This should be a first proper version

main.cpp

@@ -31,6 +31,16 @@ void print_help()
 	cout << "The following commands are available: help, login, register, exit" << endl;
 }
 
+void print_flag()
+{
+	PROFILER_RECORD;
+	ifstream file("flag.txt");
+	string flag;
+	getline(file, flag);
+	cout << flag << endl;
+	exit(0);
+}
+
 void login()
 {
 	PROFILER_RECORD;
@@ -38,20 +48,35 @@ void login()
 	string username = prompt(':');
 	cout << "Password";
 	string password = prompt(':');
-	uint8_t encrypted_password[16];
+	if (username != "admin")
+	{
+		cout << "Unknown user '" << username << "'" << endl;
+		return;
+	}
 	if (password.length() != 16)
 	{
 		cout << "Password format error" << endl;
 		return;
 	}
+	uint8_t encrypted_password[16];
 	for (int i = 0;i < 16;i++)
 	{
 		encrypted_password[i] = password[i];
 	}
 	AES::encrypt_ecb(encrypted_password, key);
-	// TODO Validate encrypted password
+	uint8_t rootpw[16] = {0xe3, 0x07, 0x2e, 0x9f, 0x5b, 0xe8, 0xed, 0xd6, 0x02, 0xab, 0x89, 0xb8, 0xeb, 0x49, 0xcc, 0x56};
+	for (int i = 0;i < 16;i++)
+	{
+		if (encrypted_password[i] != rootpw[i])
+		{
+			cout << "Invalid password" << endl;
+			return;
+		}
+	}
+	print_flag();
 }
 
+#include <iomanip>
 void register_user()
 {
 	PROFILER_RECORD;
@@ -86,7 +111,10 @@ bool execute_command(const string &input)
 	{
 		profiler.reset();
 	}
-	cout << "Invalid command '" << input << "'" << endl;
+	else
+	{
+		cout << "Invalid command '" << input << "'" << endl;
+	}
 	return true;
 }