From 6ff4e9c0622dee2663d70059594e58b3c96f135a Mon Sep 17 00:00:00 2001
From: Rose Hogenson <rosehogenson@posteo.net>
Date: Sat, 4 Oct 2025 21:17:49 -0700
Subject: Add some extra methods to oae2

---
 internal/cryptoutil/oae2.go | 134 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 127 insertions(+), 7 deletions(-)

diff --git a/internal/cryptoutil/oae2.go b/internal/cryptoutil/oae2.go
index 4997051..be4f1a9 100644
--- a/internal/cryptoutil/oae2.go
+++ b/internal/cryptoutil/oae2.go
@@ -11,6 +11,7 @@ import (
 	"encoding/binary"
 	"errors"
 	"io"
+	"strings"
 )
 
 // Online Authenticated Encryption from https://eprint.iacr.org/2015/189.pdf
@@ -153,6 +154,18 @@ func (w *EncryptingWriter) initialize() error {
 	return w.err
 }
 
+func (w *EncryptingWriter) writeBuf() error {
+	var encrypted []byte
+	if encrypted, w.err = w.oae2.encryptBlock(w.buf[:0], w.buf, false); w.err != nil {
+		return w.err
+	}
+	if _, w.err = w.w.Write(encrypted); w.err != nil {
+		return w.err
+	}
+	w.buf = w.buf[:0]
+	return nil
+}
+
 func (w *EncryptingWriter) Write(buf []byte) (int, error) {
 	if !w.initialized {
 		if err := w.initialize(); err != nil {
@@ -166,14 +179,9 @@ func (w *EncryptingWriter) Write(buf []byte) (int, error) {
 	nn := 0
 	for r.Len() > 0 {
 		if len(w.buf) == w.segmentSize {
-			var encrypted []byte
-			if encrypted, w.err = w.oae2.encryptBlock(w.buf[:0], w.buf, false); w.err != nil {
-				return nn, w.err
+			if err := w.writeBuf(); err != nil {
+				return nn, err
 			}
-			if _, w.err = w.w.Write(encrypted); w.err != nil {
-				return nn, w.err
-			}
-			w.buf = w.buf[:0]
 		}
 		n, _ := r.Read(w.buf[len(w.buf):w.segmentSize])
 		w.buf = w.buf[:len(w.buf)+n]
@@ -209,6 +217,77 @@ func (w *EncryptingWriter) Close() error {
 	return nil
 }
 
+func (w *EncryptingWriter) ReadFrom(r io.Reader) (int64, error) {
+	if !w.initialized {
+		if err := w.initialize(); err != nil {
+			return 0, err
+		}
+	}
+	if w.err != nil {
+		return 0, w.err
+	}
+	var nn int64
+	bufReader := bufio.NewReaderSize(r, 1)
+	for {
+		if _, err := bufReader.Peek(1); err != nil {
+			if err == io.EOF {
+				return nn, nil
+			}
+			return nn, err
+		}
+		if len(w.buf) == w.segmentSize {
+			if err := w.writeBuf(); err != nil {
+				return nn, err
+			}
+		}
+		n, _ := io.ReadFull(bufReader, w.buf[len(w.buf):w.segmentSize])
+		w.buf = w.buf[:len(w.buf)+n]
+		nn += int64(n)
+	}
+}
+
+func (w *EncryptingWriter) WriteByte(c byte) error {
+	if !w.initialized {
+		if err := w.initialize(); err != nil {
+			return err
+		}
+	}
+	if w.err != nil {
+		return w.err
+	}
+	if len(w.buf) == w.segmentSize {
+		if err := w.writeBuf(); err != nil {
+			return err
+		}
+	}
+	w.buf = append(w.buf, c)
+	return nil
+}
+
+func (w *EncryptingWriter) WriteString(s string) (int, error) {
+	if !w.initialized {
+		if err := w.initialize(); err != nil {
+			return 0, err
+		}
+	}
+	if w.err != nil {
+		return 0, w.err
+	}
+	r := strings.NewReader(s)
+	nn := 0
+	for r.Len() > 0 {
+		if len(w.buf) == w.segmentSize {
+			if err := w.writeBuf(); err != nil {
+				return nn, err
+			}
+		}
+		n, _ := r.Read(w.buf[len(w.buf):w.segmentSize])
+		w.buf = w.buf[:len(w.buf)+n]
+		nn += n
+	}
+	return nn, nil
+}
+
 // A DecryptingReader decrypts data using the STREAM construction.
 type DecryptingReader struct {
 	r           *bufio.Reader
@@ -287,3 +366,44 @@ func (r *DecryptingReader) Read(buf []byte) (int, error) {
 	n, _ := r.buf.Read(buf)
 	return n, nil
 }
+
+func (r *DecryptingReader) WriteTo(w io.Writer) (int64, error) {
+	if !r.initialized {
+		if err := r.initialize(); err != nil {
+			return 0, err
+		}
+	}
+	var nn int64
+	if r.buf.Len() > 0 {
+		n, err := w.Write(r.buf.Bytes())
+		nn += int64(n)
+		if err != nil {
+			return nn, err
+		}
+	}
+	for {
+		if err := r.fillBuf(); err != nil {
+			return nn, err
+		}
+		n, err := w.Write(r.buf.Bytes())
+		nn += int64(n)
+		if err != nil {
+			return nn, err
+		}
+	}
+}
+
+func (r *DecryptingReader) ReadByte() (byte, error) {
+	if !r.initialized {
+		if err := r.initialize(); err != nil {
+			return 0, err
+		}
+	}
+	if r.buf.Len() == 0 {
+		if err := r.fillBuf(); err != nil {
+			return 0, err
+		}
+	}
+	b, _ := r.buf.ReadByte()
+	return b, nil
+}
-- 
cgit v1.3.1