Destination address now stored as u8 array

Cargo.toml

@@ -11,7 +11,7 @@ ledger_secure_sdk_sys = "1.0.0"
 include_gif = "1.0.0"
 serde = {version="1.0.192", default_features = false, features = ["derive"]}
 serde-json-core = { git = "https://github.com/rust-embedded-community/serde-json-core"}
-
+hex = { version = "0.4.3", default-features = false, features = ["serde"] }
 
 [profile.release]
 opt-level = 'z'

src/app_ui/sign.rs

@@ -20,6 +20,11 @@ use ledger_device_ui_sdk::bitmaps::{CROSSMARK, EYE, VALIDATE_14};
 use ledger_device_ui_sdk::ui::{Field, MultiFieldReview};
 
 pub fn ui_display_tx(tx: &Tx) -> bool {
+    // Generate destination address string in hexadecimal format.
+    let mut to_str = [0u8; 42];
+    to_str[..2].copy_from_slice("0x".as_bytes());
+    hex::encode_to_slice(tx.to, &mut to_str[2..]).unwrap();
+
     // Define transaction review fields
     let my_fields = [
         Field {
@@ -28,7 +33,7 @@ pub fn ui_display_tx(tx: &Tx) -> bool {
         },
         Field {
             name: "Destination",
-            value: tx.to,
+            value: core::str::from_utf8(&to_str).unwrap(),
         },
         Field {
             name: "Memo",

src/handlers/sign_tx.rs

@@ -32,7 +32,8 @@ const MAX_TRANSACTION_LEN: usize = 510;
 pub struct Tx<'a> {
     nonce: u64,
     pub value: &'a str,
-    pub to: &'a str,
+    #[serde(with = "hex::serde")]
+    pub to: [u8; 20],
     pub memo: &'a str,
 }
 

tests/application_client/boilerplate_transaction.py

@@ -24,7 +24,7 @@ def __init__(self,
             if not 0 <= self.nonce <= UINT64_MAX:
                 raise TransactionError(f"Bad nonce: '{self.nonce}'!")
 
-            if len(self.to) != 42:
+            if len(self.to) != 40:
                 raise TransactionError(f"Bad address: '{self.to}'!")
 
     def serialize(self) -> bytes:

tests/test_sign_cmd.py

@@ -27,7 +27,7 @@ def test_sign_tx_short_tx(firmware, backend, navigator, test_name):
     transaction = Transaction(
         nonce=1,
         value=0.777,
-        to="0xde0b295669a9fd93d5f28d9ec85e40f4cb697bae",
+        to="de0b295669a9fd93d5f28d9ec85e40f4cb697bae",
         memo="For u EthDev"
     ).serialize()
 
@@ -70,7 +70,7 @@ def test_sign_tx_long_tx(firmware, backend, navigator, test_name):
 
     transaction = Transaction(
         nonce=1,
-        to="0xde0b295669a9fd93d5f28d9ec85e40f4cb697bae",
+        to="de0b295669a9fd93d5f28d9ec85e40f4cb697bae",
         value=666,
         memo=("This is a very long memo. "
               "It will force the app client to send the serialized transaction to be sent in chunk. "
@@ -109,7 +109,7 @@ def test_sign_tx_refused(firmware, backend, navigator, test_name):
 
     transaction = Transaction(
         nonce=1,
-        to="0xde0b295669a9fd93d5f28d9ec85e40f4cb697bae",
+        to="de0b295669a9fd93d5f28d9ec85e40f4cb697bae",
         value=666,
         memo="This transaction will be refused by the user"
     ).serialize()