diff --git a/Tweetodon/User.pm b/Tweetodon/User.pm
index 00ee5bc..d596810 100644
--- a/Tweetodon/User.pm
+++ b/Tweetodon/User.pm
@@ -8,15 +8,20 @@ use JSON;
 use Tweetodon::Token;
 use Data::Dumper;
 
-sub dbTable :lvalue { "invalid"; }
-sub orderBy :lvalue { "invalid"; }
+sub dbTable :lvalue { "users"; }
+sub orderBy :lvalue { "username"; }
 
 # Class functions
 sub authenticate {
 	my $class = shift;
 
-	my $instance = $main::FORM{instance};
-	my $token = $main::FORM{token};
+	my $session_id = $main::FORM{session_id};
+	return 0 unless defined($session_id);
+	my $user = $class->get_by("session_id", $session_id);
+	return 0 unless $user;
+
+	my $instance = $user->{data}->{instance};
+	my $token = $user->{data}->{access_token};
 	if ($token){
 		open(DATA, "./verify_credentials.bash '$token' '$instance'|");
 		my $reply;
@@ -27,11 +32,12 @@ sub authenticate {
 		close DATA;
 		$reply = decode_json($reply);
 		#{"error":"The access token is invalid"}
-		if (defined($$reply{error})){
+		if (!defined($$reply{username})){
 			return 0;
 		}
+		$reply->{token} = $token;
+		$reply->{instance} = $instance;
 		return $class->new($reply);
-		#{"id":8225,"username":"b_playsgames","acct":"b_playsgames","display_name":"Ben Plays Games","locked":false,"created_at":"2017-04-18T18:10:51.707Z","followers_count":8,"following_count":0,"statuses_count":13,"note":"Playing games for fun and reduced backlog! Join me at <a href=\\"https://yt.benplaysgames.com/\\" rel=\\"nofollow noopener\\" target=\\"_blank\\"><span class=\\"invisible\\">https://</span><span class=\\"\\">yt.benplaysgames.com/</span><span class=\\"invisible\\"></span></a>","url":"https://toot.berlin/@b_playsgames","avatar":"https://toot.berlin/system/accounts/avatars/000/008/225/original/12899445370222cb.jpg?1492540236","avatar_static":"https://toot.berlin/system/accounts/avatars/000/008/225/original/12899445370222cb.jpg?1492540236","header":"https://toot.berlin/system/accounts/headers/000/008/225/original/0e643b731c89e5a2.jpg?1492540236","header_static":"https://toot.berlin/system/accounts/headers/000/008/225/original/0e643b731c89e5a2.jpg?1492540236"}
 	}
 	return 0;
 }
diff --git a/Tweetodon/Website/Callback.pm b/Tweetodon/Website/Callback.pm
index cd33360..2ddb3e8 100644
--- a/Tweetodon/Website/Callback.pm
+++ b/Tweetodon/Website/Callback.pm
@@ -5,12 +5,14 @@ use HTML::Template;
 use Tweetodon::Website;
 use Tweetodon::App;
 use Tweetodon::Token;
-use Tweetodon::DB;
 
 package Tweetodon::Website::Callback;
 @Tweetodon::Website::Callback::ISA = qw(Tweetodon::Website);
 use Data::Dumper;
+use UUID::Tiny;
+use Digest::SHA qw(sha256_base64);
 use JSON;
+use Tweetodon::DB;
 
 sub requires_authentication {
 	return 0;
@@ -27,7 +29,6 @@ sub prerender {
 	$self->{"params"}->{"currentmode"} = "Callback";
 
 	my $instance = $main::FORM{instance};
-
 	my $app = Tweetodon::App->get_or_create_by_instance($instance);
 
 	open(DATA, "./process_code.bash '$app->{data}->{instance_client_id}' '$app->{data}->{instance_client_secret}' '$main::FORM{code}' '$main::config->{app}->{redirect_uris}' '$instance'|");
@@ -38,10 +39,29 @@ sub prerender {
 	}
 	close DATA;
 	$reply = decode_json($reply);
+	if (!defined($$reply{access_token})){
+		main::Error("Login error", "There was an error logging you in!");
+		return 0;
+	}
 
-	$self->{"set_cookie"} = ("token=".$reply->{access_token});
-	# Tweetodon::DB->doINSERT("INSERT INTO tokens (access_token, token_type, scope, created_at, username) VALUES (?, ?, ?, ?, ?)", $reply->{access_token}, $reply->{token_type}, $reply->{scope}, $reply->{created_at}, $main::FORM{Username});
-	#{"access_token":"9615e561d0cf3cb54799ecc381f10b059e781dac2b180e708dcd66683c1cdb81","token_type":"bearer","scope":"read write","created_at":1492718172}
+	my $token = $$reply{access_token};
+	open(DATA, "./verify_credentials.bash '$token' '$instance'|");
+	{
+		$/ = undef;
+		$reply = <DATA>
+	}
+	close DATA;
+	$reply = decode_json($reply);
+	if (!defined($$reply{acct})){
+		main::Error("Login error", "There was an error logging you in!");
+		return 0;
+	}
+
+	my $session_id = UUID::Tiny::create_UUID_as_string(UUID_V5, time().$$reply{acct});
+
+	Tweetodon::DB->doINSERT("INSERT INTO users (username, username_sha256, instance, instance_sha256, access_token, session_id) VALUES (?, ?, ?, ?, ?, ?) ON DUPLICATE KEY UPDATE access_token=?, session_id=?", $$reply{acct}, sha256_base64($$reply{acct}), $instance, sha256_base64($instance), $token, $session_id, $token, $session_id);
+
+	$self->{"set_cookie"} = ("session_id=".$session_id);
 }
 
 1;
diff --git a/Tweetodon/Website/Logout.pm b/Tweetodon/Website/Logout.pm
new file mode 100644
index 0000000..8f543a7
--- /dev/null
+++ b/Tweetodon/Website/Logout.pm
@@ -0,0 +1,27 @@
+#!/usr/bin/perl -w
+
+use strict;
+use HTML::Template;
+use Tweetodon::Website;
+
+package Tweetodon::Website::Logout;
+@Tweetodon::Website::Logout::ISA = qw(Tweetodon::Website);
+
+sub requires_authentication {
+	return 0;
+}
+
+sub fill_content {
+	return 1;
+}
+
+sub prerender {
+	my $self = shift;
+	$self->{"template"} = "Login";
+	$self->{"content_type"} = "html";
+	$self->{"params"}->{"currentmode"} = "Login";
+
+	$self->{"set_cookie"} = ("session_id=");
+}
+
+1;
diff --git a/Tweetodon/Website/OAuthLogin.pm b/Tweetodon/Website/OAuthLogin.pm
index 8b0fd75..0a0b32a 100644
--- a/Tweetodon/Website/OAuthLogin.pm
+++ b/Tweetodon/Website/OAuthLogin.pm
@@ -36,18 +36,9 @@ sub prerender {
 	$self->{params}->{instance} = $instance;
 	$self->{params}->{token_is_valid} = "false";
 
-	my $token = $main::FORM{token};
-
-	if (defined($token)){
-		#open(DATA, "./verify_credentials.bash '$token' '$instance'|");
-		#my $reply;
-		#{
-		#$/ = undef;
-		#$reply = <DATA>;
-		#}
-		#close DATA;
-		#$reply = decode_json($reply);
-		if (Tweetodon::User->authenticate()){
+	if (defined($main::FORM{session_id})){
+		my $user = Tweetodon::User->authenticate();
+		if ($user){
 			$self->{params}->{token_is_valid} = "true";
 		}
 		# {"error":"The access token is invalid"}
diff --git a/index.pl b/index.pl
index 53450eb..7c222a2 100755
--- a/index.pl
+++ b/index.pl
@@ -120,7 +120,7 @@ my $object;
 # TODO: This is a very bad solution but not as bad as an uncontrolled eval...
 # The @main::modules array holds a list of all permissible values of the $main::FORM{"mode"} variable.
 # If the value is not in this array, the request is not processed and an error is displayed.
-my @modules = ("Login", "OAuthLogin", "Dashboard", "Callback", "JSON", "EditFeed");
+my @modules = ("Login", "Logout", "OAuthLogin", "Dashboard", "Callback", "JSON", "EditFeed");
 
 if (! grep {$_ eq $FORM{mode}} @modules) {
 	Error("Validation Error", "$FORM{mode} is not a valid module");