diff --git a/curve25519-dalek/Cargo.toml b/curve25519-dalek/Cargo.toml
index bf6451f72..7f77bdf9f 100644
--- a/curve25519-dalek/Cargo.toml
+++ b/curve25519-dalek/Cargo.toml
@@ -34,6 +34,7 @@ sha2 = { version = "0.10", default-features = false }
 bincode = "1"
 rand = "0.8"
 rand_core = { version = "0.6", default-features = false, features = ["getrandom"] }
+hex = "0.4.2"
 
 [build-dependencies]
 platforms = "3.0.2"