feat: use utf-8 bytes

crates/cdk/src/nuts/nut19.rs

@@ -24,19 +24,20 @@ pub enum Error {
 impl MintBolt11Request {
     /// Constructs the message to be signed according to NUT-19 specification.
     ///
-    /// The message is constructed by concatenating:
-    /// 1. The quote ID
-    /// 2. All blinded secrets (B_0 through B_n)
+    /// The message is constructed by concatenating (as UTF-8 encoded bytes):
+    /// 1. The quote ID (as UTF-8)
+    /// 2. All blinded secrets (B_0 through B_n) converted to hex strings (as UTF-8)
     ///
     /// Format: `quote_id || B_0 || B_1 || ... || B_n`
-    pub fn msg_to_sign(&self) -> String {
+    /// where each component is encoded as UTF-8 bytes
+    pub fn msg_to_sign(&self) -> Vec<u8> {
         // Pre-calculate capacity to avoid reallocations
         let capacity = self.quote.len() + (self.outputs.len() * 66);
-        let mut msg = String::with_capacity(capacity);
-
-        msg.push_str(&self.quote);
+        let mut msg = Vec::with_capacity(capacity);
+        msg.append(&mut self.quote.clone().into_bytes()); // String.into_bytes() produces UTF-8
         for output in &self.outputs {
-            msg.push_str(&output.blinded_secret.to_hex());
+            // to_hex() creates a hex string, into_bytes() converts it to UTF-8 bytes
+            msg.append(&mut output.blinded_secret.to_hex().into_bytes());
         }
         msg
     }
@@ -45,7 +46,7 @@ impl MintBolt11Request {
     pub fn sign(&mut self, secret_key: SecretKey) -> Result<(), Error> {
         let msg = self.msg_to_sign();
 
-        let signature: Signature = secret_key.sign(msg.as_bytes())?;
+        let signature: Signature = secret_key.sign(&msg)?;
 
         self.witness = Some(signature.to_string());
 
@@ -60,7 +61,7 @@ impl MintBolt11Request {
 
         let msg_to_sign = self.msg_to_sign();
 
-        pubkey.verify(msg_to_sign.as_bytes(), &signature)?;
+        pubkey.verify(&msg_to_sign, &signature)?;
 
         Ok(())
     }
@@ -75,7 +76,29 @@ mod tests {
     fn test_msg_to_sign() {
         let request: MintBolt11Request = serde_json::from_str(r#"{"quote":"9d745270-1405-46de-b5c5-e2762b4f5e00","outputs":[{"amount":1,"id":"00456a94ab4e1c46","B_":"0342e5bcc77f5b2a3c2afb40bb591a1e27da83cddc968abdc0ec4904201a201834"},{"amount":1,"id":"00456a94ab4e1c46","B_":"032fd3c4dc49a2844a89998d5e9d5b0f0b00dde9310063acb8a92e2fdafa4126d4"},{"amount":1,"id":"00456a94ab4e1c46","B_":"033b6fde50b6a0dfe61ad148fff167ad9cf8308ded5f6f6b2fe000a036c464c311"},{"amount":1,"id":"00456a94ab4e1c46","B_":"02be5a55f03e5c0aaea77595d574bce92c6d57a2a0fb2b5955c0b87e4520e06b53"},{"amount":1,"id":"00456a94ab4e1c46","B_":"02209fc2873f28521cbdde7f7b3bb1521002463f5979686fd156f23fe6a8aa2b79"}],"witness":"cb2b8e7ea69362dfe2a07093f2bbc319226db33db2ef686c940b5ec976bcbfc78df0cd35b3e998adf437b09ee2c950bd66dfe9eb64abd706e43ebc7c669c36c3"}"#).unwrap();
 
-        let expected_msg_to_sign = "9d745270-1405-46de-b5c5-e2762b4f5e000342e5bcc77f5b2a3c2afb40bb591a1e27da83cddc968abdc0ec4904201a201834032fd3c4dc49a2844a89998d5e9d5b0f0b00dde9310063acb8a92e2fdafa4126d4033b6fde50b6a0dfe61ad148fff167ad9cf8308ded5f6f6b2fe000a036c464c31102be5a55f03e5c0aaea77595d574bce92c6d57a2a0fb2b5955c0b87e4520e06b5302209fc2873f28521cbdde7f7b3bb1521002463f5979686fd156f23fe6a8aa2b79";
+        // let expected_msg_to_sign = "9d745270-1405-46de-b5c5-e2762b4f5e000342e5bcc77f5b2a3c2afb40bb591a1e27da83cddc968abdc0ec4904201a201834032fd3c4dc49a2844a89998d5e9d5b0f0b00dde9310063acb8a92e2fdafa4126d4033b6fde50b6a0dfe61ad148fff167ad9cf8308ded5f6f6b2fe000a036c464c31102be5a55f03e5c0aaea77595d574bce92c6d57a2a0fb2b5955c0b87e4520e06b5302209fc2873f28521cbdde7f7b3bb1521002463f5979686fd156f23fe6a8aa2b79";
+
+        let expected_msg_to_sign = [
+            57, 100, 55, 52, 53, 50, 55, 48, 45, 49, 52, 48, 53, 45, 52, 54, 100, 101, 45, 98, 53,
+            99, 53, 45, 101, 50, 55, 54, 50, 98, 52, 102, 53, 101, 48, 48, 48, 51, 52, 50, 101, 53,
+            98, 99, 99, 55, 55, 102, 53, 98, 50, 97, 51, 99, 50, 97, 102, 98, 52, 48, 98, 98, 53,
+            57, 49, 97, 49, 101, 50, 55, 100, 97, 56, 51, 99, 100, 100, 99, 57, 54, 56, 97, 98,
+            100, 99, 48, 101, 99, 52, 57, 48, 52, 50, 48, 49, 97, 50, 48, 49, 56, 51, 52, 48, 51,
+            50, 102, 100, 51, 99, 52, 100, 99, 52, 57, 97, 50, 56, 52, 52, 97, 56, 57, 57, 57, 56,
+            100, 53, 101, 57, 100, 53, 98, 48, 102, 48, 98, 48, 48, 100, 100, 101, 57, 51, 49, 48,
+            48, 54, 51, 97, 99, 98, 56, 97, 57, 50, 101, 50, 102, 100, 97, 102, 97, 52, 49, 50, 54,
+            100, 52, 48, 51, 51, 98, 54, 102, 100, 101, 53, 48, 98, 54, 97, 48, 100, 102, 101, 54,
+            49, 97, 100, 49, 52, 56, 102, 102, 102, 49, 54, 55, 97, 100, 57, 99, 102, 56, 51, 48,
+            56, 100, 101, 100, 53, 102, 54, 102, 54, 98, 50, 102, 101, 48, 48, 48, 97, 48, 51, 54,
+            99, 52, 54, 52, 99, 51, 49, 49, 48, 50, 98, 101, 53, 97, 53, 53, 102, 48, 51, 101, 53,
+            99, 48, 97, 97, 101, 97, 55, 55, 53, 57, 53, 100, 53, 55, 52, 98, 99, 101, 57, 50, 99,
+            54, 100, 53, 55, 97, 50, 97, 48, 102, 98, 50, 98, 53, 57, 53, 53, 99, 48, 98, 56, 55,
+            101, 52, 53, 50, 48, 101, 48, 54, 98, 53, 51, 48, 50, 50, 48, 57, 102, 99, 50, 56, 55,
+            51, 102, 50, 56, 53, 50, 49, 99, 98, 100, 100, 101, 55, 102, 55, 98, 51, 98, 98, 49,
+            53, 50, 49, 48, 48, 50, 52, 54, 51, 102, 53, 57, 55, 57, 54, 56, 54, 102, 100, 49, 53,
+            54, 102, 50, 51, 102, 101, 54, 97, 56, 97, 97, 50, 98, 55, 57,
+        ]
+        .to_vec();
 
         let request_msg_to_sign = request.msg_to_sign();