""" PSBT Steganography Module - Privacy-Preserving Verification Encodes PSBT data in images for trustless verification without exposing raw data """ import json import hashlib import base64 import datetime import re import math from typing import Dict, List, Optional, Any, Union class PSBTSteganography: """ Advanced steganographic encoding for PSBT data. Enables private verification of Bitcoin transactions. """ def __init__(self): self.encoding_version = "1.0" self.default_key = "starlight_psbt_2024_secure" self.encoding_registry = {} self.supported_formats = ["png", "jpg", "webp", "bmp"] def encode_psbt_to_image(self, psbt_data: str, image_data: str, encryption_key: str = None) -> Dict[str, Any]: """ Encode PSBT data into image using LSB steganography. Maintains privacy while enabling verification. """ try: key = encryption_key or self.default_key if not self._validate_psbt_data(psbt_data): return { "success": False, "error": "Invalid PSBT data format", "timestamp": datetime.datetime.now().isoformat() } if not self._validate_image_data(image_data): return { "success": False, "error": "Invalid image data format", "timestamp": datetime.datetime.now().isoformat() } psbt_hash = hashlib.sha256(psbt_data.encode()).hexdigest() encoded_payload = self._create_steganographic_payload(psbt_data, key) encoded_image = self._apply_lsb_encoding(image_data, encoded_payload) encoding_record = { "encoding_id": hashlib.sha256(f"{psbt_hash}{datetime.datetime.now().isoformat()}".encode()).hexdigest()[:16], "psbt_hash": psbt_hash, "encoding_timestamp": datetime.datetime.now().isoformat(), "data_size": len(psbt_data), "encoding_key": hashlib.sha256(key.encode()).hexdigest(), "encoding_version": self.encoding_version, "verification_hash": hashlib.sha256(encoded_payload.encode()).hexdigest() } self.encoding_registry[encoding_record["encoding_id"]] = encoding_record return { "success": True, "encoded_image": encoded_image, "encoding_record": encoding_record, "psbt_hash": psbt_hash, "payload_size": len(encoded_payload), "encoding_method": "lsb_steganography", "timestamp": datetime.datetime.now().isoformat() } except Exception as e: return { "success": False, "error": str(e), "timestamp": datetime.datetime.now().isoformat() } def decode_psbt_from_image(self, encoded_image: str, encryption_key: str = None, encoding_id: str = None) -> Dict[str, Any]: """ Decode PSBT data from steganographically encoded image. """ try: key = encryption_key or self.default_key extracted_payload = self._extract_lsb_payload(encoded_image) decoded_data = self._decode_steganographic_payload(extracted_payload, key) if not self._validate_psbt_data(decoded_data): return { "success": False, "error": "Decoded data is not valid PSBT format", "timestamp": datetime.datetime.now().isoformat() } psbt_hash = hashlib.sha256(decoded_data.encode()).hexdigest() verification_result = { "success": True, "psbt_data": decoded_data, "psbt_hash": psbt_hash, "decoding_timestamp": datetime.datetime.now().isoformat(), "verification_ready": True } if encoding_id and encoding_id in self.encoding_registry: original_record = self.encoding_registry[encoding_id] verification_result["encoding_verified"] = original_record["psbt_hash"] == psbt_hash verification_result["original_encoding"] = original_record return verification_result except Exception as e: return { "success": False, "error": str(e), "timestamp": datetime.datetime.now().isoformat() } def _validate_psbt_data(self, psbt_data: str) -> bool: """Validate PSBT data format.""" if not psbt_data or len(psbt_data) < 10: return False psbt_indicators = ["psbt", "unsigned", "transaction", "input", "output"] indicator_count = sum(1 for indicator in psbt_indicators if indicator.lower() in psbt_data.lower()) return indicator_count >= 2 or len(psbt_data) > 100 def _validate_image_data(self, image_data: str) -> bool: """Validate image data format.""" if not image_data or len(image_data) < 10: return False image_headers = ["PNG", "JFIF", "GIF", "WEBP", "BM", "HEADER", "IMAGE"] return any(header in image_data.upper() for header in image_headers) def _create_steganographic_payload(self, psbt_data: str, key: str) -> str: """ Create steganographic payload with metadata. """ timestamp = str(int(datetime.datetime.now().timestamp())) data_hash = hashlib.sha256(psbt_data.encode()).hexdigest() payload_components = [ "STARLIGHT", # Magic bytes self.encoding_version, timestamp, data_hash, psbt_data, hashlib.sha256(key.encode()).hexdigest()[:16] ] payload = "|".join(payload_components) payload_with_checksum = payload + "|" + hashlib.sha256(payload.encode()).hexdigest()[:8] return base64.b64encode(payload_with_checksum.encode()).decode() def _apply_lsb_encoding(self, image_data: str, payload: str) -> str: """ Apply LSB (Least Significant Bit) encoding to image data. Simulated implementation for demonstration. """ binary_payload = ''.join(format(ord(char), '08b') for char in payload) binary_payload += '1111111111111110' # End marker image_binary = ''.join(format(ord(char), '08b') for char in image_data) if len(binary_payload) > len(image_binary): binary_payload = binary_payload[:len(image_binary) - 16] encoded_binary = list(image_binary) payload_index = 0 for i in range(len(encoded_binary)): if payload_index < len(binary_payload): encoded_binary[i] = encoded_binary[i][:-1] + binary_payload[payload_index] payload_index += 1 else: break encoded_chars = [] for i in range(0, len(encoded_binary), 8): byte = ''.join(encoded_binary[i:i+8]) if len(byte) == 8: encoded_chars.append(chr(int(byte, 2))) return ''.join(encoded_chars) def _extract_lsb_payload(self, encoded_image: str) -> str: """ Extract LSB payload from encoded image. """ image_binary = ''.join(format(ord(char), '08b') for char in encoded_image) extracted_bits = [] for i in range(len(image_binary)): extracted_bits.append(image_binary[i][-1]) binary_payload = ''.join(extracted_bits) end_marker = binary_payload.find('1111111111111110') if end_marker != -1: binary_payload = binary_payload[:end_marker] payload_bytes = [] for i in range(0, len(binary_payload), 8): byte = binary_payload[i:i+8] if len(byte) == 8: payload_bytes.append(chr(int(byte, 2))) try: return base64.b64decode(''.join(payload_bytes)).decode() except: return '' def _decode_steganographic_payload(self, payload: str, key: str) -> str: """ Decode steganographic payload and validate integrity. """ try: components = payload.split('|') if len(components) < 6: raise ValueError("Invalid payload structure") magic = components[0] version = components[1] timestamp = components[2] data_hash = components[3] psbt_data = components[4] key_hash = components[5] checksum = components[6] if len(components) > 6 else "" if magic != "STARLIGHT": raise ValueError("Invalid magic bytes") expected_key_hash = hashlib.sha256(key.encode()).hexdigest()[:16] if key_hash != expected_key_hash: raise ValueError("Invalid encryption key") payload_without_checksum = '|'.join(components[:-1]) if checksum else payload expected_checksum = hashlib.sha256(payload_without_checksum.encode()).hexdigest()[:8] if checksum and checksum != expected_checksum: raise ValueError("Payload checksum mismatch") actual_data_hash = hashlib.sha256(psbt_data.encode()).hexdigest() if data_hash != actual_data_hash: raise ValueError("PSBT data integrity check failed") return psbt_data except Exception as e: raise ValueError(f"Payload decoding failed: {str(e)}") def create_verification_hash(self, psbt_data: str, image_data: str, additional_context: str = "") -> str: """ Create verification hash for PSBT without exposing full data. """ psbt_hash = hashlib.sha256(psbt_data.encode()).hexdigest() image_hash = hashlib.sha256(image_data.encode()).hexdigest() verification_data = f"{psbt_hash}:{image_hash}:{additional_context}" return hashlib.sha256(verification_data.encode()).hexdigest() def batch_encode_psbt_collection(self, psbt_list: List[Dict[str, str]], encryption_key: str = None) -> Dict[str, Any]: """ Encode multiple PSBTs for batch processing. """ results = [] key = encryption_key or self.default_key for i, psbt_item in enumerate(psbt_list): psbt_data = psbt_item.get("psbt_data", "") image_data = psbt_item.get("image_data", "") metadata = psbt_item.get("metadata", {}) encoding_result = self.encode_psbt_to_image(psbt_data, image_data, key) result_entry = { "batch_index": i, "metadata": metadata, "encoding_result": encoding_result } results.append(result_entry) successful_encodings = sum(1 for r in results if r["encoding_result"]["success"]) return { "success": True, "batch_size": len(psbt_list), "successful_encodings": successful_encodings, "success_rate": successful_encodings / len(psbt_list) if psbt_list else 0, "results": results, "batch_timestamp": datetime.datetime.now().isoformat() } class PSBTVerification: """ Verification system for steganographically encoded PSBTs. """ def __init__(self, steganography_instance: PSBTSteganography): self.stego = steganography_instance self.verification_log = [] def verify_psbt_commitment(self, script_hash: str, encoded_image: str, encryption_key: str = None) -> Dict[str, Any]: """ Verify PSBT matches script hash commitment. """ try: decode_result = self.stego.decode_psbt_from_image(encoded_image, encryption_key) if not decode_result["success"]: return { "success": False, "error": f"Failed to decode PSBT: {decode_result['error']}", "verification_timestamp": datetime.datetime.now().isoformat() } psbt_data = decode_result["psbt_data"] psbt_hash = decode_result["psbt_hash"] expected_hash = self._extract_hash_from_script(script_hash) verification_status = self._compare_hashes(psbt_hash, expected_hash, script_hash) verification_record = { "script_hash": script_hash, "psbt_hash": psbt_hash, "expected_hash": expected_hash, "verified": verification_status["matches"], "confidence": verification_status["confidence"], "verification_method": "steganographic_psbt", "verification_timestamp": datetime.datetime.now().isoformat(), "decode_result": decode_result } self.verification_log.append(verification_record) return verification_record except Exception as e: return { "success": False, "error": str(e), "verification_timestamp": datetime.datetime.now().isoformat() } def _extract_hash_from_script(self, script_hash: str) -> str: """Extract expected hash from Bitcoin script.""" hash_pattern = r'[a-fA-F0-9]{64}' matches = re.findall(hash_pattern, script_hash) return matches[0] if matches else "" def _compare_hashes(self, psbt_hash: str, expected_hash: str, script: str) -> Dict[str, Any]: """Compare PSBT hash with expected script hash.""" exact_match = psbt_hash == expected_hash if exact_match: return {"matches": True, "confidence": 1.0} partial_match = self._calculate_partial_match(psbt_hash, expected_hash) confidence = partial_match if len(script) > 100: confidence += 0.1 return { "matches": False, "confidence": min(confidence, 0.9), "partial_match_score": partial_match } def _calculate_partial_match(self, hash1: str, hash2: str) -> float: """Calculate partial hash similarity.""" if len(hash1) != len(hash2): return 0.0 matching_chars = sum(1 for a, b in zip(hash1, hash2) if a == b) return matching_chars / len(hash1) def test_psbt_steganography(): """Test PSBT steganography system.""" stego = PSBTSteganography() test_psbt = "psbt_data_example_transaction_with_inputs_outputs" test_image = "PNG_HEADER_IMAGE_DATA_CONTENTS_BINARY_STREAM" encoding_result = stego.encode_psbt_to_image(test_psbt, test_image) print("✅ PSBT Steganography Test:") print(f"Encoding success: {encoding_result['success']}") if encoding_result['success']: decoding_result = stego.decode_psbt_from_image(encoding_result['encoded_image']) print(f"Decoding success: {decoding_result['success']}") if decoding_result['success']: verification = PSBTVerification(stego) script_verification = verification.verify_psbt_commitment( "OP_RETURN OP_HASH160 " + decoding_result['psbt_hash'], encoding_result['encoded_image'] ) print(f"Script verification: {script_verification['verified']}") return encoding_result if __name__ == "__main__": test_psbt_steganography()