diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 92d71e3..aa42c45 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,4 +1,4 @@
-set(SOURCES main.cpp crypto.cpp utils.cpp)
+set(SOURCES main.cpp crypto.cpp io.cpp utils.cpp)
 
 add_executable(horcrux ${SOURCES})
 add_library(${CMAKE_PROJECT_NAME}_lib STATIC ${SOURCES})
diff --git a/src/io.cpp b/src/io.cpp
new file mode 100644
index 0000000..2792955
--- /dev/null
+++ b/src/io.cpp
@@ -0,0 +1,97 @@
+#include <iostream>
+#include "io.h"
+
+namespace horcrux {
+namespace fs = std::filesystem;
+
+FsPlainInput::FsPlainInput(const std::string& path) : file_path(path)
+{
+	if (fs::status(path).type() != fs::file_type::regular){
+		throw std::invalid_argument("Input is not a regular file");
+	}
+	file_size = fs::file_size(file_path);
+	if (file_size == 0){
+		throw std::invalid_argument("Input is empty, nothing to encrypt");
+	}
+	file_stream = std::ifstream(file_path, std::ios::binary);
+}
+
+std::vector<unsigned char> FsPlainInput::read(){
+	std::vector<unsigned char> result(file_size);
+	file_stream.read(reinterpret_cast<char*>(result.data()), file_size);
+	return result;
+}
+
+FsCryptoInput::FsCryptoInput(const std::vector<std::string>& filenames)
+{
+	if (filenames.empty()){
+		throw std::invalid_argument("No files to decrypt");
+	}
+	for (auto name : filenames){
+		auto path = fs::path{name};
+		if (fs::status(path).type() != fs::file_type::regular){
+			throw std::invalid_argument("Input is not a regular file");
+		}
+		file_paths.emplace_back(path, fs::file_size(path));
+		total_size += file_paths.back().second;
+	}
+	if (total_size == 0){
+		throw std::invalid_argument("No data to decrypt");
+	}
+}
+
+std::vector<unsigned char> FsCryptoInput::read(){
+	std::vector<unsigned char> result(total_size);
+	size_t data_read{0};
+	for (auto& f : file_paths){
+		std::ifstream ifstream(f.first);
+		ifstream.read(reinterpret_cast<char*>(result.data()) + data_read, f.second);
+		data_read += f.second;
+	}
+	return result;
+}
+
+FsPlainOutput::FsPlainOutput(const std::string& filename)
+	: file_path(filename)
+{
+	if (fs::exists(file_path) && fs::status(file_path).type() != fs::file_type::regular){
+		throw std::invalid_argument("Output file is not a regular file");
+	}
+}
+size_t FsPlainOutput::write(const std::vector<unsigned char>& to_write){
+	std::ofstream out(file_path, std::ios::binary);
+	out.write(reinterpret_cast<const char*>(to_write.data()), to_write.size());
+	return to_write.size();
+}
+
+FsCryptoOutput::FsCryptoOutput(const std::string& folder, const int horcrux_num, const size_t horcrux_size = 0,
+		const std::string& filename = "horcrux")
+	: folder_path(folder), base_name(filename),
+	num(horcrux_num), size(horcrux_size)
+{
+	if (fs::status(folder_path).type() != fs::file_type::directory){
+		throw std::invalid_argument("Output is not a directory");
+	}
+
+	if (horcrux_num <= 0){
+		throw std::invalid_argument("Invalid horcrux num");
+	}
+}
+
+size_t FsCryptoOutput::write(const std::vector<unsigned char>& to_write){
+	size = to_write.size() / num;
+	std::ofstream f;
+	created_files.clear();
+	size_t data_written{0};
+	for (int i = 0; i < num; ++i){
+		std::string name = base_name + '_' + std::to_string(i) + ".enc";
+		created_files.emplace_back(folder_path / name);
+		f = std::ofstream(created_files.back(),
+				std::ios::binary | std::ios::trunc);
+		auto chunk_size = i + 1 != num ? size : size + to_write.size() % size;
+		f.write(reinterpret_cast<const char*>(to_write.data()) + data_written, chunk_size);
+		data_written += chunk_size;
+	}
+	return data_written;
+}
+};
diff --git a/src/io.h b/src/io.h
new file mode 100644
index 0000000..e92ea35
--- /dev/null
+++ b/src/io.h
@@ -0,0 +1,47 @@
+#include <string>
+#include <filesystem>
+#include <fstream>
+#include <vector>
+
+namespace horcrux {
+
+class FsPlainInput {
+	std::filesystem::path file_path;
+	size_t file_size;
+	std::ifstream file_stream;
+
+public:
+	FsPlainInput(const std::string& path);
+	std::vector<unsigned char> read();
+};
+
+class FsCryptoInput {
+	std::vector<std::pair<std::filesystem::path, size_t>> file_paths;
+	size_t total_size{0};
+
+public:
+	FsCryptoInput(const std::vector<std::string>& filenames);
+	std::vector<unsigned char> read();
+};
+
+class FsPlainOutput {
+	std::filesystem::path file_path;
+
+public:
+	FsPlainOutput(const std::string& filename);
+	size_t write(const std::vector<unsigned char>& to_write);
+};
+
+class FsCryptoOutput {
+	std::filesystem::path folder_path;
+	std::string base_name;
+	int num;
+	size_t size;
+
+public:
+	std::vector<std::filesystem::path> created_files;
+
+	FsCryptoOutput(const std::string& folder, const int horcrux_num, const size_t horcrux_size, const std::string& filename);
+	size_t write(const std::vector<unsigned char>& to_write);
+};
+};
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 3b7474f..b954fe4 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -1,7 +1,11 @@
 set(BINARY ${CMAKE_PROJECT_NAME}_test)
 
-add_executable(${BINARY} main.cpp crypto-test.cpp utils-test.cpp)
+add_executable(${BINARY} main.cpp crypto-test.cpp io-test.cpp utils-test.cpp)
 
 add_test(NAME test COMMAND ${BINARY})
 
 target_link_libraries(${BINARY} PUBLIC ${CMAKE_PROJECT_NAME}_lib gtest)
+
+file(COPY ${CMAKE_CURRENT_SOURCE_DIR}/test_work_dir
+	 DESTINATION ${CMAKE_BINARY_DIR})
+add_definitions(-DTEST_WORK_DIR="${CMAKE_BINARY_DIR}/test_work_dir")
diff --git a/test/io-test.cpp b/test/io-test.cpp
new file mode 100644
index 0000000..1d20bf0
--- /dev/null
+++ b/test/io-test.cpp
@@ -0,0 +1,126 @@
+#include "gtest/gtest.h"
+#include "io.cpp"
+
+#ifndef TEST_WORK_DIR
+#error Please define TEST_WORK_DIR
+#endif
+
+const std::string folder{TEST_WORK_DIR};
+const std::string noexist{TEST_WORK_DIR "/nope"};
+const std::string empty{TEST_WORK_DIR "/empty"};
+const std::string text{TEST_WORK_DIR "/test.txt"};
+const std::string image{TEST_WORK_DIR "/mangoni.jpg"};
+
+static std::vector<unsigned char> generic_read_file(const std::string& filename){
+	auto ifstream = std::ifstream{filename, std::ios::binary};
+	auto path = std::filesystem::path{filename};
+	auto size = std::filesystem::file_size(path);
+	std::vector<unsigned char> buf(size);
+	ifstream.read(reinterpret_cast<char*>(buf.data()), size);
+	return buf;
+}
+
+TEST(IoTests, FsPlainInput) {
+	EXPECT_THROW(horcrux::FsPlainInput input{noexist}, std::invalid_argument);
+	EXPECT_THROW(horcrux::FsPlainInput input{folder}, std::invalid_argument);
+	EXPECT_THROW(horcrux::FsPlainInput input{empty}, std::invalid_argument);
+	EXPECT_NO_THROW(horcrux::FsPlainInput input{text});
+	EXPECT_NO_THROW(horcrux::FsPlainInput input{image});
+}
+
+TEST(IoTests, FsPlainInputReadText) {
+	auto input = horcrux::FsPlainInput{text};
+	auto buf = generic_read_file(text);
+	EXPECT_EQ(buf, input.read());
+}
+
+TEST(IoTests, FsPlainInputReadImg) {
+	auto input = horcrux::FsPlainInput{image};
+	auto buf = generic_read_file(image);
+	EXPECT_EQ(buf, input.read());
+}
+
+TEST(IoTests, FsCryptoOutput) {
+	EXPECT_THROW(horcrux::FsCryptoOutput output(noexist, 1), std::invalid_argument);
+	EXPECT_NO_THROW(horcrux::FsCryptoOutput output(folder, 1));
+	EXPECT_THROW(horcrux::FsCryptoOutput output(folder, 0), std::invalid_argument);
+	EXPECT_THROW(horcrux::FsCryptoOutput output(empty, 1), std::invalid_argument);
+	EXPECT_THROW(horcrux::FsCryptoOutput output(text, 1), std::invalid_argument);
+	EXPECT_THROW(horcrux::FsCryptoOutput output(image, 1), std::invalid_argument);
+}
+
+TEST(IoTests, FsCryptoOutputWriteImage){
+	auto ifstream = std::ifstream{image, std::ios::binary};
+	auto buf = generic_read_file(image);
+
+	horcrux::FsCryptoOutput out(folder, 10);
+	auto written = out.write(buf);
+	EXPECT_EQ(written, buf.size());
+
+	EXPECT_EQ(10, out.created_files.size());
+	for_each(out.created_files.begin(), out.created_files.end(),
+			[](auto f){std::filesystem::remove(f);});
+}
+
+TEST(IoTests, FsCryptoOutputWriteText){
+	auto buf = generic_read_file(text);
+
+	horcrux::FsCryptoOutput out(folder, 2);
+	auto written = out.write(buf);
+	EXPECT_EQ(written, buf.size());
+
+	EXPECT_EQ(2, out.created_files.size());
+	for_each(out.created_files.begin(), out.created_files.end(),
+			[](auto f){std::filesystem::remove(f);});
+}
+
+TEST(IoTest, FsCryptoInput){
+	EXPECT_THROW(horcrux::FsCryptoInput output({noexist, text, image}), std::invalid_argument);
+	EXPECT_THROW(horcrux::FsCryptoInput output({folder, text, image}), std::invalid_argument);
+	EXPECT_THROW(horcrux::FsCryptoInput output({}), std::invalid_argument);
+	EXPECT_THROW(horcrux::FsCryptoInput output({empty}), std::invalid_argument);
+	EXPECT_THROW(horcrux::FsCryptoInput output({empty, empty}), std::invalid_argument);
+	EXPECT_NO_THROW(horcrux::FsCryptoInput output({empty, empty, text}));
+	EXPECT_NO_THROW(horcrux::FsCryptoInput output({image, empty, text}));
+}
+
+TEST(IoTest, FsCryptoInputImage){
+	auto buf = generic_read_file(image);
+	//split image using FsCryptoOutput
+	auto out = horcrux::FsCryptoOutput(folder, 7);
+	auto written = out.write(buf);
+	EXPECT_EQ(written, buf.size());
+
+	std::vector<std::string> files;
+	transform(out.created_files.begin(), out.created_files.end(),std::back_inserter(files), [](auto p){return p.string();});
+	auto in = horcrux::FsCryptoInput(files);
+	auto read = in.read();
+	EXPECT_EQ(read, buf);
+
+	files.push_back(text);
+	in = horcrux::FsCryptoInput(files);
+	read = in.read();
+	EXPECT_NE(read, buf);
+
+	for_each(out.created_files.begin(), out.created_files.end(),
+			[](auto f){std::filesystem::remove(f);});
+}
+
+TEST(IoTest, FsPlainOuput){
+
+	EXPECT_NO_THROW(horcrux::FsPlainOutput output{noexist});
+	EXPECT_THROW(horcrux::FsPlainOutput output{folder}, std::invalid_argument);
+	EXPECT_NO_THROW(horcrux::FsPlainOutput output{empty});
+	EXPECT_NO_THROW(horcrux::FsPlainOutput output{text});
+	EXPECT_NO_THROW(horcrux::FsPlainOutput output{image});
+}
+
+TEST(IoTest, FsPlainOutputWrite){
+	auto buf = generic_read_file(image);
+	auto out = horcrux::FsPlainOutput(noexist);
+	auto written = out.write(buf);
+	EXPECT_EQ(written, buf.size());
+	auto buf2 = generic_read_file(noexist);
+	EXPECT_EQ(buf, buf2);
+	std::filesystem::remove(noexist);
+}
diff --git a/test/test_work_dir/empty b/test/test_work_dir/empty
new file mode 100644
index 0000000..e69de29
diff --git a/test/test_work_dir/mangoni.jpg b/test/test_work_dir/mangoni.jpg
new file mode 100644
index 0000000..5aebcec
Binary files /dev/null and b/test/test_work_dir/mangoni.jpg differ
diff --git a/test/test_work_dir/test.txt b/test/test_work_dir/test.txt
new file mode 100644
index 0000000..57528e3
--- /dev/null
+++ b/test/test_work_dir/test.txt
@@ -0,0 +1,28 @@
+What's your name Catalogna
+What's your name Catalogna
+What's your name Catalogna
+What's your name Catalogna
+Cara non so perché ma quando io ti vedo mi vien da vomitare
+Forse sara' perché tu mangi troppa catalogna, catalogna
+Catalogna catalogna cata cata cata cata catalogna
+Catalogna catalogna e nessun altro tipo di verdura cotta.
+Sono andato in un centro di allevamento di cinghiali in Lunigiana
+E ti ho comprato un cinghialino, l'ho arrostito e l'ho riempito
+Con un tacchino di terra cotta ripieno di un piccione vivo con il verme
+In bocca, ho arrostito tutto insieme te l'ho portato, oh, non l'hai
+Mangiato eri immersa in una vasca di catalogna. Non si fa cosi'!
+Catalogna catalogna cata cata cata cata catalogna
+Catalogna catalogna cata cata cata cata catalogna
+Non puoi mangiare solo catalogna
+E' una dieta costituita da un elemento solo
+Non mi puoi far credere che questo sia sufficiente
+Alla tua corretta crescita, perdi i capelli,
+Non puoi vivere mangiando solo catalogna,
+Non mi puoi convincere di questo fatto.
+Ehi... ma... no... amore ma... solo ora invece capisco
+Che la catalogna effettivamente ci permette di condurre
+Una vita psichicamente corretta e anche sessualmente
+Fantastica! Si', ho capito, infilami la catalogna nel culo,
+Voglio fare all'amore con te, infilamela nei capezzoli,
+Voglio godere tantissimo!...
+Siamo cresciuti mangiando verdura voglio morire con te