init

README.md

@@ -1,3 +1,18 @@
 # smuggler
 
-A steganography tool that abuses UTF-8 PUAs to encode messages, which can be used as subtle attacks on AI prompts
+A steganography tool that abuses UTF-8 PUAs to encode messages, which can be used for subtle attacks on AI prompts
+
+```
+user@angeltech:$ go build .
+```  
+```
+user@angeltech:$ ./smuggler encode "test"
+Encoded: 󠁴󠁥󠁳󠁴
+```  
+```
+user@angeltech:$ ./smuggler decode "<000e0074><000e0065><000e0073><000e0074>"
+Decoded: test
+```
+
+Example of interaction with Grok, for reference:
+![Example of interaction with Grok](image.png)

go.mod

@@ -0,0 +1,3 @@
+module gitea.angeltech.jp/Angel-Technologies/smuggler
+
+go 1.24.3

main.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+)
+
+const (
+	PUA_START = 0xE0000
+)
+
+func encodeHiddenMessage(message string) string {
+	var hidden strings.Builder
+	for _, char := range message {
+		hidden.WriteRune(PUA_START + char)
+	}
+	return hidden.String()
+}
+
+func decodeMixedMessage(input string) string {
+	var decoded strings.Builder
+	var hiddenBuffer strings.Builder
+	inHiddenSequence := false
+
+	for _, char := range input {
+		if char >= PUA_START && char < PUA_START+0xFFFF {
+			if !inHiddenSequence && hiddenBuffer.Len() > 0 {
+				decoded.WriteString(hiddenBuffer.String())
+				hiddenBuffer.Reset()
+			}
+			inHiddenSequence = true
+			hiddenBuffer.WriteRune(char - PUA_START)
+		} else {
+			if inHiddenSequence {
+				decoded.WriteString(hiddenBuffer.String())
+				hiddenBuffer.Reset()
+				inHiddenSequence = false
+			}
+			decoded.WriteRune(char)
+		}
+	}
+
+	if hiddenBuffer.Len() > 0 {
+		decoded.WriteString(hiddenBuffer.String())
+	}
+
+	return decoded.String()
+} 
+
+func main() {
+	if len(os.Args) < 3 {
+		fmt.Println("Usage:")
+		fmt.Println("  Encode: go run main.go encode \"secret message\"")
+		fmt.Println("  Decode: go run main.go decode \"󠁳󠁥󠁣󠁲󠁥󠁴\"")
+		os.Exit(1)
+	}
+
+	command := os.Args[1]
+	text := strings.Join(os.Args[2:], " ")
+
+	switch command {
+	case "encode":
+		hidden := encodeHiddenMessage(text)
+		fmt.Printf("Encoded: %s\n", hidden)
+	case "decode":
+		decoded := decodeMixedMessage(text)
+		fmt.Printf("Decoded: %s\n", decoded)
+	default:
+		fmt.Println("Invalid command. Use 'encode' or 'decode'.")
+		os.Exit(1)
+	}
+}