add aes module

module/aes/aes.go

@@ -0,0 +1,57 @@
+package aes
+
+import (
+  "bytes"
+  "crypto/aes"
+  "crypto/cipher"
+  "crypto/rand"
+)
+
+// PKCS7Padding -
+func PKCS7Padding(cipherText []byte, blockSize int) []byte {
+	padding := blockSize - len(cipherText)%blockSize
+	padText := bytes.Repeat([]byte{byte(padding)}, padding)
+	return append(cipherText, padText...)
+}
+
+// PKCS7UnPadding -
+func PKCS7UnPadding (origData []byte) []byte {
+  length := len(origData)
+  unpadding := int(origData[length - 1])
+  return origData[:(length - unpadding)]
+}
+
+// Encrypt -
+func Encrypt (origData, key []byte) (enc []byte, err error) {
+  block , err := aes.NewCipher(key)
+  if err != nil {
+    return
+  }
+  blockSize := block.BlockSize()
+  origData = PKCS7Padding(origData, blockSize)
+  ivByte := make([]byte, blockSize)
+  _, err = rand.Read(ivByte)
+  if err != nil {
+    return
+  }
+  blockMode := cipher.NewCBCEncrypter(block, ivByte)
+  enc = make([]byte, len(origData))
+  blockMode.CryptBlocks(enc, origData)
+  return
+}
+
+// Decrypt -
+func Decrypt (encData, key []byte) (dec []byte, err error) {
+  block, err := aes.NewCipher(key)
+  if err != nil {
+    return
+  }
+  blockSize := block.BlockSize()
+  ivByte := encData[:blockSize]
+  encData = encData[blockSize:]
+  blockMode := cipher.NewCBCDecrypter(block, ivByte)
+  dec = make([]byte, len(encData))
+  blockMode.CryptBlocks(dec, encData)
+  dec = PKCS7UnPadding(dec)
+  return
+}