X25ZYZWm

1type Encoder struct {
2	Block     cipher.Block
3	SecretKey string
4}
5
6func (e *Encoder) Encode(message string) (string, error) {
7	plainText := []byte(message)
8	cipherText := make([]byte, aes.BlockSize+len(plainText))
9	iv := cipherText[:aes.BlockSize]
10	if _, err := io.ReadFull(rand.Reader, iv); err != nil {
11		return "", nil
12	}
13	stream := cipher.NewCFBEncrypter(e.Block, iv)
14	stream.XORKeyStream(cipherText[aes.BlockSize:], plainText)
15	encodedMessage := base64.URLEncoding.EncodeToString(cipherText)
16	return encodedMessage, nil
17}
18
19func (e *Encoder) Decode(message string) (string, error) {
20	cipherText, err := base64.URLEncoding.DecodeString(message)
21	if err != nil {
22		return "", nil
23	}
24	if len(cipherText) < aes.BlockSize {
25		return "", errors.New("block size is too short")
26	}
27	iv := cipherText[:aes.BlockSize]
28	cipherText = cipherText[aes.BlockSize:]
29	stream := cipher.NewCFBDecrypter(e.Block, iv)
30	stream.XORKeyStream(cipherText, cipherText)
31	return string(cipherText), nil
32}
33
34func NewEncoder(SecretKey string) (*Encoder, error) {
35	block, err := aes.NewCipher([]byte(SecretKey))
36	if err != nil {
37		return nil, err
38	}
39	return &Encoder{
40		SecretKey: SecretKey,
41		Block:     block,
42	}, nil
43}