Add encryption utility functions

pkg/utils/encrypt/encrypt.go

@@ -0,0 +1,87 @@
+package encrypt
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"fmt"
+)
+
+type Encrypt struct {
+	key []byte
+}
+
+func NewEncrypt(key string) (*Encrypt, error) {
+	if len(key) < 16 {
+		return nil, errors.New("key length must be at least 16")
+	}
+
+	keyBytes := []byte(key)
+
+	return &Encrypt{key: keyBytes}, nil
+}
+
+func (e *Encrypt) Encrypt(data []byte) ([]byte, error) {
+	aesBlock, err := aes.NewCipher(e.key)
+	if err != nil {
+		return nil, err
+	}
+
+	iv := make([]byte, aesBlock.BlockSize())
+	if _, err := rand.Read(iv); err != nil {
+		return nil, err
+	}
+
+	stream := cipher.NewCFBEncrypter(aesBlock, iv)
+
+	encryptedData := make([]byte, len(data)+aesBlock.BlockSize())
+	copy(encryptedData[:aesBlock.BlockSize()], iv)
+	stream.XORKeyStream(encryptedData[aesBlock.BlockSize():], data)
+
+	return []byte(base64.StdEncoding.EncodeToString(encryptedData)), nil
+}
+
+func (e *Encrypt) Decrypt(data []byte) ([]byte, error) {
+	decodedData, err := base64.StdEncoding.DecodeString(string(data))
+	if err != nil {
+		return nil, err
+	}
+
+	aesBlock, err := aes.NewCipher(e.key)
+	if err != nil {
+		return nil, err
+	}
+
+	iv := decodedData[:aesBlock.BlockSize()]
+
+	stream := cipher.NewCFBDecrypter(aesBlock, iv)
+
+	decryptedData := make([]byte, len(decodedData)-aesBlock.BlockSize())
+	stream.XORKeyStream(decryptedData, decodedData[aesBlock.BlockSize():])
+
+	return decryptedData, nil
+}
+
+func Example() {
+	encrypt, err := NewEncrypt("my-secret-key")
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	data := []byte("This is a secret message.")
+	encryptedData, err := encrypt.Encrypt(data)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	decryptedData, err := encrypt.Decrypt(encryptedData)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	fmt.Println(string(decryptedData))
+}