feat(encrypter): Added an Encrypter. (#65)

Signed-off-by: Flc゛ <[email protected]>

encrypter/README.md

@@ -0,0 +1,18 @@
+# Encrypter
+
+## Usage
+
+```go
+package main
+
+import "github.com/go-kratos-ecosystem/components/v2/encrypter"
+
+func main() {
+	e := encrypter.New("EAFBSPAXDCIOGRUVNERQGXPYGPNKYATM")
+
+	ciphertext, _ := e.Encrypt("test")
+	plaintext, _ := e.Decrypt(ciphertext)
+
+	println(ciphertext, plaintext) // I-UVz6tds3MlRX-1afR36cLcmMw= test
+}
+```

encrypter/encrypter.go

@@ -0,0 +1,80 @@
+package encrypter
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"fmt"
+	"io"
+)
+
+type Encrypter struct {
+	key    []byte
+	cipher cipher.Block
+}
+
+func New(key string) *Encrypter {
+	return &Encrypter{
+		key: []byte(key),
+	}
+}
+
+func (e *Encrypter) Encrypt(value string) (string, error) {
+	plaintext := []byte(value)
+
+	block, err := e.getBlock()
+	if err != nil {
+		return "", err
+	}
+
+	ciphertext := make([]byte, aes.BlockSize+len(plaintext))
+	iv := ciphertext[:aes.BlockSize]
+	if _, err := io.ReadFull(rand.Reader, iv); err != nil {
+		return "", err
+	}
+
+	stream := cipher.NewCTR(block, iv)
+	stream.XORKeyStream(ciphertext[aes.BlockSize:], plaintext)
+
+	return base64.URLEncoding.EncodeToString(ciphertext), nil
+}
+
+func (e *Encrypter) Decrypt(value string) (string, error) {
+	ciphertext, err := base64.URLEncoding.DecodeString(value)
+	if err != nil {
+		return "", err
+	}
+
+	block, err := e.getBlock()
+	if err != nil {
+		return "", err
+	}
+
+	if len(ciphertext) < aes.BlockSize {
+		return "", fmt.Errorf("ciphertext too short")
+	}
+
+	iv := ciphertext[:aes.BlockSize]
+	ciphertext = ciphertext[aes.BlockSize:]
+
+	stream := cipher.NewCTR(block, iv)
+	stream.XORKeyStream(ciphertext, ciphertext)
+
+	return string(ciphertext), nil
+}
+
+func (e *Encrypter) getBlock() (cipher.Block, error) {
+	if e.cipher != nil {
+		return e.cipher, nil
+	}
+
+	c, err := aes.NewCipher(e.key)
+	if err != nil {
+		return nil, err
+	}
+
+	e.cipher = c
+
+	return c, nil
+}

encrypter/encrypter_test.go

@@ -0,0 +1,46 @@
+package encrypter
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNew(t *testing.T) {
+	assert.Equal(t, &Encrypter{
+		key: []byte("test"),
+	}, New("test"))
+}
+
+func TestEncrypter(t *testing.T) {
+	e := New("EAFBSPAXDCIOGRUVNERQGXPYGPNKYATM")
+
+	ciphertext, _ := e.Encrypt("test")
+	plaintext, _ := e.Decrypt(ciphertext)
+
+	println(ciphertext, plaintext)
+
+	assert.NotNil(t, ciphertext)
+	assert.NotNil(t, plaintext)
+	assert.Equal(t, "test", plaintext)
+}
+
+func TestEncrypter_Error(t *testing.T) {
+	e := New("test")
+
+	_, err1 := e.Encrypt("test")
+	assert.Error(t, err1)
+
+	_, err2 := e.Decrypt("test")
+	assert.Error(t, err2)
+}
+
+func TestEncrypter_Decrypt_Error(t *testing.T) {
+	e := New("EAFBSPAXDCIOGRUVNERQGXPYGPNKYATM")
+
+	_, err1 := e.Decrypt("j9_mcZXKVlInk8bbpBqJOpmDp")
+	assert.Error(t, err1)
+
+	_, err2 := e.Decrypt("MQ==")
+	assert.Error(t, err2)
+}