Add support for spending keys to the basic key store

src/zcash/Address.cpp

@@ -8,7 +8,7 @@ uint256 ViewingKey::pk_enc() {
     return ZCNoteEncryption::generate_pubkey(*this);
 }
 
-ViewingKey SpendingKey::viewing_key() {
+ViewingKey SpendingKey::viewing_key() const {
     return ViewingKey(ZCNoteEncryption::generate_privkey(*this));
 }
 
@@ -16,8 +16,8 @@ SpendingKey SpendingKey::random() {
     return SpendingKey(random_uint252());
 }
 
-PaymentAddress SpendingKey::address() {
+PaymentAddress SpendingKey::address() const {
     return PaymentAddress(PRF_addr_a_pk(*this), viewing_key().pk_enc());
 }
 
-}
+}

src/zcash/Address.hpp

@@ -22,6 +22,8 @@ public:
         READWRITE(a_pk);
         READWRITE(pk_enc);
     }
+
+    friend inline bool operator<(const PaymentAddress& a, const PaymentAddress& b) { return a.a_pk < b.a_pk; }
 };
 
 class ViewingKey : public uint256 {
@@ -38,8 +40,8 @@ public:
 
     static SpendingKey random();
 
-    ViewingKey viewing_key();
-    PaymentAddress address();
+    ViewingKey viewing_key() const;
+    PaymentAddress address() const;
 };
 
 }