Add extra salt

closes #47

config.yaml.example

@@ -5,6 +5,11 @@ bot_token: "BOT_TOKEN_HERE"
 # both take a single argument which is the database file path
 database: [sqlite, "secretlounge.sqlite"]
 
+# salt used for obfuscating user IDs (optional)
+# Needs to be a hexadecimal string, use e.g. `openssl rand -hex 6` to generate.
+# It is recommended to set this. Reusing it between different bots is allowed.
+#secret_salt: ""
+
 # relay contacts
 allow_contacts: false
 # relay arbitrary documents/files (GIFs always work)

secretlounge_ng/core.py

@@ -48,6 +48,9 @@ def init(config: dict, _db, _ch):
 	if config.get("locale"):
 		rp.localization = import_module("..replies_" + config["locale"], __name__).localization
 
+	if config.get("secret_salt"):
+		User.setSalt(bytes.fromhex(config["secret_salt"]))
+
 	# initialize db if empty
 	if db.getSystemConfig() is None:
 		c = SystemConfig()

secretlounge_ng/database.py

@@ -28,6 +28,8 @@ def defaults(self):
 
 class User():
 	__slots__ = USER_PROPS
+	global_salt = b""
+
 	id: int
 	username: Optional[str]
 	realname: str
@@ -43,6 +45,11 @@ class User():
 	hideKarma: bool
 	debugEnabled: bool
 	tripcode: Optional[str]
+
+	@staticmethod
+	def setSalt(salt):
+		assert all(isinstance(v, int) for v in salt)
+		User.global_salt = salt
 	def __init__(self):
 		for k in USER_PROPS:
 			setattr(self, k, None)
@@ -68,7 +75,7 @@ def isBlacklisted(self):
 		return self.rank < 0
 	def getObfuscatedId(self):
 		salt = date.today().toordinal()
-		value = fnv32a([self.id, salt], [])
+		value = fnv32a([self.id, salt], [User.global_salt])
 		# stringify 20 bits
 		return ''.join(ID_ALPHA[n%32] for n in (value, value>>5, value>>10, value>>15))
 	def getObfuscatedKarma(self):