diff --git a/go/common/crypto/mrae/deoxysii/asymmetric_test.go b/go/common/crypto/mrae/deoxysii/asymmetric_test.go
index 2cf6f513c1d..70cd6d5c182 100644
--- a/go/common/crypto/mrae/deoxysii/asymmetric_test.go
+++ b/go/common/crypto/mrae/deoxysii/asymmetric_test.go
@@ -12,6 +12,7 @@ import (
 )
 
 func Test_DeriveSymmetricKey(t *testing.T) {
+	// use the same test Hex string for rust at: oasis-core/runtime/src/common/crypto/mrae/deoxysii.rs
 	p, _ := hex.DecodeString("c07b151fbc1e7a11dff926111188f8d872f62eba0396da97c0a24adb75161750")
 	var privateKey [32]byte
 	copy(privateKey[:], p)
diff --git a/runtime/Cargo.toml b/runtime/Cargo.toml
index 91f238b6070..ff1fb33c1cd 100644
--- a/runtime/Cargo.toml
+++ b/runtime/Cargo.toml
@@ -60,7 +60,6 @@ oid-registry = "0.4.0"
 rsa = "0.5.0"
 base64-serde = "0.6.1"
 lru = "0.7.5"
-hex = "0.4"
 
 [target.'cfg(not(target_env = "sgx"))'.dependencies.tokio]
 version = "1"
@@ -68,6 +67,7 @@ features = ["full"]
 
 [dev-dependencies]
 # For storage interoperability tests only.
+hex = "0.4"
 jsonrpc = { version = "0.12.1", features = ["simple_uds"] }
 tempfile = "3.3.0"
 
diff --git a/runtime/src/common/crypto/mrae/deoxysii.rs b/runtime/src/common/crypto/mrae/deoxysii.rs
index 8b08a27525a..774492d32ac 100644
--- a/runtime/src/common/crypto/mrae/deoxysii.rs
+++ b/runtime/src/common/crypto/mrae/deoxysii.rs
@@ -93,6 +93,7 @@ mod tests {
 
     #[test]
     fn test_drive_symmetric_key() {
+        // use the same test Hex string for golang at: oasis-core/go/common/crypto/mrae/deoxysii/asymmetric_test.go
         let private_key_buffer = <[u8; 32]>::from_hex(
             "c07b151fbc1e7a11dff926111188f8d872f62eba0396da97c0a24adb75161750",
         )