add plain text WIP

works/patch/protocol/obfhttp/encoding.go.patch

@@ -0,0 +1,63 @@
+--- /dev/null
++++ b/protocol/obfhttp/encoding.go
+@@ -0,0 +1,60 @@
++// OMV
++package obfhttp
++
++import (
++	"crypto/rand"
++	"encoding/base64"
++	"math/big"
++)
++
++// TextCodec encodes binary data to text-safe strings and generates padding in the same alphabet.
++type TextCodec interface {
++	Encode(data []byte) string
++	Decode(text string) ([]byte, error)
++	Name() string
++	GeneratePadding(length int) string
++}
++
++// Base64Codec uses standard base64 encoding.
++type Base64Codec struct{}
++
++func (c *Base64Codec) Encode(data []byte) string {
++	return base64.StdEncoding.EncodeToString(data)
++}
++
++func (c *Base64Codec) Decode(text string) ([]byte, error) {
++	return base64.StdEncoding.DecodeString(text)
++}
++
++func (c *Base64Codec) Name() string {
++	return "base64"
++}
++
++func (c *Base64Codec) GeneratePadding(length int) string {
++	if length <= 0 {
++		return ""
++	}
++	// Generate random bytes and encode to base64, then trim to desired length
++	rawLen := (length*3)/4 + 1
++	raw := make([]byte, rawLen)
++	_, _ = rand.Read(raw)
++	encoded := base64.StdEncoding.EncodeToString(raw)
++	if len(encoded) > length {
++		encoded = encoded[:length]
++	}
++	return encoded
++}
++
++func newTextCodec(name string) TextCodec {
++	switch name {
++	case "", "base64":
++		return &Base64Codec{}
++	default:
++		return &Base64Codec{}
++	}
++}
++
++func randomPaddingLength() int {
++	n, _ := rand.Int(rand.Reader, big.NewInt(128))
++	return int(n.Int64()) + 16 // 16-143 chars
++}