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/crypto/chacha.rs

@@ -1,67 +0,0 @@
-use chacha20poly1305::{ChaCha20Poly1305, Key, Nonce};
-use chacha20poly1305::aead::{Aead, NewAead};
-use std::fmt::{Debug, Formatter};
-use std::fmt;
-#[allow(unused_imports)]
-use log::{debug, error, info, trace, warn};
-
-/// A small wrap-up to use Chacha20 encryption for domain names.
-#[derive(Clone)]
-pub struct Chacha {
-    pub cipher: ChaCha20Poly1305
-}
-
-impl Chacha {
-    pub fn new(seed: &[u8]) -> Self {
-        let key = Key::from_slice(seed);
-        let cipher = ChaCha20Poly1305::new(key);
-        Chacha { cipher }
-    }
-
-    pub fn encrypt(&self, data: &[u8], nonce: &[u8]) -> Vec<u8> {
-        let nonce = Nonce::from_slice(nonce);
-        match self.cipher.encrypt(nonce, data.as_ref()) {
-            Ok(bytes) => { bytes }
-            Err(_) => {
-                warn!("Error encrypting data!");
-                Vec::new()
-            }
-        }
-    }
-
-    pub fn decrypt(&self, data: &[u8], nonce: &[u8]) -> Vec<u8> {
-        let nonce = Nonce::from_slice(nonce);
-        match self.cipher.decrypt(nonce, data.as_ref()) {
-            Ok(bytes) => { bytes }
-            Err(_) => {
-                warn!("Error decrypting data!");
-                Vec::new()
-            }
-        }
-    }
-}
-
-impl Debug for Chacha {
-    fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
-        fmt.write_str("ChaCha20Poly1305")
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use crate::crypto::Chacha;
-    use crate::to_hex;
-
-    #[test]
-    pub fn test_curved_chacha() {
-        let buf = b"178135D209C697625E3EC71DA5C760382E54936F824EE5083908DA66B14ECE18";
-        let keys1 = Chacha::new(b"178135D209C697625E3EC71DA5C76038", );
-        let bytes = keys1.encrypt(b"TEST", &buf[..12]);
-        println!("{}", to_hex(&bytes));
-
-        let keys2 = Chacha::new(b"178135D209C697625E3EC71DA5C76038");
-        let bytes2 = keys2.decrypt(&bytes, &buf[..12]);
-
-        assert_eq!(String::from_utf8(bytes2).unwrap(), "TEST");
-    }
-}