wallet2_api: API to sign and verify a message

src/wallet/api/wallet.cpp

@@ -752,6 +752,23 @@ std::string WalletImpl::getTxKey(const std::string &txid) const
     }
 }
 
+std::string WalletImpl::signMessage(const std::string &message)
+{
+  return m_wallet->sign(message);
+}
+
+bool WalletImpl::verifySignedMessage(const std::string &message, const std::string &address, const std::string &signature) const
+{
+  cryptonote::account_public_address addr;
+  bool has_payment_id;
+  crypto::hash8 payment_id;
+
+  if (!cryptonote::get_account_integrated_address_from_str(addr, has_payment_id, payment_id, m_wallet->testnet(), address))
+    return false;
+
+  return m_wallet->verify(message, addr, signature);
+}
+
 bool WalletImpl::connectToDaemon()
 {
     bool result = m_wallet->check_connection();

src/wallet/api/wallet.h

@@ -101,6 +101,9 @@ public:
     virtual std::string getUserNote(const std::string &txid) const;
     virtual std::string getTxKey(const std::string &txid) const;
 
+    virtual std::string signMessage(const std::string &message);
+    virtual bool verifySignedMessage(const std::string &message, const std::string &address, const std::string &signature) const;
+
 private:
     void clearStatus();
     void refreshThreadFunc();

src/wallet/wallet2_api.h

@@ -362,6 +362,21 @@ struct Wallet
      */
     virtual std::string getUserNote(const std::string &txid) const = 0;
     virtual std::string getTxKey(const std::string &txid) const = 0;
+
+    /*
+     * \brief signMessage - sign a message with the spend private key
+     * \param message - the message to sign (arbitrary byte data)
+     * \return the signature
+     */
+    virtual std::string signMessage(const std::string &message) = 0;
+    /*!
+     * \brief verifySignedMessage - verify a signature matches a given message
+     * \param message - the message (arbitrary byte data)
+     * \param address - the address the signature claims to be made with
+     * \param signature - the signature
+     * \return true if the signature verified, false otherwise
+     */
+    virtual bool verifySignedMessage(const std::string &message, const std::string &addres, const std::string &signature) const = 0;
 };
 
 /**