add ability to encrypt working directory

crypt.go

@@ -0,0 +1,179 @@
+package main
+
+// tar.xz the entire working directory
+// and then delete the working directory
+// and then encrypt the tarball with a password
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"strings"
+
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+
+	"github.com/mholt/archiver"
+	"golang.org/x/crypto/scrypt"
+	tbget "i2pgit.org/idk/i2p.plugins.tor-manager/get"
+)
+
+func DecryptTarXZifThere(source, password string) error {
+	if tbget.FileExists(source + ".tar.xz.crypt") {
+		return DecryptTarXzip(source, password)
+	}
+	return nil
+}
+
+func TarXzip(source string) error {
+	target := fmt.Sprintf("%s.tar.xz", source)
+	txz := archiver.NewTarXz()
+	//	txz.CompressionLevel = 12
+	err := txz.Archive([]string{source}, target)
+	if err != nil {
+		return fmt.Errorf("TarGzip: TarGz() failed: %s", err.Error())
+	}
+	return nil
+}
+
+func EncryptTarXZip(source, password string) error {
+	err := TarXzip(source)
+	if err != nil {
+		return err
+	}
+	sourceBytes, err := ioutil.ReadFile(source + ".tar.xz")
+	if err != nil {
+		return err
+	}
+	encryptedSourceBytes, err := Encrypt([]byte(password), sourceBytes)
+	if err != nil {
+		return err
+	}
+	err = ioutil.WriteFile(source+".tar.xz.crypt", encryptedSourceBytes, 0644)
+	if err != nil {
+		return err
+	}
+	file, err := os.OpenFile(source+".tar.xz", os.O_RDWR, 0)
+	if err != nil {
+		log.Println("Error:", err)
+	}
+	info, err := file.Stat()
+	if err != nil {
+		log.Println("Error:", err)
+	}
+	bytes := info.Size()
+	file.Truncate(0)
+	file.Write(make([]byte, bytes))
+	file.Close()
+	os.Remove(source + ".tar.xz")
+	return nil
+}
+
+func UnTarXzip(source string) error {
+	target := strings.Replace(source, ".tar.xz", "", 1)
+	txz := archiver.NewTarXz()
+	txz.Tar.OverwriteExisting = true
+	txz.Tar.ContinueOnError = true
+	err := txz.Unarchive(source, target)
+	if err != nil {
+		return fmt.Errorf("TarGzip: Unarchive() failed: %s", err.Error())
+	}
+	return nil
+}
+
+func DecryptTarXzip(source, password string) error {
+	sourceBytes, err := ioutil.ReadFile(source + ".tar.xz.crypt")
+	if err != nil {
+		return err
+	}
+	decryptedSourceBytes, err := Decrypt([]byte(password), sourceBytes)
+	if err != nil {
+		return err
+	}
+	err = ioutil.WriteFile(source+"tar.xz", decryptedSourceBytes, 0644)
+	if err != nil {
+		return err
+	}
+	err = UnTarXzip(source + "tar.xz")
+	if err != nil {
+		return err
+	}
+	os.Remove(source + "tar.xz.crypt")
+	return nil
+}
+
+// Borrowing **VERY** heavily from: https://bruinsslot.jp/post/golang-crypto/
+
+func Encrypt(key, data []byte) ([]byte, error) {
+	key, salt, err := DeriveKey(key, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	blockCipher, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	gcm, err := cipher.NewGCM(blockCipher)
+	if err != nil {
+		return nil, err
+	}
+
+	nonce := make([]byte, gcm.NonceSize())
+	if _, err = rand.Read(nonce); err != nil {
+		return nil, err
+	}
+
+	ciphertext := gcm.Seal(nonce, nonce, data, nil)
+
+	ciphertext = append(ciphertext, salt...)
+
+	return ciphertext, nil
+}
+
+func Decrypt(key, data []byte) ([]byte, error) {
+	salt, data := data[len(data)-32:], data[:len(data)-32]
+
+	key, _, err := DeriveKey(key, salt)
+	if err != nil {
+		return nil, err
+	}
+
+	blockCipher, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	gcm, err := cipher.NewGCM(blockCipher)
+	if err != nil {
+		return nil, err
+	}
+
+	nonce, ciphertext := data[:gcm.NonceSize()], data[gcm.NonceSize():]
+
+	plaintext, err := gcm.Open(nil, nonce, ciphertext, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return plaintext, nil
+}
+
+func DeriveKey(password, salt []byte) ([]byte, []byte, error) {
+	if salt == nil {
+		salt = make([]byte, 32)
+		if _, err := rand.Read(salt); err != nil {
+			return nil, nil, err
+		}
+	}
+
+	key, err := scrypt.Key(password, salt, 1048576, 8, 1, 32)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return key, salt, nil
+}