v0.0.65

cryptext/aes.go

@@ -0,0 +1,47 @@
+package cryptext
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"io"
+)
+
+// https://stackoverflow.com/a/18819040/1761622
+
+func EncryptAES(key, text []byte) ([]byte, error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	b := base64.StdEncoding.EncodeToString(text)
+	ciphertext := make([]byte, aes.BlockSize+len(b))
+	iv := ciphertext[:aes.BlockSize]
+	if _, err := io.ReadFull(rand.Reader, iv); err != nil {
+		return nil, err
+	}
+	cfb := cipher.NewCFBEncrypter(block, iv)
+	cfb.XORKeyStream(ciphertext[aes.BlockSize:], []byte(b))
+	return ciphertext, nil
+}
+
+func DecryptAES(key, text []byte) ([]byte, error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	if len(text) < aes.BlockSize {
+		return nil, errors.New("ciphertext too short")
+	}
+	iv := text[:aes.BlockSize]
+	text = text[aes.BlockSize:]
+	cfb := cipher.NewCFBDecrypter(block, iv)
+	cfb.XORKeyStream(text, text)
+	data, err := base64.StdEncoding.DecodeString(string(text))
+	if err != nil {
+		return nil, err
+	}
+	return data, nil
+}