diff --git a/gui/src/GenerateWindow.cpp b/gui/src/GenerateWindow.cpp
index 8880ffb..fa8711c 100644
--- a/gui/src/GenerateWindow.cpp
+++ b/gui/src/GenerateWindow.cpp
@@ -92,14 +92,16 @@ m_btn_copy_both	("Copy keys")
 
 void GenerateWindow::generate_key()
 {
-	std::string pubstr;
+	std::string pubstr, pvtstr;
 	struct libeosio::ec_keypair pair;
+	const libeosio::wif_codec_t& codec = Settings::getKeyCodec();
 
 	libeosio::ec_generate_key(&pair);
 
-	pubstr = libeosio::wif_pub_encode(pair.pub, Settings::shouldGenerateFioKeys() ? "FIO" : "EOS");
+	pubstr = libeosio::wif_pub_encode(pair.pub, codec.pub);
+	pvtstr = libeosio::wif_priv_encode(pair.secret, codec.pvt);
 	m_pub.setText(QString::fromStdString(pubstr));
-	m_priv.setText(QString::fromStdString(libeosio::wif_priv_encode(pair.secret)));
+	m_priv.setText(QString::fromStdString(pvtstr));
 }
 
 void GenerateWindow::copy_both_keys()
diff --git a/gui/src/MainWindow.cpp b/gui/src/MainWindow.cpp
index 78b3a7a..4001ef4 100644
--- a/gui/src/MainWindow.cpp
+++ b/gui/src/MainWindow.cpp
@@ -25,6 +25,7 @@
 #include <QMenuBar>
 #include <QGridLayout>
 #include <QStackedWidget>
+#include <libeosio/WIF.hpp>
 #include "gui_text.h"
 #include "Settings.hpp"
 #include "GenerateWindow.hpp"
@@ -32,8 +33,10 @@
 #include "MainWindow.hpp"
 
 MainWindow::MainWindow(QWidget *parent) :
-QMainWindow	(parent),
-m_fio_action (nullptr)
+QMainWindow		(parent),
+m_format_fio_action 	(nullptr),
+m_format_legacy_action 	(nullptr),
+m_format_k1_action	(nullptr)
 {
 	libeosio::ec_init();
 
@@ -51,12 +54,28 @@ m_fio_action (nullptr)
 
 	// Settings
 
-	m_fio_action = new QAction("FIO Keys", this);
-	m_fio_action->setCheckable(true);
-	connect(m_fio_action, SIGNAL(triggered()), this, SLOT(fioKeysCheckboxChanged()));
+	QActionGroup* formatGroup = new QActionGroup(this);
 
-	QMenu *settings_menu = menuBar()->addMenu("Settings");
-	settings_menu->addAction(m_fio_action);
+	m_format_fio_action = new QAction("FIO", formatGroup);
+	m_format_fio_action->setCheckable(true);
+	m_format_legacy_action = new QAction("Legacy", formatGroup);
+	m_format_legacy_action->setCheckable(true);
+	m_format_k1_action = new QAction("K1", formatGroup);
+	m_format_k1_action->setCheckable(true);
+
+	// Set k1 and trigger the changed action so we set the codec.
+	m_format_k1_action->setChecked(true);
+	formatK1CheckboxChanged();
+
+	connect(m_format_fio_action, SIGNAL(triggered()), this, SLOT(formatFioCheckboxChanged()));
+	connect(m_format_legacy_action, SIGNAL(triggered()), this, SLOT(formatLegacyCheckboxChanged()));
+	connect(m_format_k1_action, SIGNAL(triggered()), this, SLOT(formatK1CheckboxChanged()));
+
+	QMenu *settings = menuBar()->addMenu("Settings");
+	QMenu *format_menu = settings->addMenu("Key Format");
+	format_menu->addAction(m_format_k1_action);
+	format_menu->addAction(m_format_legacy_action);
+	format_menu->addAction(m_format_fio_action);
 
 	// About
 	menuBar()->addAction("About", this, SLOT(showAbout()));
@@ -84,7 +103,23 @@ void MainWindow::showAbout()
 		EOSIOKEYGEN_GUI_TEXT_ABOUT_BODY);
 }
 
-void MainWindow::fioKeysCheckboxChanged()
+void MainWindow::formatFioCheckboxChanged()
 {
-	Settings::setGenerateFioKeys(m_fio_action ? m_fio_action->isChecked() : false);
+	if (m_format_fio_action->isChecked()) {
+		Settings::setKeyCodec(libeosio::wif_create_legacy_codec("FIO"));
+	}
+}
+
+void MainWindow::formatLegacyCheckboxChanged()
+{
+	if (m_format_legacy_action->isChecked()) {
+		Settings::setKeyCodec(libeosio::WIF_CODEC_LEG);
+	}
+}
+
+void MainWindow::formatK1CheckboxChanged()
+{
+	if (m_format_k1_action->isChecked()) {
+		Settings::setKeyCodec(libeosio::WIF_CODEC_K1);
+	}
 }
diff --git a/gui/src/MainWindow.hpp b/gui/src/MainWindow.hpp
index 06d3fcb..3d4b172 100644
--- a/gui/src/MainWindow.hpp
+++ b/gui/src/MainWindow.hpp
@@ -47,13 +47,17 @@ private slots :
 
 	void showAbout();
 
-	void fioKeysCheckboxChanged();
+	void formatFioCheckboxChanged();
+	void formatLegacyCheckboxChanged();
+	void formatK1CheckboxChanged();
 
 private :
 
 	QStackedWidget* m_stacked;
 
-	QPointer<QAction> m_fio_action;
+	QPointer<QAction> m_format_fio_action;
+	QPointer<QAction> m_format_legacy_action;
+	QPointer<QAction> m_format_k1_action;
 };
 
 #endif /* MAIN_WINDOW_H */
diff --git a/gui/src/SearchWindow.cpp b/gui/src/SearchWindow.cpp
index 23e2cf3..7af886d 100644
--- a/gui/src/SearchWindow.cpp
+++ b/gui/src/SearchWindow.cpp
@@ -150,14 +150,16 @@ void SearchWindow::onResult(const struct libeosio::ec_keypair* key, const struct
 {
 	int pos = (int) result.pos;
 	int len = (int) result.len;
- 	QString pub = QString::fromStdString(libeosio::wif_pub_encode(key->pub, Settings::shouldGenerateFioKeys() ? "FIO" : "EOS"));
+	libeosio::wif_codec_t codec = Settings::getKeyCodec();
+ 	QString pub = QString::fromStdString(libeosio::wif_pub_encode(key->pub, codec.pub));
+	int pub_prefix_len = (int) codec.pub.length();
 	QString mid = pub.mid(pos, len);
 	QString left = pub.left(pos);
 	QString right = pub.mid(pos + len, pub.size() - pos);
 	eoskeygen::Dictionary::search_result_t dict_res = m_dict.search(pub.toStdString());
 
-	QString out = "Public:  " + pub.left(3);
-	for(int i = 3; i < pub.length(); ) {
+	QString out = "Public:  " + pub.left(pub_prefix_len);
+	for(int i = pub_prefix_len; i < pub.length(); ) {
 
 		if (i == pos) {
 			out += "<font color=red>" + pub.mid(pos, len) + "</font>";
@@ -178,7 +180,7 @@ void SearchWindow::onResult(const struct libeosio::ec_keypair* key, const struct
 		out += pub[i++];
 	}
 
-	out += "<br/>Private: " + QString::fromStdString(libeosio::wif_priv_encode(key->secret));
+	out += "<br/>Private: " + QString::fromStdString(libeosio::wif_priv_encode(key->secret, codec.pvt));
 
 	// As this function could be called from a non-gui thread. we use signals.
 	emit addOutput("<p>" + out + "</p>");
@@ -253,6 +255,9 @@ void SearchWindow::langFileAdd()
 
 void SearchWindow::searchStarted()
 {
+	// Set prefix for search
+	m_ksearch.setPrefix(Settings::getKeyCodec().pub);
+
 	m_btn_exec.setText("Cancel");
 
 	m_txt_search.setEnabled(false);
diff --git a/gui/src/Settings.cpp b/gui/src/Settings.cpp
index d49c408..733e028 100644
--- a/gui/src/Settings.cpp
+++ b/gui/src/Settings.cpp
@@ -24,16 +24,14 @@
 #include "Settings.hpp"
 
 namespace priv {
-	bool fio_keys = false;
 
+	libeosio::wif_codec_t key_format = libeosio::WIF_CODEC_K1;
 } // namespace priv
 
-bool Settings::shouldGenerateFioKeys()
-{
-	return priv::fio_keys;
+void Settings::setKeyCodec(const libeosio::wif_codec_t& format) {
+	priv::key_format = format;
 }
 
-void Settings::setGenerateFioKeys(bool value)
-{
-	priv::fio_keys = value;
+const libeosio::wif_codec_t& Settings::getKeyCodec() {
+	return priv::key_format;
 }
diff --git a/gui/src/Settings.hpp b/gui/src/Settings.hpp
index d47c26f..4cf04be 100644
--- a/gui/src/Settings.hpp
+++ b/gui/src/Settings.hpp
@@ -24,11 +24,13 @@
 #ifndef SETTINGS_H
 #define SETTINGS_H
 
+#include <libeosio/WIF.hpp>
+
 namespace Settings
 {
-	bool shouldGenerateFioKeys();
+	void setKeyCodec(const libeosio::wif_codec_t& format);
 
-	void setGenerateFioKeys(bool value);
+	const libeosio::wif_codec_t& getKeyCodec();
 };
 
 #endif /* SEARCH_WINDOW_H */