[seraphis_wallet]: encrypted file

src/seraphis_wallet/encrypted_file.h

@@ -0,0 +1,119 @@
+#pragma once
+
+#include "crypto/chacha.h"
+#include "crypto/crypto.h"
+#include "file_io_utils.h"
+#include "serialization/binary_archive.h"
+#include "serialization/containers.h"
+#include "serialization/crypto.h"
+#include "serialization/serialization.h"
+#include "serialization/string.h"
+#include "storages/portable_storage_template_helper.h"
+#include "string_coding.h"
+
+#include <type_traits>
+
+struct EncryptedFile
+{
+    std::string encrypted_data;
+    crypto::chacha_iv iv;
+
+    BEGIN_SERIALIZE_OBJECT()
+    VERSION_FIELD(0)
+    FIELD(encrypted_data)
+    FIELD(iv)
+    END_SERIALIZE()
+};
+
+template <class T> bool read_encrypted_file(std::string path, const crypto::chacha_key &key, T &struct_out)
+{
+    std::string buf;
+    if (!epee::file_io_utils::load_file_to_string(path, buf))
+        return false;
+
+    EncryptedFile file;
+
+    binary_archive<false> file_ar{epee::strspan<std::uint8_t>(buf)};
+    if (!::serialization::serialize(file_ar, file))
+        return false;
+
+    std::string decrypted_data;
+    decrypted_data.resize(file.encrypted_data.size());
+    crypto::chacha20(file.encrypted_data.data(), file.encrypted_data.size(), key, file.iv, &decrypted_data[0]);
+
+    binary_archive<false> ar{epee::strspan<std::uint8_t>(decrypted_data)};
+
+    if (!::serialization::serialize(ar, struct_out))
+        return false;
+
+    return true;
+}
+
+// NOTE: if this were c++20, Concepts and `require` could be used to make this one function
+template <class T> bool read_encrypted_file_json(std::string path, const crypto::chacha_key &key, T &struct_out)
+{
+    std::string buf;
+    if (!epee::file_io_utils::load_file_to_string(path, buf))
+        return false;
+
+    EncryptedFile file;
+
+    binary_archive<false> file_ar{epee::strspan<std::uint8_t>(buf)};
+    if (!::serialization::serialize(file_ar, file))
+        return false;
+
+    std::string decrypted_data;
+    decrypted_data.resize(file.encrypted_data.size());
+    crypto::chacha20(file.encrypted_data.data(), file.encrypted_data.size(), key, file.iv, &decrypted_data[0]);
+
+    return epee::serialization::load_t_from_json(struct_out, decrypted_data);
+}
+
+template <class T> bool write_encrypted_file(std::string path, const crypto::chacha_key &key, T &struct_in)
+{
+    std::stringstream data_oss;
+    binary_archive<true> data_ar(data_oss);
+    if (!::serialization::serialize(data_ar, struct_in))
+        return false;
+
+    std::string buf = data_oss.str();
+
+    EncryptedFile file = {};
+    file.iv = crypto::rand<crypto::chacha_iv>();
+
+    std::string encrypted_data;
+    encrypted_data.resize(buf.size());
+
+    crypto::chacha20(std::move(buf.data()), buf.size(), key, file.iv, &encrypted_data[0]);
+
+    file.encrypted_data = encrypted_data;
+
+    std::stringstream file_oss;
+    binary_archive<true> file_ar(file_oss);
+    if (!::serialization::serialize(file_ar, file))
+        return false;
+
+    return epee::file_io_utils::save_string_to_file(path, file_oss.str());
+}
+
+template <class T> bool write_encrypted_file_json(std::string path, const crypto::chacha_key &key, T &struct_in)
+{
+    std::string struct_json = epee::serialization::store_t_to_json(struct_in);
+
+    EncryptedFile file = {};
+    file.iv = crypto::rand<crypto::chacha_iv>();
+
+    std::string encrypted_data;
+    encrypted_data.resize(struct_json.size());
+
+    crypto::chacha20(std::move(struct_json.data()), struct_json.size(), key, file.iv, &encrypted_data[0]);
+
+    file.encrypted_data = encrypted_data;
+
+    std::stringstream file_oss;
+    binary_archive<true> file_ar(file_oss);
+    if (!::serialization::serialize(file_ar, file))
+        return false;
+
+    return epee::file_io_utils::save_string_to_file(path, file_oss.str());
+}

tests/unit_tests/CMakeLists.txt

@@ -122,7 +122,8 @@ set(unit_tests_sources
   aligned.cpp
   rpc_version_str.cpp
   x25519.cpp
-  zmq_rpc.cpp)
+  zmq_rpc.cpp
+  encrypted_file.cpp)
 
 set(unit_tests_headers
   unit_tests_utils.h)

tests/unit_tests/encrypted_file.cpp

@@ -0,0 +1,55 @@
+#include <boost/filesystem.hpp>
+#include <boost/filesystem/operations.hpp>
+#include <gtest/gtest.h>
+
+#include "crypto/chacha.h"
+#include "seraphis_wallet/encrypted_file.h"
+#include "serialization/serialization.h"
+#include "serialization/keyvalue_serialization.h"
+
+struct test_s
+{
+    std::string data;
+
+    BEGIN_SERIALIZE()
+    FIELD(data)
+    END_SERIALIZE()
+
+    BEGIN_KV_SERIALIZE_MAP()
+    KV_SERIALIZE_VAL_POD_AS_BLOB_FORCE(data)
+    END_KV_SERIALIZE_MAP()
+};
+
+TEST(EncryptedFile, ReadWriteBlob)
+{
+    boost::filesystem::path temp_file = boost::filesystem::temp_directory_path() / boost::filesystem::unique_path();
+    const std::string tmp_path = temp_file.native();
+
+    test_s test{.data = "monero is awesome"};
+
+    crypto::chacha_key key;
+    crypto::generate_chacha_key("monero is double awesome", key, 1);
+
+    ASSERT_TRUE(write_encrypted_file(tmp_path, key, test));
+
+    ASSERT_TRUE(read_encrypted_file(tmp_path, key, test));
+
+    ASSERT_TRUE(test.data == "monero is awesome");
+}
+
+TEST(EncryptedFile, ReadWriteJson)
+{
+    boost::filesystem::path temp_file = boost::filesystem::temp_directory_path() / boost::filesystem::unique_path();
+    const std::string tmp_path = temp_file.native();
+
+    test_s test{.data = "monero is awesome!"};
+
+    crypto::chacha_key key;
+    crypto::generate_chacha_key("monero is double awesome", key, 1);
+
+    ASSERT_TRUE(write_encrypted_file_json(tmp_path, key, test));
+
+    ASSERT_TRUE(read_encrypted_file_json(tmp_path, key, test));
+
+    ASSERT_TRUE(test.data == "monero is awesome!");
+}