Adding encryption package to encrypt email

internal/cards/encryption/encryption.go

@@ -0,0 +1,54 @@
+package encryption
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"io"
+)
+
+type Encryption struct {
+	Key []byte
+}
+
+func (e *Encryption) Encrypt(text string) (string, error) {
+	plaintext := []byte(text)
+
+	block, err := aes.NewCipher(e.Key)
+	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.NewCFBEncrypter(block, iv)
+	stream.XORKeyStream(cipherText[aes.BlockSize:], plaintext)
+
+	return base64.URLEncoding.EncodeToString(cipherText), nil
+}
+
+func (e *Encryption) Decrypt(cryptoText string) (string, error) {
+	cipherText, _ := base64.URLEncoding.DecodeString(cryptoText)
+
+	block, err := aes.NewCipher(e.Key)
+	if err != nil {
+		return "", err
+	}
+
+	if len(cipherText) < aes.BlockSize {
+		return "", err
+	}
+
+	iv := cipherText[:aes.BlockSize]
+	cipherText = cipherText[aes.BlockSize:]
+
+	stream := cipher.NewCFBDecrypter(block, iv)
+	stream.XORKeyStream(cipherText, cipherText)
+
+	return string(cipherText), nil
+}