Implement basic PoW module

Author: ChronosXYZ

Cargo.lock

@@ -6,8 +6,12 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+arrayref = "0.3.7"
 async-std = { version = "1.12.0", features = ["attributes"] }
 async-trait = "0.1.68"
+bytes = "1.4.0"
 futures = "0.3.28"
+hmac-sha512 = "1.1.4"
 libp2p = { version = "0.51.3", features = ["async-std", "dns", "macros", "noise", "ping", "tcp", "websocket", "yamux"] }
+log = "0.4.17"
 multiaddr = "0.17.1"

Cargo.toml

@@ -1,5 +1,7 @@
 use std::error::Error;
 
+mod pow;
+
 use futures::StreamExt;
 use libp2p::core::upgrade::Version;
 use libp2p::swarm::keep_alive::Behaviour;

src/main.rs

@@ -0,0 +1,24 @@
+use bytes::Bytes;
+use hmac_sha512::Hash;
+use log::info;
+
+// Function to do PoW for sending messages into network
+fn do_pow(target: u64, initial_hash: Bytes) -> (u64, u64) {
+    info!("PoW has started");
+
+    let mut nonce: u64 = 0;
+    let mut trial_value = u64::MAX;
+    while trial_value > target {
+        nonce += 1;
+        trial_value = u64::from_be_bytes(
+            Hash::hash(Hash::hash(
+                [&nonce.to_be_bytes()[..], &initial_hash[..]].concat(),
+            ))[0..8]
+                .try_into()
+                .unwrap(),
+        );
+    }
+
+    info!("PoW has ended");
+    return (trial_value, nonce);
+}