diff --git a/src/blockdata/transaction.rs b/src/blockdata/transaction.rs
index 1202e02..e158290 100644
--- a/src/blockdata/transaction.rs
+++ b/src/blockdata/transaction.rs
@@ -34,7 +34,7 @@ use network::encodable::ConsensusEncodable;
 use network::serialize::BitcoinHash;
 
 /// A transaction input, which defines old coins to be consumed
-#[deriving(Clone, PartialEq, Show)]
+#[deriving(Clone, PartialEq, Eq, Show)]
 pub struct TxIn {
   /// The hash of the transaction whose output is being used an an input
   pub prev_hash: Sha256dHash,
@@ -51,7 +51,7 @@ pub struct TxIn {
 }
 
 /// A transaction output, which defines new coins to be created from old ones.
-#[deriving(Clone, PartialEq, Show)]
+#[deriving(Clone, PartialEq, Eq, Show)]
 pub struct TxOut {
   /// The value of the output, in satoshis
   pub value: u64,
@@ -67,7 +67,7 @@ impl Default for TxOut {
 }
 
 /// A Bitcoin transaction, which describes an authenticated movement of coins
-#[deriving(Clone, PartialEq, Show)]
+#[deriving(Clone, PartialEq, Eq, Show)]
 pub struct Transaction {
   /// The protocol version, should always be 1.
   pub version: u32,
diff --git a/src/internal_macros.rs b/src/internal_macros.rs
index 2a0afda..66cfa6f 100644
--- a/src/internal_macros.rs
+++ b/src/internal_macros.rs
@@ -36,6 +36,25 @@ macro_rules! impl_consensus_encoding(
   );
 )
 
+macro_rules! impl_newtype_consensus_encoding(
+  ($thing:ident) => (
+    impl<S: ::network::serialize::SimpleEncoder<E>, E> ::network::encodable::ConsensusEncodable<S, E> for $thing {
+      #[inline]
+      fn consensus_encode(&self, s: &mut S) -> Result<(), E> {
+        let &$thing(ref data) = self;
+        data.consensus_encode(s)
+      }
+    }
+
+    impl<D: ::network::serialize::SimpleDecoder<E>, E> ::network::encodable::ConsensusDecodable<D, E> for $thing {
+      #[inline]
+      fn consensus_decode(d: &mut D) -> Result<$thing, E> {
+        Ok($thing(try!(ConsensusDecodable::consensus_decode(d))))
+      }
+    }
+  );
+)
+
 macro_rules! impl_json(
   ($thing:ident, $($field:ident),+) => (
     impl ::serialize::json::ToJson for $thing {
diff --git a/src/network/encodable.rs b/src/network/encodable.rs
index 965a736..e9eb54e 100644
--- a/src/network/encodable.rs
+++ b/src/network/encodable.rs
@@ -319,23 +319,33 @@ impl<D:SimpleDecoder<E>, E> ConsensusDecodable<D, E> for CheckedData {
 }
 
 // Tuples
-impl<S:SimpleEncoder<E>, E, T: ConsensusEncodable<S, E>, U: ConsensusEncodable<S, E>> ConsensusEncodable<S, E> for (T, U) {
-  #[inline]
-  fn consensus_encode(&self, s: &mut S) -> Result<(), E> {
-    let &(ref s1, ref s2) = self;
-    try!(s1.consensus_encode(s));
-    try!(s2.consensus_encode(s));
-    Ok(())
-  }
-}
+macro_rules! tuple_encode(
+  ($($x:ident),*) => (
+    impl <SS:SimpleEncoder<EE>, EE, $($x: ConsensusEncodable<SS, EE>),*> ConsensusEncodable<SS, EE> for ($($x),*) {
+      #[inline]
+      #[allow(uppercase_variables)]
+      fn consensus_encode(&self, s: &mut SS) -> Result<(), EE> {
+        let &($(ref $x),*) = self;
+        $( try!($x.consensus_encode(s)); )*
+        Ok(())
+      }
+    }
+
+    impl<DD:SimpleDecoder<EE>, EE, $($x: ConsensusDecodable<DD, EE>),*> ConsensusDecodable<DD, EE> for ($($x),*) {
+      #[inline]
+      #[allow(uppercase_variables)]
+      fn consensus_decode(d: &mut DD) -> Result<($($x),*), EE> {
+        Ok(($(try!({let $x = ConsensusDecodable::consensus_decode(d); $x })),*))
+      }
+    }
+  );
+)
+
+tuple_encode!(A, B)
+tuple_encode!(A, B, C, D)
+tuple_encode!(A, B, C, D, E, F)
+tuple_encode!(A, B, C, D, E, F, G, H)
 
-impl<D:SimpleDecoder<E>, E, T: ConsensusDecodable<D, E>, U: ConsensusDecodable<D, E>> ConsensusDecodable<D, E> for (T, U) {
-  #[inline]
-  fn consensus_decode(d: &mut D) -> Result<(T, U), E> {
-    Ok((try!(ConsensusDecodable::consensus_decode(d)),
-        try!(ConsensusDecodable::consensus_decode(d))))
-  }
-}
 
 // References
 impl<S:SimpleEncoder<E>, E, T: ConsensusEncodable<S, E>> ConsensusEncodable<S, E> for Box<T> {
diff --git a/src/util/hash.rs b/src/util/hash.rs
index 6d151c2..4b26753 100644
--- a/src/util/hash.rs
+++ b/src/util/hash.rs
@@ -28,7 +28,7 @@ use crypto::digest::Digest;
 use crypto::sha2;
 
 use network::encodable::{ConsensusDecodable, ConsensusEncodable};
-use network::serialize::{RawEncoder, BitcoinHash, SimpleDecoder, SimpleEncoder};
+use network::serialize::{RawEncoder, BitcoinHash, SimpleDecoder};
 use util::uint::Uint128;
 use util::uint::Uint256;
 
@@ -44,6 +44,19 @@ pub struct Ripemd160Hash([u8, ..20]);
 /// A "hasher" which just truncates
 pub struct DumbHasher;
 
+/// A 32-bit hash obtained by truncating a real hash
+#[deriving(Clone, PartialEq, Eq, Show)]
+pub struct Hash32((u8, u8, u8, u8));
+
+/// A 48-bit hash obtained by truncating a real hash
+#[deriving(Clone, PartialEq, Eq, Show)]
+pub struct Hash48((u8, u8, u8, u8, u8, u8));
+
+/// A 64-bit hash obtained by truncating a real hash
+#[deriving(Clone, PartialEq, Eq, Show)]
+pub struct Hash64((u8, u8, u8, u8, u8, u8, u8, u8));
+
+
 // Allow these to be used as a key for Rust's HashMap et. al.
 impl hash::Hash<u64> for Sha256dHash {
   #[inline]
@@ -72,6 +85,32 @@ impl hash::Hash<u64> for Uint128 {
   }
 }
 
+impl hash::Hash<u64> for Hash32 {
+  #[inline]
+  fn hash(&self, state: &mut u64) {
+    let &Hash32((a, b, c, d)) = self;
+    *state = a as u64 + (b as u64 << 8) + (c as u64 << 16) + (d as u64 << 24);
+  }
+}
+
+impl hash::Hash<u64> for Hash48 {
+  #[inline]
+  fn hash(&self, state: &mut u64) {
+    let &Hash48((a, b, c, d, e, f)) = self;
+    *state = a as u64 + (b as u64 << 8) + (c as u64 << 16) + (d as u64 << 24) +
+             (e as u64 << 32) + (f as u64 << 40);
+  }
+}
+
+impl hash::Hash<u64> for Hash64 {
+  #[inline]
+  fn hash(&self, state: &mut u64) {
+    let &Hash64((a, b, c, d, e, f, g, h)) = self;
+    *state = a as u64 + (b as u64 << 8) + (c as u64 << 16) + (d as u64 << 24) +
+             (e as u64 << 32) + (f as u64 << 40) + (g as u64 << 48) + (h as u64 << 56);
+  }
+}
+
 impl hash::Hasher<u64> for DumbHasher {
   #[inline]
   fn hash<T: hash::Hash<u64>>(&self, value: &T) -> u64 {
@@ -122,6 +161,30 @@ impl Sha256dHash {
                                 data[31]])) }
   }
 
+  /// Converts a hash to a Hash32 by truncation
+  #[inline]
+  pub fn into_hash32(self) -> Hash32 {
+    let Sha256dHash(data) = self;
+    unsafe { transmute([data[0], data[8], data[16], data[24]]) }
+  }
+
+  /// Converts a hash to a Hash48 by truncation
+  #[inline]
+  pub fn into_hash48(self) -> Hash48 {
+    let Sha256dHash(data) = self;
+    unsafe { transmute([data[0], data[6], data[12], data[18], data[24], data[30]]) }
+  }
+
+  /// Human-readable hex output
+
+  /// Converts a hash to a Hash64 by truncation
+  #[inline]
+  pub fn into_hash64(self) -> Hash64 {
+    let Sha256dHash(data) = self;
+    unsafe { transmute([data[0], data[4], data[8], data[12],
+                        data[16], data[20], data[24], data[28]]) }
+  }
+
   /// Human-readable hex output
   pub fn le_hex_string(&self) -> String {
     let &Sha256dHash(data) = self;
@@ -214,19 +277,10 @@ impl<D: ::serialize::Decoder<E>, E> ::serialize::Decodable<D, E> for Sha256dHash
 }
 
 // Consensus encoding (little-endian)
-impl<S:SimpleEncoder<E>, E> ConsensusEncodable<S, E> for Sha256dHash {
-  #[inline]
-  fn consensus_encode(&self, s: &mut S) -> Result<(), E> {
-    self.into_uint256().consensus_encode(s)
-  }
-}
-
-impl<D:SimpleDecoder<E>, E> ConsensusDecodable<D, E> for Sha256dHash {
-  #[inline]
-  fn consensus_decode(d: &mut D) -> Result<Sha256dHash, E> {
-    Ok(Sha256dHash(try!(ConsensusDecodable::consensus_decode(d))))
-  }
-}
+impl_newtype_consensus_encoding!(Hash32)
+impl_newtype_consensus_encoding!(Hash48)
+impl_newtype_consensus_encoding!(Hash64)
+impl_newtype_consensus_encoding!(Sha256dHash)
 
 impl fmt::LowerHex for Sha256dHash {
   fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {