Add Debug impls

src/utils.rs

@@ -1,8 +1,10 @@
-mod small_primes;
+use std::fmt;
 
 use rand_core::RngCore;
 use rug::{Assign, Complete, Integer};
 
+mod small_primes;
+
 /// Wraps any randomness source that implements [`rand_core::RngCore`] and makes
 /// it compatible with [`rug::rand`].
 pub fn external_rand(rng: &mut impl RngCore) -> rug::rand::ThreadRandState {
@@ -200,6 +202,18 @@ impl CrtExp {
     }
 }
 
+impl fmt::Debug for CrtExp {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("CrtExp")
+    }
+}
+
+impl fmt::Debug for Exponent {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("CrtExponent")
+    }
+}
+
 #[cfg(test)]
 mod test {
     #[test]