From d02476ac65a8b0f7341c06a3501340d7a8647912 Mon Sep 17 00:00:00 2001
From: Egor Tensin <egor@tensin.name>
Date: Fri, 24 Jul 2026 12:22:42 +0200
Subject: aesxx: factor out key stuff into key.hpp

---
 aesxx/include/aesxx/box.hpp   | 22 +++++++------------
 aesxx/include/aesxx/key.hpp   | 49 +++++++++++++++++++++++++++++++++++++++++++
 aesxx/utils/decrypt_block.cpp |  4 +---
 aesxx/utils/decrypt_bmp.cpp   |  4 +---
 aesxx/utils/decrypt_file.cpp  |  4 +---
 aesxx/utils/encrypt_block.cpp |  4 +---
 aesxx/utils/encrypt_bmp.cpp   |  4 +---
 aesxx/utils/encrypt_file.cpp  |  4 +---
 8 files changed, 63 insertions(+), 32 deletions(-)
 create mode 100644 aesxx/include/aesxx/key.hpp

diff --git a/aesxx/include/aesxx/box.hpp b/aesxx/include/aesxx/box.hpp
index e625f38..aac2162 100644
--- a/aesxx/include/aesxx/box.hpp
+++ b/aesxx/include/aesxx/box.hpp
@@ -8,6 +8,7 @@
 #include "algorithm.hpp"
 #include "block.hpp"
 #include "error.hpp"
+#include "key.hpp"
 #include "mode.hpp"
 
 #include <aes/all.h>
@@ -22,12 +23,6 @@ namespace aes {
 
 class Box {
 public:
-    using Key = AES_Key;
-
-    static void parse_key(Key& dest, Algorithm algorithm, std::string_view src) {
-        aes_parse_key(algorithm, &dest, src.data(), ErrorDetailsThrowsInDestructor{});
-    }
-
     Box(Algorithm algorithm,
         const Key& key,
         Mode mode,
@@ -35,7 +30,12 @@ public:
         bool verbose = false)
         : verbose{verbose} {
         aes_box_init(
-            &impl, algorithm, &key, mode, iv ? iv->ptr() : NULL, ErrorDetailsThrowsInDestructor{}
+            &impl,
+            algorithm,
+            key.ptr(),
+            mode,
+            iv ? iv->ptr() : NULL,
+            ErrorDetailsThrowsInDestructor{}
         );
         dump_key(key);
     }
@@ -113,15 +113,9 @@ public:
     }
 
 private:
-    static std::string format_key(const Key& src, Algorithm algorithm) {
-        AES_KeyString str;
-        aes_format_key(algorithm, &str, &src, ErrorDetailsThrowsInDestructor{});
-        return reinterpret_cast<const char*>(&str);
-    }
-
     void dump_key(const Key& src) const {
         if (verbose)
-            std::cout << std::format("Key         : {}\n", format_key(src, get_algorithm()));
+            std::cout << std::format("Key         : {}\n", src.to_string());
     }
 
     Block get_iv() const {
diff --git a/aesxx/include/aesxx/key.hpp b/aesxx/include/aesxx/key.hpp
new file mode 100644
index 0000000..7036814
--- /dev/null
+++ b/aesxx/include/aesxx/key.hpp
@@ -0,0 +1,49 @@
+// Copyright (c) 2015 Egor Tensin <egor@tensin.name>
+// This file is part of the "AES tools" project.
+// For details, see https://github.com/egor-tensin/aes-tools.
+// Distributed under the MIT License.
+
+#pragma once
+
+#include "algorithm.hpp"
+#include "error.hpp"
+
+#include <aes/all.h>
+
+#include <string>
+#include <string_view>
+
+namespace aes {
+
+class Key {
+public:
+    using Impl = AES_Key;
+
+    static Key parse(std::string_view src, Algorithm algorithm) {
+        Impl dest;
+        aes_parse_key(algorithm, &dest, src.data(), ErrorDetailsThrowsInDestructor{});
+        return Key{dest, algorithm};
+    }
+
+    explicit Key(const Impl& impl, Algorithm algorithm) : impl{impl}, algorithm{algorithm} {}
+
+    Impl* ptr() {
+        return &impl;
+    }
+
+    const Impl* ptr() const {
+        return &impl;
+    }
+
+    std::string to_string() const {
+        AES_KeyString str;
+        aes_format_key(algorithm, &str, &impl, ErrorDetailsThrowsInDestructor{});
+        return reinterpret_cast<const char*>(&str);
+    }
+
+private:
+    Impl impl;
+    Algorithm algorithm;
+};
+
+} // namespace aes
diff --git a/aesxx/utils/decrypt_block.cpp b/aesxx/utils/decrypt_block.cpp
index 9f9ee2a..d1dd059 100644
--- a/aesxx/utils/decrypt_block.cpp
+++ b/aesxx/utils/decrypt_block.cpp
@@ -23,9 +23,7 @@ void decrypt_blocks(
     const BlockSettings::Input& input,
     bool verbose = false
 ) {
-    aes::Box::Key key;
-    aes::Box::parse_key(key, algorithm, input.get_key());
-
+    const auto key = aes::Key::parse(input.get_key(), algorithm);
     aes::Box box{algorithm, key, mode, input.get_iv(), verbose};
 
     for (const auto& ciphertext : input.get_blocks()) {
diff --git a/aesxx/utils/decrypt_bmp.cpp b/aesxx/utils/decrypt_bmp.cpp
index e78adfc..384c32d 100644
--- a/aesxx/utils/decrypt_bmp.cpp
+++ b/aesxx/utils/decrypt_bmp.cpp
@@ -33,9 +33,7 @@ void decrypt_bmp(
 void decrypt_bmp(const FileSettings& settings) {
     const auto algorithm = settings.get_algorithm();
     const auto mode = settings.get_mode();
-
-    aes::Box::Key key;
-    aes::Box::parse_key(key, algorithm, settings.get_key());
+    const auto key = aes::Key::parse(settings.get_key(), algorithm);
 
     aes::Box box{algorithm, key, mode, settings.get_iv()};
     decrypt_bmp(box, settings.get_input_path(), settings.get_output_path());
diff --git a/aesxx/utils/decrypt_file.cpp b/aesxx/utils/decrypt_file.cpp
index 6419c35..811fe51 100644
--- a/aesxx/utils/decrypt_file.cpp
+++ b/aesxx/utils/decrypt_file.cpp
@@ -31,9 +31,7 @@ void decrypt_file(
 void decrypt_file(const FileSettings& settings) {
     const auto algorithm = settings.get_algorithm();
     const auto mode = settings.get_mode();
-
-    aes::Box::Key key;
-    aes::Box::parse_key(key, algorithm, settings.get_key());
+    const auto key = aes::Key::parse(settings.get_key(), algorithm);
 
     aes::Box box{algorithm, key, mode, settings.get_iv()};
     decrypt_file(box, settings.get_input_path(), settings.get_output_path());
diff --git a/aesxx/utils/encrypt_block.cpp b/aesxx/utils/encrypt_block.cpp
index 5f84922..acb9191 100644
--- a/aesxx/utils/encrypt_block.cpp
+++ b/aesxx/utils/encrypt_block.cpp
@@ -23,9 +23,7 @@ void encrypt_blocks(
     const BlockSettings::Input& input,
     bool verbose = false
 ) {
-    aes::Box::Key key;
-    aes::Box::parse_key(key, algorithm, input.get_key());
-
+    const auto key = aes::Key::parse(input.get_key(), algorithm);
     aes::Box box{algorithm, key, mode, input.get_iv(), verbose};
 
     for (const auto& plaintext : input.get_blocks()) {
diff --git a/aesxx/utils/encrypt_bmp.cpp b/aesxx/utils/encrypt_bmp.cpp
index 858755c..e140d70 100644
--- a/aesxx/utils/encrypt_bmp.cpp
+++ b/aesxx/utils/encrypt_bmp.cpp
@@ -31,9 +31,7 @@ void encrypt_bmp(
 void encrypt_bmp(const FileSettings& settings) {
     const auto algorithm = settings.get_algorithm();
     const auto mode = settings.get_mode();
-
-    aes::Box::Key key;
-    aes::Box::parse_key(key, algorithm, settings.get_key());
+    const auto key = aes::Key::parse(settings.get_key(), algorithm);
 
     aes::Box box{algorithm, key, mode, settings.get_iv()};
     encrypt_bmp(box, settings.get_input_path(), settings.get_output_path());
diff --git a/aesxx/utils/encrypt_file.cpp b/aesxx/utils/encrypt_file.cpp
index 7be07ad..c94f6ee 100644
--- a/aesxx/utils/encrypt_file.cpp
+++ b/aesxx/utils/encrypt_file.cpp
@@ -31,9 +31,7 @@ void encrypt_file(
 void encrypt_file(const FileSettings& settings) {
     const auto algorithm = settings.get_algorithm();
     const auto mode = settings.get_mode();
-
-    aes::Box::Key key;
-    aes::Box::parse_key(key, algorithm, settings.get_key());
+    const auto key = aes::Key::parse(settings.get_key(), algorithm);
 
     aes::Box box{algorithm, key, mode, settings.get_iv()};
     encrypt_file(box, settings.get_input_path(), settings.get_output_path());
-- 
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