code cleanup

generator/crypt.go

@@ -0,0 +1,38 @@
+package generator
+
+import (
+	"bytes"
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"io"
+)
+
+func pkcs7pad(data []byte, blockSize int) []byte {
+	padLen := blockSize - len(data)%blockSize
+	padding := bytes.Repeat([]byte{byte(padLen)}, padLen)
+	return append(data, padding...)
+}
+
+func (g *Generator) generateBaseAesEncUrl(file []byte) (string, error) {
+	c, err := aes.NewCipher(g.config.encryptionKeyBin)
+	if err != nil {
+		return "", err
+	}
+
+	data := pkcs7pad(file, aes.BlockSize)
+
+	ciphertext := make([]byte, aes.BlockSize+len(data))
+	iv := ciphertext[:aes.BlockSize]
+
+	if _, err = io.ReadFull(rand.Reader, iv); err != nil {
+		return "", err
+	}
+
+	mode := cipher.NewCBCEncrypter(c, iv)
+	mode.CryptBlocks(ciphertext[aes.BlockSize:], data)
+
+	encryptedURL := g.generateBase64Url(ciphertext)
+
+	return "enc/" + encryptedURL, nil
+}