add pcrupto.go

pkg/utils/pcrypto/pcrypto.go

@@ -0,0 +1,87 @@
+package pcrypto
+
+import (
+	"bytes"
+	"compress/gzip"
+	"crypto/aes"
+	"crypto/cipher"
+	"encoding/base64"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io/ioutil"
+)
+
+type Pcrypto struct {
+	pkey []byte
+	paes cipher.Block
+}
+
+func (pc *Pcrypto) Init(key []byte) error {
+	var err error
+	pc.pkey = PKCS7Padding(key, aes.BlockSize)
+	pc.paes, err = aes.NewCipher(pc.pkey)
+
+	return err
+}
+
+func (pc *Pcrypto) Encrypto(src []byte) ([]byte, error) {
+	// aes
+	src = PKCS7Padding(src, aes.BlockSize)
+	blockMode := cipher.NewCBCEncrypter(pc.paes, pc.pkey)
+	crypted := make([]byte, len(src))
+	blockMode.CryptBlocks(crypted, src)
+
+	// gzip
+	var zbuf bytes.Buffer
+	zwr := gzip.NewWriter(&zbuf)
+	defer zwr.Close()
+	zwr.Write(crypted)
+	zwr.Flush()
+
+	// base64
+	return []byte(base64.StdEncoding.EncodeToString(zbuf.Bytes())), nil
+}
+
+func (pc *Pcrypto) Decrypto(str []byte) ([]byte, error) {
+	// base64
+	data, err := base64.StdEncoding.DecodeString(string(str))
+	if err != nil {
+		return nil, err
+	}
+
+	// gunzip
+	zbuf := bytes.NewBuffer(data)
+	zrd, _ := gzip.NewReader(zbuf)
+	defer zrd.Close()
+	data, _ = ioutil.ReadAll(zrd)
+
+	// aes
+	decryptText, err := hex.DecodeString(fmt.Sprintf("%x", data))
+	if err != nil {
+		return nil, err
+	}
+
+	if len(decryptText)%aes.BlockSize != 0 {
+		return nil, errors.New("crypto/cipher: ciphertext is not a multiple of the block size")
+	}
+
+	blockMode := cipher.NewCBCDecrypter(pc.paes, pc.pkey)
+
+	blockMode.CryptBlocks(decryptText, decryptText)
+	decryptText = PKCS7UnPadding(decryptText)
+
+	return decryptText, nil
+}
+
+func PKCS7Padding(ciphertext []byte, blockSize int) []byte {
+	padding := blockSize - len(ciphertext)%blockSize
+	padtext := bytes.Repeat([]byte{byte(padding)}, padding)
+	return append(ciphertext, padtext...)
+}
+
+func PKCS7UnPadding(origData []byte) []byte {
+	length := len(origData)
+	unpadding := int(origData[length-1])
+	return origData[:(length - unpadding)]
+}