Some extra comments

src/keystore.h

@@ -7,21 +7,34 @@
 
 #include "crypter.h"
 
+// A virtual base class for key stores
 class CKeyStore
 {
 protected:
     mutable CCriticalSection cs_KeyStore;
 
 public:
+    // Add a key to the store.
     virtual bool AddKey(const CKey& key) =0;
+
+    // Check whether a key corresponding to a given address is present in the store.
     virtual bool HaveKey(const CBitcoinAddress &address) const =0;
+
+    // Retrieve a key corresponding to a given address from the store.
+    // Return true if succesful.
     virtual bool GetKey(const CBitcoinAddress &address, CKey& keyOut) const =0;
+
+    // Retrieve only the public key corresponding to a given address.
+    // This may succeed even if GetKey fails (e.g., encrypted wallets)
     virtual bool GetPubKey(const CBitcoinAddress &address, std::vector<unsigned char>& vchPubKeyOut) const;
+
+    // Generate a new key, and add it to the store
     virtual std::vector<unsigned char> GenerateNewKey();
 };
 
 typedef std::map<CBitcoinAddress, CSecret> KeyMap;
 
+// Basic key store, that keeps keys in an address->secret map
 class CBasicKeyStore : public CKeyStore
 {
 protected:
@@ -53,6 +66,8 @@ public:
 
 typedef std::map<CBitcoinAddress, std::pair<std::vector<unsigned char>, std::vector<unsigned char> > > CryptedKeyMap;
 
+// Keystore which keeps the private keys encrypted
+// It derives from the basic key store, which is used if no encryption is active.
 class CCryptoKeyStore : public CBasicKeyStore
 {
 private: