From 2aeb373e73cdf30367c1df434bdc4c398945000f Mon Sep 17 00:00:00 2001
From: Andrew Poelstra <apoelstra@wpsoftware.net>
Date: Sat, 6 Sep 2014 11:35:36 -0500
Subject: [PATCH] Fix encode/decode of ChildNumber so that hardened keys do not
 become normal ones

---
 src/wallet/bip32.rs  | 42 +++++++++++++++++++++++++++++++++++++++++-
 src/wallet/wallet.rs |  4 +---
 2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/src/wallet/bip32.rs b/src/wallet/bip32.rs
index 4d9c0ed..358aa5c 100644
--- a/src/wallet/bip32.rs
+++ b/src/wallet/bip32.rs
@@ -18,6 +18,7 @@
 
 use std::default::Default;
 use std::io::extensions::{u64_to_be_bytes, u64_from_be_bytes};
+use serialize::{Decoder, Decodable, Encoder, Encodable};
 
 use crypto::digest::Digest;
 use crypto::hmac::Hmac;
@@ -84,7 +85,7 @@ pub struct ExtendedPubKey {
 }
 
 /// A child number for a derived key
-#[deriving(Clone, PartialEq, Eq, Encodable, Decodable, Show)]
+#[deriving(Clone, PartialEq, Eq, Show)]
 pub enum ChildNumber {
   /// Hardened key index, within [0, 2^31 - 1]
   Hardened(u32),
@@ -92,6 +93,26 @@ pub enum ChildNumber {
   Normal(u32),
 }
 
+impl<S: Encoder<E>, E> Encodable<S, E> for ChildNumber {
+  fn encode(&self, s: &mut S) -> Result<(), E> {
+    match *self {
+      Hardened(n) => (n + (1 << 31)).encode(s),
+      Normal(n)   => n.encode(s)
+    }
+  }
+}
+
+impl<D: Decoder<E>, E> Decodable<D, E> for ChildNumber {
+  fn decode(d: &mut D) -> Result<ChildNumber, E> { 
+    let n: u32 = try!(Decodable::decode(d));
+    if n < (1 << 31) {
+      Ok(Normal(n))
+    } else {
+      Ok(Hardened(n - (1 << 31)))
+    }
+  }
+}
+
 /// A BIP32 error
 #[deriving(Clone, PartialEq, Eq, Show)]
 pub enum Error {
@@ -476,6 +497,25 @@ mod tests {
               "xpub6FnCn6nSzZAw5Tw7cgR9bi15UV96gLZhjDstkXXxvCLsUXBGXPdSnLFbdpq8p9HmGsApME5hQTZ3emM2rnY5agb9rXpVGyy3bdW6EEgAtqt");
   }
 
+  #[test]
+  pub fn encode_decode_childnumber() {
+    use serialize::json;
+
+    let h1 = Hardened(1);
+    let n1 = Normal(1);
+
+    let h1_str = json::encode(&h1);
+    let n1_str = json::encode(&n1);
+
+    assert!(h1 != n1);
+    assert!(h1_str != n1_str);
+
+    let h1_dec = json::decode(h1_str.as_slice()).unwrap();
+    let n1_dec = json::decode(n1_str.as_slice()).unwrap();
+    assert_eq!(h1, h1_dec);
+    assert_eq!(n1, n1_dec);
+  }
+
   #[bench]
   pub fn generate_sequential_normal_children(bh: &mut Bencher) {
     let seed = "000102030405060708090a0b0c0d0e0f".from_hex().unwrap();
diff --git a/src/wallet/wallet.rs b/src/wallet/wallet.rs
index 70f95d8..4eec4c9 100644
--- a/src/wallet/wallet.rs
+++ b/src/wallet/wallet.rs
@@ -30,6 +30,7 @@ use wallet::bip32::{mod, ChildNumber, ExtendedPrivKey, Normal, Hardened};
 use wallet::address::Address;
 
 /// A Wallet error
+#[deriving(Clone, PartialEq, Eq, Show)]
 pub enum Error {
   /// Tried to lookup an account by name, but none was found
   AccountNotFound,
@@ -97,9 +98,6 @@ impl<S: Encoder<E>, E> Encodable<S, E> for Wallet {
   }
 }
 
-impl Account {
-}
-
 impl<D: Decoder<E>, E> Decodable<D, E> for Wallet {
   fn decode(d: &mut D) -> Result<Wallet, E> { 
     d.read_struct("wallet", 2, |d| {