From 978021293f92735c9222a9f7efb98eaa11f45e15 Mon Sep 17 00:00:00 2001
From: shazbert <oharareid.ryan@gmail.com>
Date: Fri, 3 Mar 2017 09:16:20 +1100
Subject: [PATCH] Added basic encryption service for JSON file

---
 encryption.go | 142 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 encryption.go

diff --git a/encryption.go b/encryption.go
new file mode 100644
index 00000000..098756db
--- /dev/null
+++ b/encryption.go
@@ -0,0 +1,142 @@
+package main
+
+import (
+	"bytes"
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+)
+
+const (
+	ENCRYPTION_CONFIRMATION_STRING = "THORS-HAMMER"
+)
+
+type Encryption struct {
+	CryptoKey     []byte
+	EncryptedFile []byte
+	Nonce         []byte
+	encrypPerm    bool
+	decryptPerm   bool
+}
+
+func (e *Encryption) SetUp() {
+	for len(e.CryptoKey) != 32 {
+		fmt.Println("Please enter a unique 32Char key to set up encryption: \n")
+
+		_, err := fmt.Scanln(&e.CryptoKey)
+		if err != nil {
+			panic(err)
+		}
+
+		if len(e.CryptoKey) > 32 || len(e.CryptoKey) < 32 {
+			fmt.Println("Please Re-enter a 32char key..\n")
+		}
+	}
+
+	e.Nonce = make([]byte, 12)
+	if _, err := io.ReadFull(rand.Reader, e.Nonce); err != nil {
+		panic(err)
+	}
+
+	e.encrypPerm = false
+	e.decryptPerm = false
+}
+
+func (e *Encryption) Encrypt() []byte {
+	block, err := aes.NewCipher(e.CryptoKey)
+	if err != nil {
+		panic(err)
+	}
+
+	aesgcm, err := cipher.NewGCM(block)
+	if err != nil {
+		panic(err)
+	}
+
+	configfile := e.ReadFile(CONFIG_FILE)
+
+	if e.ConfirmJSON(configfile) != true {
+		log.Println("File cannot be encrypted.\n")
+		if e.ConfirmECS(configfile) != true {
+			log.Println("File Corrupted.")
+			panic(err)
+		}
+		log.Println("File already encrypted.")
+		return configfile
+	}
+	e.EncryptedFile = aesgcm.Seal(nil, e.Nonce, configfile, nil)
+
+	appendedFile := []byte(ENCRYPTION_CONFIRMATION_STRING)
+	appendedFile = append(appendedFile, e.EncryptedFile...)
+	return appendedFile
+}
+
+func (e *Encryption) Decrypt() []byte {
+	blockDecrypt, err := aes.NewCipher(e.CryptoKey)
+	if err != nil {
+		panic(err)
+	}
+
+	aesgcmDecrypt, err := cipher.NewGCM(blockDecrypt)
+	if err != nil {
+		panic(err)
+	}
+
+	configfile := e.ReadFile(CONFIG_FILE)
+	if e.ConfirmECS(configfile) != true {
+		log.Println("File cannot be decrypted..\n")
+		if e.ConfirmJSON(configfile) != true {
+			log.Println("File corrupted.")
+			panic(err)
+		}
+		log.Println("File already decrypted.")
+		return configfile
+	}
+
+	unencryptedFile, err := aesgcmDecrypt.Open(nil, e.Nonce, e.RemoveECS(configfile), nil)
+	if err != nil {
+		log.Println("File Corrupted")
+		panic(err)
+	}
+	return unencryptedFile
+}
+
+func (e *Encryption) ReadFile(filename string) []byte {
+	file, err := ioutil.ReadFile(filename)
+	if err != nil {
+		panic(err)
+	}
+	return file
+}
+
+func (e *Encryption) SaveFile(file []byte) {
+	mode := int(0777)
+	perm := os.FileMode(mode)
+	err := ioutil.WriteFile(CONFIG_FILE, file, perm)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func (e *Encryption) ConfirmJSON(file []byte) bool {
+	err := json.Unmarshal(file, nil) //Needs Revision
+	if err != nil {
+		return true //Fix after revision
+	}
+	return true
+}
+
+func (e *Encryption) ConfirmECS(file []byte) bool {
+	subslice := []byte(ENCRYPTION_CONFIRMATION_STRING)
+	return bytes.Contains(file, subslice)
+}
+
+func (e *Encryption) RemoveECS(file []byte) []byte {
+	return bytes.Trim(file, ENCRYPTION_CONFIRMATION_STRING)
+}