diff --git a/src/allocators.h b/src/allocators.h
index b4490ce2..85af8fe3 100644
--- a/src/allocators.h
+++ b/src/allocators.h
@@ -176,6 +176,10 @@ private:
     {}
 };
 
+//
+// Functions for directly locking/unlocking memory objects.
+// Intended for non-dynamically allocated structures.
+//
 template<typename T> void LockObject(const T &t) {
     LockedPageManager::instance.LockRange((void*)(&t), sizeof(T));
 }
diff --git a/src/key.h b/src/key.h
index b9ecd485..ce469ad2 100644
--- a/src/key.h
+++ b/src/key.h
@@ -84,7 +84,7 @@ public:
         Set(vch.begin(), vch.end());
     }
 
-    // Simply read-only vector-like interface to the pubkey data.
+    // Simple read-only vector-like interface to the pubkey data.
     unsigned int size() const { return GetLen(vch[0]); }
     const unsigned char *begin() const { return vch; }
     const unsigned char *end() const { return vch+size(); }
@@ -109,12 +109,11 @@ public:
     }
     template<typename Stream> void Serialize(Stream &s, int nType, int nVersion) const {
         unsigned int len = size();
-        ::Serialize(s, VARINT(len), nType, nVersion);
+        ::WriteCompactSize(s, len);
         s.write((char*)vch, len);
     }
     template<typename Stream> void Unserialize(Stream &s, int nType, int nVersion) {
-        unsigned int len;
-        ::Unserialize(s, VARINT(len), nType, nVersion);
+        unsigned int len = ::ReadCompactSize(s);
         if (len <= 65) {
             s.read((char*)vch, len);
         } else {
diff --git a/src/script.cpp b/src/script.cpp
index 2c7fd598..b4116663 100644
--- a/src/script.cpp
+++ b/src/script.cpp
@@ -16,7 +16,7 @@ using namespace boost;
 #include "sync.h"
 #include "util.h"
 
-bool CheckSig(vector<unsigned char> vchSig, vector<unsigned char> vchPubKey, CScript scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType, int flags);
+bool CheckSig(vector<unsigned char> vchSig, const vector<unsigned char> &vchPubKey, const CScript &scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType, int flags);
 
 
 
@@ -1033,13 +1033,13 @@ class CSignatureCache
 {
 private:
      // sigdata_type is (signature hash, signature, public key):
-    typedef boost::tuple<uint256, std::vector<unsigned char>, std::vector<unsigned char> > sigdata_type;
+    typedef boost::tuple<uint256, std::vector<unsigned char>, CPubKey> sigdata_type;
     std::set< sigdata_type> setValid;
     boost::shared_mutex cs_sigcache;
 
 public:
     bool
-    Get(uint256 hash, const std::vector<unsigned char>& vchSig, const std::vector<unsigned char>& pubKey)
+    Get(const uint256 &hash, const std::vector<unsigned char>& vchSig, const CPubKey& pubKey)
     {
         boost::shared_lock<boost::shared_mutex> lock(cs_sigcache);
 
@@ -1050,7 +1050,7 @@ public:
         return false;
     }
 
-    void Set(uint256 hash, const std::vector<unsigned char>& vchSig, const std::vector<unsigned char>& pubKey)
+    void Set(const uint256 &hash, const std::vector<unsigned char>& vchSig, const CPubKey& pubKey)
     {
         // DoS prevention: limit cache size to less than 10MB
         // (~200 bytes per cache entry times 50,000 entries)
@@ -1081,11 +1081,15 @@ public:
     }
 };
 
-bool CheckSig(vector<unsigned char> vchSig, vector<unsigned char> vchPubKey, CScript scriptCode,
+bool CheckSig(vector<unsigned char> vchSig, const vector<unsigned char> &vchPubKey, const CScript &scriptCode,
               const CTransaction& txTo, unsigned int nIn, int nHashType, int flags)
 {
     static CSignatureCache signatureCache;
 
+    CPubKey pubkey(vchPubKey);
+    if (!pubkey.IsValid())
+        return false;
+
     // Hash type is one byte tacked on to the end of the signature
     if (vchSig.empty())
         return false;
@@ -1097,14 +1101,14 @@ bool CheckSig(vector<unsigned char> vchSig, vector<unsigned char> vchPubKey, CSc
 
     uint256 sighash = SignatureHash(scriptCode, txTo, nIn, nHashType);
 
-    if (signatureCache.Get(sighash, vchSig, vchPubKey))
+    if (signatureCache.Get(sighash, vchSig, pubkey))
         return true;
 
-    if (!CPubKey(vchPubKey).Verify(sighash, vchSig))
+    if (!pubkey.Verify(sighash, vchSig))
         return false;
 
     if (!(flags & SCRIPT_VERIFY_NOCACHE))
-        signatureCache.Set(sighash, vchSig, vchPubKey);
+        signatureCache.Set(sighash, vchSig, pubkey);
 
     return true;
 }