less flushing

.clang-tidy

@@ -1 +1 @@
-Checks: '*,clang-analyzer-*,-llvmlibc-*,-fuchsia-*,-altera-*,-abseil-*,-android-*,-modernize-use-trailing-return-type,-readability-identifier-length,-*-readability-todo,-*-magic-numbers,-readability-function-cognitive-complexity,-*-easily-swappable-parameters,-*-pro-type-reinterpret-cast,-*-owning-memory,-concurrency-mt-unsafe,-cert-env33-c,-*-avoid-do-while'
+Checks: '*,clang-analyzer-*,-llvmlibc-*,-fuchsia-*,-altera-*,-abseil-*,-android-*,-boost-*,-modernize-use-trailing-return-type,-readability-identifier-length,-*-readability-todo,-*-magic-numbers,-readability-function-cognitive-complexity,-*-easily-swappable-parameters,-*-pro-type-reinterpret-cast,-*-owning-memory,-concurrency-mt-unsafe,-cert-env33-c,-*-avoid-do-while'

.gitignore

@@ -2,3 +2,5 @@
 /build
 *.py
 *.dull
+/TODO
+/.clangd

CMakeLists.txt

@@ -4,6 +4,11 @@ project(dull)
 set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
+# fix clang
+foreach(flag_var CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_RELEASE CMAKE_CXX_FLAGS_DEBUG)
+    string(REPLACE "-mno-direct-extern-access" "" ${flag_var} "${${flag_var}}")
+endforeach()
+
 find_package(Qt6 REQUIRED COMPONENTS Core Widgets)
 if(NOT WIN32)
     find_package(PkgConfig REQUIRED)
@@ -16,10 +21,9 @@ set(CMAKE_AUTOUIC ON)
 
 qt6_wrap_ui(UI_HEADERS src/mainwindow.ui)
 
-add_executable(${PROJECT_NAME} src/main.cc src/mainwindow.cc src/vault.cc ${UI_HEADERS})
+add_executable(dull src/main.cc src/mainwindow.cc src/vault.cc ${UI_HEADERS})
 
-target_include_directories(${PROJECT_NAME} PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${BOTAN_INCLUDE_DIRS})
+target_include_directories(dull PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${BOTAN_INCLUDE_DIRS})
+target_link_libraries(dull Qt6::Core Qt6::Widgets ${BOTAN_LIBRARIES})
 
-target_link_libraries(${PROJECT_NAME} Qt6::Core Qt6::Widgets ${BOTAN_LIBRARIES})
-
-install(TARGETS ${PROJECT_NAME} DESTINATION bin)
+install(TARGETS dull DESTINATION bin)

LICENSE

@@ -1,4 +1,4 @@
-BSD 3-Clause License
+BSD 2-Clause License
 
 Copyright (c) 2025-2026, Antoni Piasecki
 
@@ -12,10 +12,6 @@ modification, are permitted provided that the following conditions are met:
    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.
 
-3. Neither the name of the copyright holder nor the names of its
-   contributors may be used to endorse or promote products derived from
-   this software without specific prior written permission.
-
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

README.md

@@ -3,9 +3,8 @@
 Desktop app for securely storing sensitive files
 
 ## Features
-* **Pretty usable UI**
-* **Overkill encryption:** XChaCha20-Poly1305 + Argon2id(m=1GB,t=8,p=4) key derivation
 * **Cross-platform:** Tested on Linux, Windows and macOS
+* **Overkill encryption:** XChaCha20-Poly1305 + Argon2id key derivation
 * **Drag and Drop support**
 
 ## Building

src/common.h

@@ -2,39 +2,22 @@
 
 #include <cstdint>
 #include <iostream>
-#include <string>
 
 #define ASSERT(cond)                                                           \
   do {                                                                         \
     if (!(cond)) {                                                             \
       std::cerr << "ASSERTION FAILED at " << __FILE__ << ":" << __LINE__       \
                 << "\n"                                                        \
-                << #cond << std::endl;                                         \
+                << #cond << '\n';                                              \
       abort();                                                                 \
     }                                                                          \
   } while (0)
 
-using u8 = unsigned char;
-using i16 = int16_t;
+using u8 = uint8_t;
 using u16 = uint16_t;
 using i32 = int32_t;
 using u32 = uint32_t;
 using i64 = int64_t;
 using u64 = uint64_t;
-static_assert(sizeof(float) * 8 == 32);
-using f32 = float;
 static_assert(sizeof(double) * 8 == 64);
 using f64 = double;
-
-inline std::string path_to_filename(const std::string &path) {
-  u64 pos = path.find_last_of("/\\");
-  return (pos == std::string::npos) ? path : path.substr(pos + 1);
-}
-
-template <typename T> constexpr char *to_char_ptr(T *ptr) noexcept {
-  return reinterpret_cast<char *>(ptr);
-}
-
-template <typename T> constexpr const char *to_char_ptr(const T *ptr) noexcept {
-  return reinterpret_cast<const char *>(ptr);
-}

src/crypto.h

@@ -1,57 +1,63 @@
 #pragma once
 #include "common.h"
+#include <algorithm>
 #include <botan/aead.h>
+#include <botan/auto_rng.h>
 #include <botan/pwdhash.h>
 
 namespace Crypto {
 
-inline Botan::secure_vector<u8>
-encrypt_xchacha20_poly1305(const Botan::secure_vector<u8> &plaintext,
-                           const Botan::secure_vector<u8> &key,
-                           const std::array<u8, 24> &nonce) {
+inline Botan::secure_vector<u8> encrypt(const Botan::secure_vector<u8> &key,
+                                        const std::span<const u8> &plaintext) {
   ASSERT(key.size() == 32);
-  ASSERT(nonce.size() == 24);
+
+  static Botan::AutoSeeded_RNG rng;
 
   // XChaCha20 is selected automatically based on the nonce size
   // https://github.com/randombit/botan/blob/master/src/lib/stream/chacha/chacha.cpp#L375
-  auto cipher = Botan::AEAD_Mode::create_or_throw(
+  static thread_local auto cipher = Botan::AEAD_Mode::create_or_throw(
       "ChaCha20Poly1305", Botan::Cipher_Dir::Encryption);
+  cipher->clear();
+
+  auto nonce = rng.random_array<24>();
+  cipher->set_key(key);
+  cipher->start(nonce);
+
+  Botan::secure_vector<u8> res;
+  res.resize(24 + plaintext.size());
+  std::ranges::copy(nonce, res.begin());
+  std::ranges::copy(plaintext, res.begin() + 24);
+  cipher->finish(res, 24);
+  return res;
+}
+
+inline Botan::secure_vector<u8>
+decrypt(const Botan::secure_vector<u8> &key,
+        const Botan::secure_vector<u8> &ciphertext_with_nonce) {
+  ASSERT(ciphertext_with_nonce.size() >= 40);
+  ASSERT(key.size() == 32);
+
+  std::array<u8, 24> nonce{};
+  std::copy_n(ciphertext_with_nonce.begin(), 24, nonce.begin());
+
+  static thread_local auto cipher = Botan::AEAD_Mode::create_or_throw(
+      "ChaCha20Poly1305", Botan::Cipher_Dir::Decryption);
+  cipher->clear();
 
   cipher->set_key(key);
   cipher->start(nonce);
 
-  Botan::secure_vector<u8> ciphertext = plaintext;
+  Botan::secure_vector<u8> ciphertext(ciphertext_with_nonce.begin() + 24,
+                                      ciphertext_with_nonce.end());
   cipher->finish(ciphertext);
 
   return ciphertext;
 }
 
-inline Botan::secure_vector<u8>
-decrypt_xchacha20_poly1305(const Botan::secure_vector<u8> &ciphertext,
-                           const Botan::secure_vector<u8> &key,
-                           const std::array<u8, 24> &nonce) {
-  ASSERT(ciphertext.size() >= 16);
-  ASSERT(key.size() == 32);
-  ASSERT(nonce.size() == 24);
-
-  auto cipher = Botan::AEAD_Mode::create_or_throw(
-      "ChaCha20Poly1305", Botan::Cipher_Dir::Decryption);
-
-  cipher->set_key(key);
-  cipher->start(nonce);
-
-  Botan::secure_vector<u8> plaintext = ciphertext;
-  cipher->finish(plaintext);
-
-  return plaintext;
-}
-
-inline Botan::secure_vector<u8>
-derive_key_argon2id(const std::string &password,
+inline Botan::secure_vector<u8> derive_key(const std::string &password,
                                            const std::array<u8, 16> &salt) {
-  // thousands of years to crack a random 8 char password on a 100 GPUs
   auto pwdhash = Botan::PasswordHashFamily::create_or_throw("Argon2id")
-                     ->from_params(static_cast<u64>(1024 * 1024), 8, 4);
+                     ->from_params(static_cast<u64>(512 * 1024), 8, 4);
 
   Botan::secure_vector<u8> key(32);
   pwdhash->derive_key(key.data(), key.size(), password.data(), password.size(),

src/mainwindow.cc

@@ -1,6 +1,5 @@
 // TODO: actual fs
 #include "mainwindow.h"
-#include "crypto.h"
 #include <QDesktopServices>
 #include <QDropEvent>
 #include <QFileDialog>
@@ -8,8 +7,33 @@
 #include <QMessageBox>
 #include <QMimeData>
 #include <QTemporaryDir>
-#include <botan/auto_rng.h>
+#include <array>
 #include <botan/exceptn.h>
+#include <stdexcept>
+
+namespace {
+
+std::string basename(const std::string &path) {
+  u64 pos = path.find_last_of("/\\");
+  return (pos == std::string::npos) ? path : path.substr(pos + 1);
+}
+
+std::string format_bytes(u64 bytes) {
+  const std::array<std::string_view, 5> units = {"B", "KB", "MB", "GB", "TB"};
+  auto size = static_cast<f64>(bytes);
+  i32 unit = 0;
+
+  while (size >= 1024.0 && unit < 5) {
+    size /= 1024.0;
+    ++unit;
+  }
+
+  std::ostringstream out;
+  out << std::fixed << std::setprecision(2) << size << " " << units.at(unit);
+  return out.str();
+}
+
+} // namespace
 
 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent), ui(std::make_unique<Ui::MainWindow>()) {
@@ -31,42 +55,27 @@ MainWindow::MainWindow(QWidget *parent)
       path += ".dull";
     }
 
-    QString password = QInputDialog::getText(
+    QString password;
+    while (true) {
+      password = QInputDialog::getText(
           this, "Choose a password", "Choose a password", QLineEdit::Password);
       if (password.length() < 8) {
         QMessageBox::critical(this, "Error",
                               "Password must be at least 8 characters long.");
-      return;
+      } else {
+        break;
+      }
     }
 
     ui->statusbar->showMessage("Creating the vault...");
     QCoreApplication::processEvents();
 
-    static Botan::AutoSeeded_RNG rng;
-    auto salt = rng.random_array<16>();
-
-    auto key = Crypto::derive_key_argon2id(password.toStdString(), salt);
-    auto check_nonce = rng.random_array<24>();
-
-    const std::string content = "LETSGO";
-    Botan::secure_vector<u8> content_sv(content.begin(), content.end());
-    auto check_ciphertext =
-        Crypto::encrypt_xchacha20_poly1305(content_sv, key, check_nonce);
-
-    std::ofstream create(path.toStdString(), std::ios::binary);
-    create.write("DULL", 4);
-    create.write(to_char_ptr(&VERSION), sizeof(VERSION));
-    create.write(to_char_ptr(salt.data()), 16);
-
-    create.write(to_char_ptr(check_nonce.data()), 24);
-    create.write(to_char_ptr(check_ciphertext.data()), 22);
-    create.close();
-
     m_vault =
-        std::make_unique<Vault>(path.toStdString(), password.toStdString());
-    reload_fs_tree();
+        Vault::create_and_open(path.toStdString(), password.toStdString());
 
-    ui->statusbar->clearMessage();
+    ui->statusbar->showMessage("Opened " + path);
+
+    reload_fs_tree();
   });
 
   connect(ui->actionOpen, &QAction::triggered, this, [this]() {
@@ -90,7 +99,7 @@ MainWindow::MainWindow(QWidget *parent)
       m_vault =
           std::make_unique<Vault>(path.toStdString(), password.toStdString());
       reload_fs_tree();
-      ui->statusbar->clearMessage();
+      ui->statusbar->showMessage("Opened " + path);
     } catch (const Botan::Invalid_Authentication_Tag &e) {
       QMessageBox::critical(this, "Error", "Invalid password.");
       ui->statusbar->clearMessage();
@@ -113,13 +122,18 @@ MainWindow::MainWindow(QWidget *parent)
     QStringList paths =
         QFileDialog::getOpenFileNames(this, "Choose files to add");
     for (const auto &path : paths) {
-      std::ifstream file(path.toStdString(), std::ios::binary);
+      ui->statusbar->showMessage("Adding " + path + "...");
+      QCoreApplication::processEvents();
 
-      std::string content((std::istreambuf_iterator<char>(file)),
-                          std::istreambuf_iterator<char>());
-
-      m_vault->create_file(path_to_filename(path.toStdString()), content);
+      std::ifstream file(path.toStdString(), std::ios::binary | std::ios::ate);
+      ASSERT(file.good());
+      auto size = file.tellg();
+      file.seekg(0);
+      std::string content(size, '\0');
+      file.read(content.data(), size);
+      m_vault->create_file(basename(path.toStdString()), content);
     }
+    m_vault->flush();
 
     reload_fs_tree();
     ui->statusbar->showMessage("Added " + QString::number(paths.size()) +
@@ -137,14 +151,14 @@ MainWindow::MainWindow(QWidget *parent)
       return;
     }
 
-    auto headers = m_vault->read_file_headers();
-    for (const auto &header : headers) {
-      auto content = m_vault->read_file(header.name);
-      if (content) {
-        std::ofstream file(path.toStdString() + "/" + header.name,
-                           std::ios::binary);
-        file.write(content->data(), static_cast<i64>(content->size()));
-      }
+    const auto &file_map = m_vault->file_map();
+    for (const auto &[k, _] : file_map) {
+      auto content = m_vault->read_file(k);
+      ui->statusbar->showMessage("Extracting " + QString::fromStdString(k) +
+                                 "...");
+      QCoreApplication::processEvents();
+      std::ofstream file(path.toStdString() + "/" + k, std::ios::binary);
+      file.write(content.data(), static_cast<i64>(content.size()));
     }
     ui->statusbar->showMessage("Extracted all files to " + path);
   });
@@ -155,12 +169,13 @@ void MainWindow::reload_fs_tree() {
   ui->menuFiles->setEnabled(true);
   ui->fsTreeWidget->clear();
 
-  auto headers = m_vault->read_file_headers();
-  for (const auto &header : headers) {
+  const auto &file_map = m_vault->file_map();
+  for (const auto &[k, v] : file_map) {
     auto *item = new QTreeWidgetItem(ui->fsTreeWidget);
     item->setIcon(0, style()->standardIcon(QStyle::SP_FileIcon));
-    item->setText(0, QString::fromStdString(header.name));
-    item->setText(1, QString::number(header.content_ciphertext_size));
+    item->setText(0, QString::fromStdString(k));
+    item->setText(
+        1, QString::fromStdString(format_bytes(v.content_ciphertext_size)));
   }
   for (int i = 0; i < ui->fsTreeWidget->columnCount(); ++i) {
     ui->fsTreeWidget->resizeColumnToContents(i);
@@ -170,17 +185,17 @@ void MainWindow::reload_fs_tree() {
 void MainWindow::preview_file(const std::string &filename) {
   ui->filePreview->setVisible(true);
 
+  try {
     auto content = m_vault->read_file(filename);
-  if (content) {
-    ui->filePreview->setText(QString::fromStdString(content.value()));
-  } else {
+    ui->filePreview->setText(QString::fromStdString(content));
+  } catch (std::out_of_range &) {
     qWarning() << "File to preview not found";
   }
 }
 
 void MainWindow::extract_file(const std::string &filename) {
+  try {
     auto content = m_vault->read_file(filename);
-  if (content) {
     QString path = QFileDialog::getSaveFileName(
         this, "Choose location to extract",
         QDir::currentPath() + "/" + QString::fromStdString(filename));
@@ -189,24 +204,47 @@ void MainWindow::extract_file(const std::string &filename) {
     }
 
     std::ofstream file(path.toStdString(), std::ios::binary);
-    file.write(content->data(), static_cast<i64>(content->size()));
+    file.write(content.data(), static_cast<i64>(content.size()));
 
     ui->statusbar->showMessage("Extracted to " + path);
-  } else {
+  } catch (std::out_of_range &) {
     qWarning() << "File to extract not found";
   }
 }
 
-void MainWindow::edit_file(const std::string &filename) {
+void MainWindow::open_file(const std::string &filename) {
+  try {
     auto content = m_vault->read_file(filename);
-  if (content) {
     QTemporaryDir dir;
     ASSERT(dir.isValid());
 
     std::string path = dir.path().toStdString() + "/" + filename;
 
     std::ofstream file(path);
-    file.write(content->data(), static_cast<i64>(content->size()));
+    file.write(content.data(), static_cast<i64>(content.size()));
+    file.close();
+
+    QDesktopServices::openUrl(
+        QUrl::fromLocalFile(QString::fromStdString(path)));
+    QMessageBox::information(this, "Open",
+                             "Click OK to delete the opened file.");
+
+    // QTemporaryDir gets deleted when it goes out of scope
+  } catch (std::out_of_range &) {
+    qWarning() << "File to open not found";
+  }
+}
+
+void MainWindow::edit_file(const std::string &filename) {
+  try {
+    auto content = m_vault->read_file(filename);
+    QTemporaryDir dir;
+    ASSERT(dir.isValid());
+
+    std::string path = dir.path().toStdString() + "/" + filename;
+
+    std::ofstream file(path);
+    file.write(content.data(), static_cast<i64>(content.size()));
     file.close();
 
     QDesktopServices::openUrl(
@@ -215,16 +253,18 @@ void MainWindow::edit_file(const std::string &filename) {
                              "Please edit the file in the opened editor and "
                              "save it. Click OK when done.");
 
-    std::ifstream file2(path, std::ios::binary);
-    std::string new_content((std::istreambuf_iterator<char>(file2)),
-                            std::istreambuf_iterator<char>());
-
+    std::ifstream file2(path, std::ios::binary | std::ios::ate);
+    ASSERT(file2.good());
+    auto size = file2.tellg();
+    file2.seekg(0);
+    std::string new_content(size, '\0');
+    file2.read(new_content.data(), size);
     m_vault->update_file(filename, new_content);
     reload_fs_tree();
 
     ui->statusbar->showMessage("File updated");
     // QTemporaryDir gets deleted when it goes out of scope
-  } else {
+  } catch (std::out_of_range &) {
     qWarning() << "File to edit not found";
   }
 }
@@ -237,13 +277,21 @@ void MainWindow::file_context_menu(const QPoint &pos) {
 
   QMenu menu(this);
 
-  QAction *preview_action = menu.addAction(
-      style()->standardIcon(QStyle::SP_FileDialogContentsView), "Preview");
+  QAction *preview_action =
+      menu.addAction(style()->standardIcon(QStyle::SP_FileDialogContentsView),
+                     "Preview as text");
   connect(preview_action, &QAction::triggered, this,
           [this, item]() { preview_file(item->text(0).toStdString()); });
 
-  QAction *edit_action = menu.addAction(
-      style()->standardIcon(QStyle::SP_FileDialogDetailedView), "Edit");
+  QAction *open_action =
+      menu.addAction(style()->standardIcon(QStyle::SP_FileDialogDetailedView),
+                     "Open in external app");
+  connect(open_action, &QAction::triggered, this,
+          [this, item]() { open_file(item->text(0).toStdString()); });
+
+  QAction *edit_action =
+      menu.addAction(style()->standardIcon(QStyle::SP_FileDialogDetailedView),
+                     "Edit in external app");
   connect(edit_action, &QAction::triggered, this,
           [this, item]() { edit_file(item->text(0).toStdString()); });
 
@@ -256,6 +304,7 @@ void MainWindow::file_context_menu(const QPoint &pos) {
       style()->standardIcon(QStyle::SP_DialogCancelButton), "Delete");
   connect(delete_action, &QAction::triggered, this, [this, item]() {
     m_vault->delete_file(item->text(0).toStdString());
+    m_vault->flush();
     reload_fs_tree();
   });
 
@@ -288,15 +337,17 @@ void MainWindow::dropEvent(QDropEvent *event) {
     if (!u.isLocalFile()) {
       continue;
     }
-    std::ifstream file(u.toLocalFile().toStdString(), std::ios::binary);
+
+    std::ifstream file(u.toLocalFile().toStdString(),
+                       std::ios::binary | std::ios::ate);
     ASSERT(file.good());
-
-    std::string content((std::istreambuf_iterator<char>(file)),
-                        std::istreambuf_iterator<char>());
-
-    m_vault->create_file(path_to_filename(u.toLocalFile().toStdString()),
-                         content);
+    auto size = file.tellg();
+    file.seekg(0);
+    std::string content(size, '\0');
+    file.read(content.data(), size);
+    m_vault->create_file(basename(u.toLocalFile().toStdString()), content);
   }
+  m_vault->flush();
   ui->statusbar->showMessage(
       "Added " + QString::number(event->mimeData()->urls().size()) + " files");
   reload_fs_tree();

src/mainwindow.h

@@ -21,6 +21,7 @@ private:
   void reload_fs_tree();
   void preview_file(const std::string &filename);
   void extract_file(const std::string &filename);
+  void open_file(const std::string &filename);
   void edit_file(const std::string &filename);
   void file_context_menu(const QPoint &pos);
 };

src/vault.cc

@@ -2,7 +2,25 @@
 #include "common.h"
 #include "crypto.h"
 #include <botan/auto_rng.h>
-#include <filesystem>
+
+#define WRITE(file, data, size)                                                \
+  ASSERT(file.write(to_char_ptr(data), static_cast<i64>(size)))
+
+namespace {
+
+template <typename T> constexpr char *to_char_ptr(T *ptr) noexcept {
+  return reinterpret_cast<char *>(ptr);
+}
+
+template <typename T> constexpr const char *to_char_ptr(const T *ptr) noexcept {
+  return reinterpret_cast<const char *>(ptr);
+}
+
+template <typename T> constexpr std::span<const u8> to_span(const T &x) {
+  return std::span<const u8>(reinterpret_cast<const u8 *>(x.data()), x.size());
+}
+
+} // namespace
 
 Vault::Vault(std::string path, const std::string &password)
     : m_path(std::move(path)) {
@@ -13,27 +31,46 @@ Vault::Vault(std::string path, const std::string &password)
   ASSERT(m_file.read(magic.data(), 4));
   ASSERT(std::string_view(magic.data(), magic.size()) == "DULL");
 
-  i16 version = 0;
+  u16 version = 0;
   ASSERT(m_file.read(to_char_ptr(&version), sizeof(version)));
   ASSERT(version == VERSION);
 
   std::array<u8, 16> salt{};
   ASSERT(m_file.read(to_char_ptr(salt.data()), 16));
 
-  m_key = Crypto::derive_key_argon2id(password, salt);
-
-  std::array<u8, 24> check_nonce{};
-  ASSERT(m_file.read(to_char_ptr(check_nonce.data()), 24));
+  m_key = Crypto::derive_key(password, salt);
 
   Botan::secure_vector<u8> check_ciphertext;
-  check_ciphertext.resize(22);
-  ASSERT(m_file.read(to_char_ptr(check_ciphertext.data()), 22));
+  check_ciphertext.resize(46);
+  ASSERT(m_file.read(to_char_ptr(check_ciphertext.data()), 46));
 
-  Crypto::decrypt_xchacha20_poly1305(check_ciphertext, m_key, check_nonce);
+  Crypto::decrypt(m_key, check_ciphertext);
+
+  build_file_map();
 }
 
-std::vector<FileHeader> Vault::read_file_headers() {
-  std::vector<FileHeader> headers;
+std::unique_ptr<Vault> Vault::create_and_open(const std::string &path,
+                                              const std::string &password) {
+  static Botan::AutoSeeded_RNG rng;
+  auto salt = rng.random_array<16>();
+
+  auto key = Crypto::derive_key(password, salt);
+
+  const std::string_view content = "LETSGO";
+  auto check_ciphertext = Crypto::encrypt(key, to_span(content));
+
+  std::ofstream file(path, std::ios::binary);
+  WRITE(file, "DULL", 4);
+  WRITE(file, to_char_ptr(&VERSION), sizeof(VERSION));
+  WRITE(file, to_char_ptr(salt.data()), 16);
+  WRITE(file, to_char_ptr(check_ciphertext.data()), 46);
+  file.close();
+
+  return std::make_unique<Vault>(path, password);
+}
+
+void Vault::build_file_map() {
+  m_file_map.clear();
 
   m_file.clear();
   m_file.seekg(AFTER_HEADER_OFFSET, std::ios::beg);
@@ -41,147 +78,99 @@ std::vector<FileHeader> Vault::read_file_headers() {
   while (true) {
     auto header = read_file_header();
     if (header) {
-      headers.push_back(header.value());
+      if (!header->deleted) {
+        m_file_map[header->name] = header.value();
+      }
       m_file.seekg(static_cast<i64>(header->content_ciphertext_size),
                    std::ios::cur);
     } else {
       break;
     }
   }
-
-  return headers;
 }
 
-std::optional<std::string> Vault::read_file(const std::string &filename) {
+std::string Vault::read_file(const std::string &name) {
+  auto header = m_file_map.at(name);
+  ASSERT(!header.deleted);
+
   m_file.clear();
-  m_file.seekg(AFTER_HEADER_OFFSET, std::ios::beg);
+  m_file.seekg(static_cast<i64>(header.content_offset), std::ios::beg);
 
-  while (true) {
-    auto header = read_file_header();
-    if (!header) {
-      break;
-    }
-
-    if (header->name == filename) {
   Botan::secure_vector<u8> ciphertext;
-      ciphertext.resize(header->content_ciphertext_size);
-      if (!m_file.read(to_char_ptr(ciphertext.data()),
-                       static_cast<i64>(header->content_ciphertext_size))) {
-        break;
+  ciphertext.resize(header.content_ciphertext_size);
+  ASSERT(m_file.read(to_char_ptr(ciphertext.data()),
+                     static_cast<i64>(header.content_ciphertext_size)));
+
+  auto plaintext = Crypto::decrypt(m_key, ciphertext);
+  return {to_char_ptr(plaintext.data()), plaintext.size()};
 }
 
-      auto plaintext = Crypto::decrypt_xchacha20_poly1305(
-          ciphertext, m_key, header->content_nonce);
-      return std::string(to_char_ptr(plaintext.data()), plaintext.size());
-    }
+void Vault::create_file(const std::string &name, const std::string &content) {
+  ASSERT(!m_file_map.contains(name));
 
-    m_file.seekg(static_cast<i64>(header->content_ciphertext_size),
-                 std::ios::cur);
-  }
-
-  return std::nullopt;
-}
-
-void Vault::create_file(const std::string &filename,
-                        const std::string &content) {
   m_file.clear();
   m_file.seekp(0, std::ios::end);
 
-  static Botan::AutoSeeded_RNG rng;
-  auto name_nonce = rng.random_array<24>();
-  auto content_nonce = rng.random_array<24>();
+  auto offset = m_file.tellp();
 
-  Botan::secure_vector<u8> filename_sv(filename.begin(), filename.end());
-  auto filename_ciphertext =
-      Crypto::encrypt_xchacha20_poly1305(filename_sv, m_key, name_nonce);
-  u64 filename_ciphertext_size = filename_ciphertext.size();
+  auto name_ciphertext = Crypto::encrypt(m_key, to_span(name));
+  u64 name_ciphertext_size = name_ciphertext.size();
 
-  Botan::secure_vector<u8> content_sv(content.begin(), content.end());
-  auto ciphertext =
-      Crypto::encrypt_xchacha20_poly1305(content_sv, m_key, content_nonce);
+  auto ciphertext = Crypto::encrypt(m_key, to_span(content));
   u64 ciphertext_size = ciphertext.size();
 
-  ASSERT(m_file.write(to_char_ptr(name_nonce.data()), name_nonce.size()));
-  ASSERT(m_file.write(to_char_ptr(&filename_ciphertext_size), sizeof(u64)));
-  ASSERT(m_file.write(to_char_ptr(filename_ciphertext.data()),
-                      static_cast<i64>(filename_ciphertext_size)));
-  ASSERT(m_file.write(to_char_ptr(content_nonce.data()), content_nonce.size()));
-  ASSERT(m_file.write(to_char_ptr(&ciphertext_size), sizeof(u64)));
-  ASSERT(m_file.write(to_char_ptr(ciphertext.data()),
-                      static_cast<i64>(ciphertext_size)));
-  m_file.flush();
+  bool deleted = false;
+  WRITE(m_file, &deleted, sizeof(bool)); // deleted flag
+  WRITE(m_file, &name_ciphertext_size, sizeof(u64));
+  WRITE(m_file, name_ciphertext.data(), name_ciphertext_size);
+  WRITE(m_file, &ciphertext_size, sizeof(u64));
+  auto content_offset = m_file.tellp();
+  WRITE(m_file, ciphertext.data(), ciphertext_size);
+
+  m_file_map[name] = FileHeader{
+      .offset = static_cast<u64>(offset),
+      .deleted = false,
+      .name_ciphertext_size = name_ciphertext_size,
+      .name = name,
+      .content_ciphertext_size = ciphertext_size,
+      .content_offset = static_cast<u64>(content_offset),
+  };
 }
 
-void Vault::delete_file(const std::string &filename) {
+void Vault::delete_file(const std::string &name) {
+  auto header = m_file_map.at(name);
+
+  // zero the ciphertext and mark as deleted
   m_file.clear();
-  m_file.seekg(AFTER_HEADER_OFFSET, std::ios::beg);
-
-  i64 entry_start = -1;
-  u64 entry_total_size = 0;
-
-  while (true) {
-    i64 current_pos = m_file.tellg();
-
-    auto header = read_file_header();
-    if (!header) {
-      break;
+  m_file.seekp(static_cast<i64>(header.content_offset), std::ios::beg);
+  std::array<u8, 4096> zeros = {0};
+  u64 remaining = header.content_ciphertext_size;
+  while (remaining > 0) {
+    u64 chunk = std::min(remaining, sizeof(zeros));
+    WRITE(m_file, zeros.data(), chunk);
+    remaining -= chunk;
   }
 
-    if (header->name == filename) {
-      entry_start = current_pos;
-      entry_total_size = 24 + sizeof(u64) + header->name_ciphertext_size + 24 +
-                         sizeof(u64) + header->content_ciphertext_size;
-      m_file.seekg(static_cast<i64>(header->content_ciphertext_size),
-                   std::ios::cur);
-      break;
-    }
-
-    m_file.seekg(static_cast<i64>(header->content_ciphertext_size),
-                 std::ios::cur);
-  }
-
-  if (entry_start != -1) {
-    i64 entry_end = entry_start + static_cast<i64>(entry_total_size);
-
-    i64 read_pos = entry_end;
-    i64 write_pos = entry_start;
-    std::array<u8, 65536> buffer{};
-    while (true) {
   m_file.clear();
-      m_file.seekg(read_pos);
-      m_file.read(to_char_ptr(buffer.data()), buffer.size());
-      auto bytes = m_file.gcount();
-      if (bytes == 0) {
-        break;
+  m_file.seekp(static_cast<i64>(header.offset), std::ios::beg);
+  bool deleted = true;
+  WRITE(m_file, &deleted, sizeof(bool));
+
+  m_file_map.erase(name);
 }
 
-      m_file.seekp(write_pos);
-      ASSERT(m_file.write(to_char_ptr(buffer.data()), bytes));
-
-      read_pos += bytes;
-      write_pos += bytes;
-    }
-
-    m_file.flush();
-    m_file.close();
-
-    std::filesystem::resize_file(m_path, write_pos);
-
-    m_file.open(m_path, std::ios::in | std::ios::out | std::ios::binary);
-    ASSERT(m_file.good());
-  }
-}
-
-void Vault::update_file(const std::string &filename,
-                        const std::string &content) {
-  delete_file(filename);
-  create_file(filename, content);
+void Vault::update_file(const std::string &name, const std::string &content) {
+  delete_file(name);
+  create_file(name, content);
+  flush();
 }
 
 std::optional<FileHeader> Vault::read_file_header() {
   FileHeader header{};
 
-  if (!m_file.read(to_char_ptr(header.name_nonce.data()), 24)) {
+  header.offset = m_file.tellg();
+
+  if (!m_file.read(to_char_ptr(&header.deleted), 1)) {
     return std::nullopt;
   }
 
@@ -198,16 +187,15 @@ std::optional<FileHeader> Vault::read_file_header() {
     return std::nullopt;
   }
 
-  auto name = Crypto::decrypt_xchacha20_poly1305(name_ciphertext, m_key,
-                                                 header.name_nonce);
+  if (!header.deleted) {
+    auto name = Crypto::decrypt(m_key, name_ciphertext);
     header.name = std::string(name.begin(), name.end());
-
-  if (!m_file.read(to_char_ptr(header.content_nonce.data()), 24)) {
-    return std::nullopt;
   }
 
   if (!m_file.read(to_char_ptr(&header.content_ciphertext_size), sizeof(u64))) {
     return std::nullopt;
   }
+
+  header.content_offset = m_file.tellg();
   return header;
 }

src/vault.h

@@ -1,39 +1,48 @@
 #pragma once
 
 #include "common.h"
-#include <array>
 #include <botan/secmem.h>
 #include <fstream>
+#include <memory>
 #include <optional>
+#include <unordered_map>
 
-constexpr i16 VERSION = 1;
+constexpr u16 VERSION = 1;
 constexpr u64 AFTER_HEADER_OFFSET = 68;
 
-// !!! REMEMBER TO UPDATE entry_total_size IN Vault::delete_file
 struct FileHeader {
-  std::array<u8, 24> name_nonce;
+  u64 offset;
+  bool deleted;
   u64 name_ciphertext_size;
   std::string name;
-  std::array<u8, 24> content_nonce;
   u64 content_ciphertext_size;
+  u64 content_offset;
 };
 
 class Vault {
 public:
   explicit Vault(std::string path, const std::string &password);
 
-  std::vector<FileHeader> read_file_headers();
-  std::optional<std::string> read_file(const std::string &name);
+  static std::unique_ptr<Vault> create_and_open(const std::string &path,
+                                                const std::string &password);
+
+  std::string read_file(const std::string &name);
   void create_file(const std::string &name, const std::string &content);
   void delete_file(const std::string &name);
   void update_file(const std::string &name, const std::string &content);
+  void flush() { m_file.flush(); }
 
   const std::string &path() const { return m_path; }
+  const std::unordered_map<std::string, FileHeader> &file_map() const {
+    return m_file_map;
+  }
 
 private:
   std::string m_path;
   std::fstream m_file;
   Botan::secure_vector<u8> m_key;
+  std::unordered_map<std::string, FileHeader> m_file_map;
 
+  void build_file_map();
   std::optional<FileHeader> read_file_header();
 };