initial commit

utils/utils.go

@@ -0,0 +1,80 @@
+package utils
+
+import (
+	"bytes"
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/md5"
+	"crypto/rand"
+	"encoding/hex"
+	"errors"
+	jsoniter "github.com/json-iterator/go"
+)
+
+var (
+	ErrUnsupported        = errors.New(`unsupported operation`)
+	ErrEntityInvalid      = errors.New(`entity is not valid`)
+	ErrFailedVerification = errors.New(`failed to verify entity`)
+	JSON                  = jsoniter.ConfigCompatibleWithStandardLibrary
+)
+func GenRandByte(n int) []byte {
+	secBuffer := make([]byte, n)
+	rand.Reader.Read(secBuffer)
+	return secBuffer
+}
+
+func GetStrUUID() string {
+	return hex.EncodeToString(GenRandByte(16))
+}
+
+func GetUUID() []byte {
+	return GenRandByte(16)
+}
+
+func GetMD5(data []byte) ([]byte, string) {
+	hash := md5.New()
+	hash.Write(data)
+	result := hash.Sum(nil)
+	return result, hex.EncodeToString(result)
+}
+
+func Encrypt(data []byte, key []byte) ([]byte, error) {
+	//fmt.Println(`Send: `, string(data))
+
+	nonce := make([]byte, 64)
+	rand.Reader.Read(nonce)
+	data = append(data, nonce...)
+
+	hash, _ := GetMD5(data)
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	stream := cipher.NewCTR(block, hash)
+	encBuffer := make([]byte, len(data))
+	stream.XORKeyStream(encBuffer, data)
+	return append(hash, encBuffer...), nil
+}
+
+func Decrypt(data []byte, key []byte) ([]byte, error) {
+	// MD5[16 bytes] + Data[n bytes] + Nonce[64 bytes]
+	dataLen := len(data)
+	if dataLen <= 16+64 {
+		return nil, ErrEntityInvalid
+	}
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	stream := cipher.NewCTR(block, data[:16])
+	decBuffer := make([]byte, dataLen-16)
+	stream.XORKeyStream(decBuffer, data[16:])
+
+	hash, _ := GetMD5(decBuffer)
+	if !bytes.Equal(hash, data[:16]) {
+		return nil, ErrFailedVerification
+	}
+
+	//fmt.Println(`Recv: `, string(decBuffer[:dataLen-16-64]))
+	return decBuffer[:dataLen-16-64], nil
+}