));
         }
+
+        static string GetFirstBitcoinAddressEver()
+        {
+            /* 
+             * You probably know The Blockchain is a chain of blocks,
+             * All the way back to the first block ever, called genesis.
+             * Here is how you can get it: 
+             */
+            var genesisBlock = Network.Main.GetGenesis();
+
+            /* 
+             * You probably also know a block is made up of transactions.
+             * Here is how you can get the first transaction ever:
+             */
+            var firstTransactionEver = genesisBlock.Transactions.First();
+
+            /* 
+             * You might not know that a transaction can have multiple outputs (and inputs).
+             * Here is how you can get the first output ever:
+             */
+            var firstOutputEver = firstTransactionEver.Outputs.First();
+
+            /* 
+             * You usually see a destination of an output as a bitcoin address             * 
+             * But the Bitcoin network doesn't know addresses, it knows ScriptPubKeys
+             * A ScriptPubKey looks something like this:
+             * OP_DUP OP_HASH160 62e907b15cbf27d5425399ebf6f0fb50ebb88f18 OP_EQUALVERIFY OP_CHECKSIG 
+             * Let's get the ScriptPubKey of the first output ever:  
+             */
+            var firstScriptPubKeyEver = firstOutputEver.ScriptPubKey;
+
+            /*
+             * Actually your wallet software is what decodes addresses into ScriptPubKeys.
+             * Or decodes ScriptPubKeys to addresses.
+             * Here is how you do it:
+             */
+
+            /* 
+             * First it is important to know a ScriptPubKey may contain one or multiple public keys.
+             * Public keys can be encoded into a bitcoin address.
+             * When a ScriptPubKey contains multiple public keys, it is called multi-sig.
+             * So in order to get the first address ever, we can get the first public key ever:
+             */
+
+            var firstPubKeyEver = firstScriptPubKeyEver.GetDestinationPublicKeys().First();
+
+            /*
+             * You can get a bitcoin address from a public key with the network identifier:
+             */
+            var firstBitcoinAddressEver = firstPubKeyEver.GetAddress(Network.Main);
+
+            return firstBitcoinAddressEver.ToString(); 
+        }
     }
 }