diff --git a/alethzero/MainWin.cpp b/alethzero/MainWin.cpp
index 865cfec3e..ec58fd559 100644
--- a/alethzero/MainWin.cpp
+++ b/alethzero/MainWin.cpp
@@ -1733,7 +1733,7 @@ void Main::on_data_textChanged()
 //				compiler.addSources(dev::solidity::StandardSources);
 				m_data = compiler.compile(src, m_enableOptimizer);
 				solidity = "<h4>Solidity</h4>";
-				solidity += "<pre>var " + QString::fromStdString(compiler.getContractNames().front()) + " = web3.eth.contractFromAbi(" + QString::fromStdString(compiler.getInterface()).replace(QRegExp("\\s"), "").toHtmlEscaped() + ");</pre>";
+				solidity += "<pre>var " + QString::fromStdString(compiler.defaultContractName()) + " = web3.eth.contractFromAbi(" + QString::fromStdString(compiler.getInterface()).replace(QRegExp("\\s"), "").toHtmlEscaped() + ");</pre>";
 				solidity += "<pre>" + QString::fromStdString(compiler.getSolidityInterface()).toHtmlEscaped() + "</pre>";
 				solidity += "<pre>" + QString::fromStdString(getFunctionHashes(compiler)).toHtmlEscaped() + "</pre>";
 			}
@@ -2442,6 +2442,18 @@ string Main::lookupNatSpecUserNotice(dev::h256 const& _contractHash, dev::bytes
 	return m_natspecDB.getUserNotice(_contractHash, _transactionData);
 }
 
+int Main::authenticate(QString _title, QString _text)
+{
+	QMessageBox userInput(this);
+	userInput.setText(_title);
+	userInput.setInformativeText(_text);
+	userInput.setStandardButtons(QMessageBox::Ok | QMessageBox::Cancel);
+	userInput.button(QMessageBox::Ok)->setText("Allow");
+	userInput.button(QMessageBox::Cancel)->setText("Reject");
+	userInput.setDefaultButton(QMessageBox::Cancel);
+	return userInput.exec();
+}
+
 void Main::refreshWhispers()
 {
 	ui->whispers->clear();
diff --git a/alethzero/MainWin.h b/alethzero/MainWin.h
index 5298a28a2..fa451b63f 100644
--- a/alethzero/MainWin.h
+++ b/alethzero/MainWin.h
@@ -79,6 +79,12 @@ public:
 	
 	QVariant evalRaw(QString const& _js);
 
+	QString pretty(dev::Address _a) const override;
+	QString prettyU256(dev::u256 _n) const override;
+	QString render(dev::Address _a) const override;
+	dev::Address fromString(QString const& _a) const override;
+	std::string renderDiff(dev::eth::StateDiff const& _d) const override;
+
 public slots:
 	void load(QString _file);
 	void note(QString _entry);
@@ -86,6 +92,8 @@ public slots:
 	void warn(QString _entry);
 	QString contents(QString _file);
 
+	int authenticate(QString _title, QString _text);
+
 	void onKeysChanged();
 
 private slots:
@@ -175,12 +183,6 @@ private:
 	void updateDebugger();
 	void debugFinished();
 
-	QString pretty(dev::Address _a) const override;
-	QString prettyU256(dev::u256 _n) const override;
-	QString render(dev::Address _a) const override;
-	dev::Address fromString(QString const& _a) const override;
-	std::string renderDiff(dev::eth::StateDiff const& _d) const override;
-
 	void alterDebugStateGroup(bool _enable) const;
 
 	void updateFee();
diff --git a/alethzero/OurWebThreeStubServer.cpp b/alethzero/OurWebThreeStubServer.cpp
index 02d7236df..89d616756 100644
--- a/alethzero/OurWebThreeStubServer.cpp
+++ b/alethzero/OurWebThreeStubServer.cpp
@@ -46,48 +46,72 @@ string OurWebThreeStubServer::shh_newIdentity()
 
 bool OurWebThreeStubServer::showAuthenticationPopup(string const& _title, string const& _text) const
 {
-	QMessageBox userInput;
-	userInput.setText(QString::fromStdString(_title));
-	userInput.setInformativeText(QString::fromStdString(_text + "\n Do you wish to allow this?"));
-	userInput.setStandardButtons(QMessageBox::Ok | QMessageBox::Cancel);
-	userInput.button(QMessageBox::Ok)->setText("Allow");
-	userInput.button(QMessageBox::Cancel)->setText("Reject");
-	userInput.setDefaultButton(QMessageBox::Cancel);
-	return userInput.exec() == QMessageBox::Ok;
+	int button;
+	QMetaObject::invokeMethod(m_main, "authenticate", Qt::BlockingQueuedConnection, Q_RETURN_ARG(int, button), Q_ARG(QString, QString::fromStdString(_title)), Q_ARG(QString, QString::fromStdString(_text)));
+	return button == QMessageBox::Ok;
 }
 
-void OurWebThreeStubServer::showBasicValueTransferNotice(u256 _value) const
+bool OurWebThreeStubServer::showCreationNotice(TransactionSkeleton const& _t) const
 {
-	QMessageBox notice;
-	notice.setText("Basic Value Transfer Transaction");
-	notice.setInformativeText(QString::fromStdString("Value is " + toString(_value)));
-	notice.setStandardButtons(QMessageBox::Ok);
-	notice.exec();
+	return showAuthenticationPopup("Contract Creation Transaction", "ÐApp is attemping to create a contract; to be endowed with " + formatBalance(_t.value) + ", with additional network fees of up to " + formatBalance(_t.gas * _t.gasPrice) + ".\n\nMaximum total cost is <b>" + formatBalance(_t.value + _t.gas * _t.gasPrice) + "</b>.");
+}
+
+bool OurWebThreeStubServer::showSendNotice(TransactionSkeleton const& _t) const
+{
+	return showAuthenticationPopup("Fund Transfer Transaction", "ÐApp is attempting to send " + formatBalance(_t.value) + " to a recipient " + m_main->pretty(_t.to).toStdString() + ", with additional network fees of up to " + formatBalance(_t.gas * _t.gasPrice) + ".\n\nMaximum total cost is <b>" + formatBalance(_t.value + _t.gas * _t.gasPrice) + "</b>.");
+}
+
+bool OurWebThreeStubServer::showUnknownCallNotice(TransactionSkeleton const& _t) const
+{
+	return showAuthenticationPopup("DANGEROUS! Unknown Contract Transaction!",
+		"ÐApp is attempting to call into an unknown contract at address " +
+		m_main->pretty(_t.to).toStdString() +
+		".\n\nCall involves sending " +
+		formatBalance(_t.value) + " to the recipient, with additional network fees of up to " +
+		formatBalance(_t.gas * _t.gasPrice) +
+		"However, this also does other stuff which we don't understand, and does so in your name.\n\n" +
+		"WARNING: This is probably going to cost you at least " +
+		formatBalance(_t.value + _t.gas * _t.gasPrice) +
+		", however this doesn't include any side-effects, which could be of far greater importance.\n\n" +
+		"REJECT UNLESS YOU REALLY KNOW WHAT YOU ARE DOING!");
 }
 
 bool OurWebThreeStubServer::authenticate(TransactionSkeleton const& _t)
 {
+	if (_t.creation)
+	{
+		// recipient has no code - nothing special about this transaction, show basic value transfer info
+		return showCreationNotice(_t);
+	}
+
 	h256 contractCodeHash = m_web3->ethereum()->postState().codeHash(_t.to);
 	if (contractCodeHash == EmptySHA3)
-		// contract creation
-		return true;
-
-	if (false) //TODO: When is is just a value transfer?
 	{
 		// recipient has no code - nothing special about this transaction, show basic value transfer info
-		showBasicValueTransferNotice(_t.value);
-		return true;
+		return showSendNotice(_t);
 	}
 
+	// TODO: include total cost in Ether
 	string userNotice = m_main->lookupNatSpecUserNotice(contractCodeHash, _t.data);
 
 	if (userNotice.empty())
-		return showAuthenticationPopup("Unverified Pending Transaction",
-									   "An undocumented transaction is about to be executed.");
+		return showUnknownCallNotice(_t);
 
 	NatspecExpressionEvaluator evaluator;
 	userNotice = evaluator.evalExpression(QString::fromStdString(userNotice)).toStdString();
 
 	// otherwise it's a transaction to a contract for which we have the natspec
-	return showAuthenticationPopup("Pending Transaction", userNotice);
+	return showAuthenticationPopup("Contract Transaction",
+		"ÐApp attempting to conduct contract interaction with " +
+		m_main->pretty(_t.to).toStdString() +
+		": <b>" + userNotice + "</b>.\n\n" +
+		(_t.value > 0 ?
+			"In addition, ÐApp is attempting to send " +
+			formatBalance(_t.value) + " to said recipient, with additional network fees of up to " +
+			formatBalance(_t.gas * _t.gasPrice) + " = <b>" +
+			formatBalance(_t.value + _t.gas * _t.gasPrice) + "</b>."
+		:
+			"Additional network fees are at most" +
+			formatBalance(_t.gas * _t.gasPrice) + ".")
+		);
 }
diff --git a/alethzero/OurWebThreeStubServer.h b/alethzero/OurWebThreeStubServer.h
index 303b73111..fbdae7d03 100644
--- a/alethzero/OurWebThreeStubServer.h
+++ b/alethzero/OurWebThreeStubServer.h
@@ -42,7 +42,9 @@ signals:
 
 private:
 	bool showAuthenticationPopup(std::string const& _title, std::string const& _text) const;
-	void showBasicValueTransferNotice(dev::u256 _value) const;
+	bool showCreationNotice(dev::eth::TransactionSkeleton const& _t) const;
+	bool showSendNotice(dev::eth::TransactionSkeleton const& _t) const;
+	bool showUnknownCallNotice(dev::eth::TransactionSkeleton const& _t) const;
 
 	dev::WebThreeDirect* m_web3;
 	Main* m_main;
diff --git a/libethcore/CommonJS.h b/libethcore/CommonJS.h
index 2f82d8945..abe74f0af 100644
--- a/libethcore/CommonJS.h
+++ b/libethcore/CommonJS.h
@@ -144,6 +144,7 @@ inline Address jsToAddress(std::string const& _s) { return jsToFixed<sizeof(dev:
 
 struct TransactionSkeleton
 {
+	bool creation = false;
 	Address from;
 	Address to;
 	u256 value;
diff --git a/libsolidity/CompilerStack.cpp b/libsolidity/CompilerStack.cpp
index 762edb521..ca9c75bcd 100644
--- a/libsolidity/CompilerStack.cpp
+++ b/libsolidity/CompilerStack.cpp
@@ -333,6 +333,11 @@ void CompilerStack::resolveImports()
 	swap(m_sourceOrder, sourceOrder);
 }
 
+std::string CompilerStack::defaultContractName() const
+{
+	return getContract("").contract->getName();
+}
+
 CompilerStack::Contract const& CompilerStack::getContract(string const& _contractName) const
 {
 	if (m_contracts.empty())
diff --git a/libsolidity/CompilerStack.h b/libsolidity/CompilerStack.h
index 439077f36..cb4770cd3 100644
--- a/libsolidity/CompilerStack.h
+++ b/libsolidity/CompilerStack.h
@@ -73,6 +73,7 @@ public:
 	void parse(std::string const& _sourceCode);
 	/// Returns a list of the contract names in the sources.
 	std::vector<std::string> getContractNames() const;
+	std::string defaultContractName() const;
 
 	/// Compiles the source units that were previously added and parsed.
 	void compile(bool _optimize = false);
diff --git a/libweb3jsonrpc/WebThreeStubServerBase.cpp b/libweb3jsonrpc/WebThreeStubServerBase.cpp
index 49094a423..27b8268da 100644
--- a/libweb3jsonrpc/WebThreeStubServerBase.cpp
+++ b/libweb3jsonrpc/WebThreeStubServerBase.cpp
@@ -279,6 +279,8 @@ static TransactionSkeleton toTransaction(Json::Value const& _json)
 		ret.from = jsToAddress(_json["from"].asString());
 	if (_json["to"].isString())
 		ret.to = jsToAddress(_json["to"].asString());
+	else
+		ret.creation = true;
 	if (!_json["value"].empty())
 	{
 		if (_json["value"].isString())