rofl-appd: Serialize byte data as hex

rofl-appd/Cargo.toml

@@ -13,6 +13,7 @@ anyhow = "1.0.86"
 # TODO: Replace with a released version once it includes UNIX socket support.
 rocket = { git = "https://github.com/rwf2/Rocket", rev = "28891e8072136f4641a33fb8c3f2aafce9d88d5b", features = ["json"] }
 serde = { version = "1.0", features = ["derive"] }
+serde_with = { version = "3.12.0", features = ["hex"] }
 sp800-185 = "0.2.0"
 thiserror = "1.0"
 tokio = { version = "1.38", features = ["rt", "rt-multi-thread", "sync", "time", "macros"] }

rofl-appd/src/services/kms.rs

@@ -3,6 +3,7 @@ use std::sync::{
     Arc, Mutex,
 };
 
+use serde_with::serde_as;
 use sp800_185::KMac;
 use tokio::sync::Notify;
 
@@ -97,9 +98,11 @@ pub struct GenerateRequest<'r> {
 }
 
 /// Key generation response.
+#[serde_as]
 #[derive(Clone, Default, serde::Serialize, zeroize::Zeroize, zeroize::ZeroizeOnDrop)]
 pub struct GenerateResponse {
     /// Generated key.
+    #[serde_as(as = "serde_with::hex::Hex")]
     pub key: Vec<u8>,
 }
 
@@ -115,11 +118,14 @@ pub struct OpenSecretRequest<'r> {
 }
 
 /// Secret decryption and authentication response.
+#[serde_as]
 #[derive(Clone, Default, serde::Serialize)]
 pub struct OpenSecretResponse {
     /// Decrypted plain-text name.
+    #[serde_as(as = "serde_with::hex::Hex")]
     pub name: Vec<u8>,
     /// Decrypted plain-text value.
+    #[serde_as(as = "serde_with::hex::Hex")]
     pub value: Vec<u8>,
 }