diff --git a/CHANGELOG.md b/CHANGELOG.md
index 02feb41..a7ecb32 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,10 @@
 - performance improvement: internally `get_difficulty` was being called
   multiple times while generating `PoW`, now it calls only once.
 
+### Fixed
+- encoding and decoding configuration used internally was causing an
+  error in `PoW` computation
+
 ## 0.2.0
 
 ### Changed
diff --git a/src/lib.rs b/src/lib.rs
index d7256b0..0635cb3 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -140,7 +140,14 @@ fn score(prefix_sha: Sha256, nonce: u64) -> u128 {
 ///
 /// panics if inp.len() < 16
 fn first_bytes_as_u128(inp: &[u8]) -> u128 {
-    bincode::deserialize(&inp).unwrap()
+    use bincode::config::*;
+    DefaultOptions::new()
+        .with_fixint_encoding()
+        .allow_trailing_bytes()
+        .with_no_limit()
+        .with_big_endian()
+        .deserialize(&inp)
+        .unwrap()
 }
 
 // utility function to get u128 difficulty factor from u32