Zeroize KeyObfuscator keys on Drop

.. to make sure the values don't linger in memory.

Author: tnull

src/util/key_obfuscator.rs

@@ -151,6 +151,14 @@ impl KeyObfuscator {
 	}
 }
 
+impl Drop for KeyObfuscator {
+	fn drop(&mut self) {
+		// Zeroize the owned keys
+		self.obfuscation_key.copy_from_slice(&[0u8]);
+		self.hashing_key.copy_from_slice(&[0u8]);
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use crate::util::key_obfuscator::KeyObfuscator;