Move signal scripts in folder and add deprecation notice

signal/README.md

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+# Signal
+
+** deprecated - export functionality is removed by now: https://github.com/signalapp/Signal-Desktop/commit/8eeaad8e18823f83fa2c66b82616552b6d2b04e9**

signal/jsonDump.py

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+#!/usr/bin/env python3
+import json
+import sys
+
+content = None
+
+with open(sys.argv[1], 'r') as fh:
+	content = json.load(fh, encoding='utf-8')
+
+print(json.dumps(content, indent=4, separators=(',', ': '), ensure_ascii=False))

signal/signalDesktopDecrypt.py

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+#!/usr/bin/env python3
+import hashlib
+from Crypto.Cipher import AES
+from Crypto.Util import Padding
+from Crypto.Hash import HMAC, SHA256
+import sys
+from getpass import getpass
+from docopt import docopt
+from os import listdir
+
+IV_LENGTH = 16
+NONCE_LENGTH = 16
+MAC_LENGTH = 16
+
+iv = bytearray(IV_LENGTH)
+
+FORMAT_STRING = 'window.Signal.Backup.exportToDirectory(\'{0}\', {{\'key\':new Uint8Array({1})}});'
+
+USAGE_STRING = """
+Usage:
+	signalDesktopDecrypt generate --path <path>
+	signalDesktopDecrypt decrypt --path <path>
+"""
+
+def decrypt(cipherkey, ciphertext):
+	cipher = AES.new(cipherkey, AES.MODE_CBC, iv)
+	return Padding.unpad(cipher.decrypt(ciphertext), AES.block_size)
+
+def generate_cipherkey(key, nonce):
+	h = HMAC.new(key, digestmod=SHA256)
+	h.update(nonce)
+	return h.digest()
+
+def generate_key(password):
+	m = hashlib.sha256()
+	m.update(password)
+	return m.digest()
+
+def extract_info(filepath):
+	data = ''
+	try:
+		with open(filepath, 'rb') as fh:
+			data = fh.read()
+	except FileNotFoundError:
+		print(filepath + ' was not found, please check --path argument')
+		sys.exit(1)
+
+	# extract none
+	nonce = data[:NONCE_LENGTH]
+	# extract ciphertext
+	ciphertext = data[NONCE_LENGTH:-MAC_LENGTH]
+
+	return nonce, ciphertext
+
+def main():
+	params = docopt(USAGE_STRING)
+
+	if params['generate']:
+		# ask for password
+		password = getpass()
+		key = generate_key(password.encode('utf-8'))
+
+		# generate string to be pasted in Signal-Desktop
+		print('Use ctrl+i to open the developer tools in the signal desktop app, switch to console and paste the following text:\n')
+		print(FORMAT_STRING.format(params['<path>'], [elem for elem in key]))
+
+		return
+	elif params['decrypt']:
+		# ask for password
+		password = getpass()
+		key = generate_key(password.encode('utf-8'))
+
+		# extract messages.zip
+		nonce, ciphertext = extract_info(params['<path>'] + '/messages.zip')
+		cipherkey = generate_cipherkey(key, nonce)
+		with open(params['<path>'] + '/messages.zip', 'wb') as fh:
+			fh.write(decrypt(cipherkey, ciphertext))
+
+		# extract attachments
+		for filename in listdir(params['<path>'] + '/attachments/'):
+			nonce, ciphertext = extract_info(params['<path>'] + '/attachments/' +  filename)
+			cipherkey = generate_cipherkey(key, nonce)
+			with open(params['<path>'] + '/attachments/' + filename, 'wb') as fh:
+				fh.write(decrypt(cipherkey, ciphertext))
+
+if __name__ == '__main__':
+	main()