diff --git a/intel-sgx/dcap-ql/Cargo.toml b/intel-sgx/dcap-ql/Cargo.toml
index 7c1a578b..4f0a9725 100644
--- a/intel-sgx/dcap-ql/Cargo.toml
+++ b/intel-sgx/dcap-ql/Cargo.toml
@@ -45,7 +45,7 @@ byteorder = "1.1.0" # Unlicense/MIT
 anyhow = "1.0"   # MIT/Apache-2.0
 lazy_static = "1"   # MIT/Apache-2.0
 libc = { version = "0.2", optional = true }        # MIT/Apache-2.0
-mbedtls = { version = "0.12", default-features = false, features = ["std"], optional = true }
+mbedtls = { version = "0.12", default-features = false, features = ["std", "x509"], optional = true }
 num = { version = "0.2", optional = true }
 num-derive = "0.2"  # MIT/Apache-2.0
 num-traits = "0.2"  # MIT/Apache-2.0