Simplify the following text for a Grade 13 native English-speaking person.
Original: Masquerading is the mechanism that hides an entire address space , usually consisting of private network addresses ( RFC 1918 ) , behind a single IP address usually in the public domain address space .
Simplified: However it is common to hide an entire IP address space , usually consisting of private IP addresses , behind a single IP address ( or in some cases a small group of IP addresses ) in another ( usually public ) address space .