diff --git a/Cargo.toml b/Cargo.toml
index b8252d39..1526e604 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,7 +22,7 @@ subtle = { version = "2.5", default-features = false }
 # optional dependencies
 der = { version = "0.7", optional = true, default-features = false }
 generic-array = { version = "0.14", optional = true }
-num-traits = "0.2"
+num-traits = { version = "0.2", default-features = false }
 rand_core = { version = "0.6.4", optional = true }
 rlp = { version = "0.5", optional = true, default-features = false }
 serdect = { version = "0.2", optional = true, default-features = false }