diff --git a/src/lib.rs b/src/lib.rs
index f7e7396..ae5e99f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -17,7 +17,7 @@ use arrayref::array_ref;
 // extern crate blake; // compatible version with Blake used at circomlib
 use blake2::{Blake2b512, Digest};
 // use hex_literal::hex;
-use std::{cmp::min, io::Bytes};
+use std::{cmp::min, io::Bytes, str::FromStr};
 
 use num_bigint::{BigInt, RandBigInt, Sign, ToBigInt};
 use num_traits::One;
@@ -161,6 +161,15 @@ impl ToDecimalString for Fr {
         BigInt::from_str_radix(&hex_str, 16).unwrap().to_string()
     }
 }
+pub trait FrToBigInt {
+    fn to_bigint(&self) -> BigInt;
+}
+
+impl FrToBigInt for Fr {
+    fn to_bigint(&self) -> BigInt {
+        BigInt::from_str(&self.to_dec_string()).unwrap()
+    }
+}
 
 impl Serialize for Point {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>