feat: count unique keys

applications/minotari_ledger_wallet/wallet/src/handlers/get_script_offset.rs

@@ -1,6 +1,7 @@
 // Copyright 2024 The Tari Project
 // SPDX-License-Identifier: BSD-3-Clause
 
+use alloc::vec::Vec;
 use core::ops::Deref;
 
 use ledger_device_sdk::io::Comm;
@@ -15,12 +16,15 @@ use crate::{
     STATIC_ALPHA_INDEX,
 };
 
+const MIN_UNIQUE_KEYS: usize = 2;
+
 pub struct ScriptOffsetCtx {
     total_sender_offset_private_key: Zeroizing<RistrettoSecretKey>,
     total_script_private_key: Zeroizing<RistrettoSecretKey>,
     account: u64,
     total_offset_indexes: u64,
     total_commitment_keys: u64,
+    unique_keys: Vec<Zeroizing<RistrettoSecretKey>>,
 }
 
 // Implement constructor for TxInfo with default values
@@ -32,6 +36,7 @@ impl ScriptOffsetCtx {
             account: 0,
             total_offset_indexes: 0,
             total_commitment_keys: 0,
+            unique_keys: Vec::new(),
         }
     }
 
@@ -42,6 +47,13 @@ impl ScriptOffsetCtx {
         self.account = 0;
         self.total_offset_indexes = 0;
         self.total_commitment_keys = 0;
+        self.unique_keys = Vec::new();
+    }
+
+    fn add_unique_key(&mut self, secret_key: Zeroizing<RistrettoSecretKey>) {
+        if !self.unique_keys.contains(&secret_key) {
+            self.unique_keys.push(secret_key);
+        }
     }
 }
 
@@ -99,6 +111,7 @@ pub fn handler_get_script_offset(
         let index = u64::from_le_bytes(index_bytes);
 
         let offset = derive_from_bip32_key(offset_ctx.account, index, KeyType::SenderOffset)?;
+        offset_ctx.add_unique_key(offset.clone());
         offset_ctx.total_sender_offset_private_key =
             Zeroizing::new(offset_ctx.total_sender_offset_private_key.deref() + offset.deref());
     }
@@ -111,13 +124,19 @@ pub fn handler_get_script_offset(
             get_key_from_canonical_bytes::<RistrettoSecretKey>(&data[0..32])?.into();
 
         let k = alpha_hasher(alpha, blinding_factor)?;
+
+        offset_ctx.add_unique_key(k.clone());
         offset_ctx.total_script_private_key = Zeroizing::new(offset_ctx.total_script_private_key.deref() + k.deref());
     }
 
     if more {
         return Ok(());
     }
 
+    if offset_ctx.unique_keys.len() < MIN_UNIQUE_KEYS {
+        return Err(AppSW::ScriptOffsetNotUnique);
+    }
+
     let script_offset = Zeroizing::new(
         offset_ctx.total_script_private_key.deref() - offset_ctx.total_sender_offset_private_key.deref(),
     );

applications/minotari_ledger_wallet/wallet/src/main.rs

@@ -95,12 +95,14 @@ pub enum AppSW {
     ClaNotSupported = 0x6E00,
     ScriptSignatureFail = 0xB001,
     MetadataSignatureFail = 0xB002,
+    ScriptOffsetNotUnique = 0xB004,
     KeyDeriveFail = 0xB009,
     KeyDeriveFromCanonical = 0xB010,
     KeyDeriveFromUniform = 0xB011,
     VersionParsingFail = 0xB00A,
     TooManyPayloads = 0xB003,
     WrongApduLength = StatusWords::BadLen as u16,
+    UserCancelled = StatusWords::UserCancelled as u16,
 }
 
 impl From<AppSW> for Reply {