Added second keypair for encryption of domain names.

Changed keys file format to include second pair of keys, it will be in TOML now.
Made many adjustments to block and transaction structures.
Changed block serialization to binary format for hashing/mining.
Removed old build dependencies.

src/blockchain/block.rs

@@ -16,16 +16,16 @@ pub struct Block {
     pub difficulty: u32,
     pub random: u32,
     pub nonce: u64,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub transaction: Option<Transaction>,
-    #[serde(default, skip_serializing_if = "Bytes::is_zero")]
-    pub prev_block_hash: Bytes,
     #[serde(default, skip_serializing_if = "Bytes::is_zero")]
     pub hash: Bytes,
     #[serde(default, skip_serializing_if = "Bytes::is_zero")]
+    pub prev_block_hash: Bytes,
+    #[serde(default, skip_serializing_if = "Bytes::is_zero")]
     pub pub_key: Bytes,
     #[serde(default, skip_serializing_if = "Bytes::is_zero")]
     pub signature: Bytes,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub transaction: Option<Transaction>,
 }
 
 impl Block {