Reorganize directory structures

Signed-off-by: Sean Du <do4suki@gmail.com>

pkg/encrypt/aes.go

@@ -0,0 +1,48 @@
+package encrypt
+
+import (
+	"bytes"
+	"crypto/aes"
+	"crypto/cipher"
+)
+
+var (
+	iv = []byte("12345678abcdefgh")
+)
+
+func padding(plainText []byte, blockSize int) []byte {
+	n := blockSize - len(plainText)%blockSize
+	temp := bytes.Repeat([]byte{byte(n)}, n)
+	plainText = append(plainText, temp...)
+	return plainText
+}
+
+func unPadding(cipherText []byte) []byte {
+	end := cipherText[len(cipherText)-1]
+	cipherText = cipherText[:len(cipherText)-int(end)]
+	return cipherText
+}
+
+func AESCBCEncrypt(plainText []byte, key []byte) []byte {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		panic(err)
+	}
+	plainText = padding(plainText, block.BlockSize())
+	blockMode := cipher.NewCBCEncrypter(block, iv)
+	cipherText := make([]byte, len(plainText))
+	blockMode.CryptBlocks(cipherText, plainText)
+	return cipherText
+}
+
+func AESCBCDecrypt(cipherText []byte, key []byte) []byte {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		panic(err)
+	}
+	plainText := make([]byte, len(cipherText))
+	blockMode := cipher.NewCBCDecrypter(block, iv)
+	blockMode.CryptBlocks(plainText, cipherText)
+	plainText = unPadding(plainText)
+	return plainText
+}