When it comes to remember me cookies, there are 2 distinct approaches:
Hashes
The remember me cookie stores a string that can iden
Typically you keep the token -> user mapping secure on the server side. So ultimately your security is all based around keeping the token safe and ensuring that its lifetime is controlled (e.g. it expires and/or is only valid when given to you from the same IP as that used by the original provider of the credentials - again, just an example)
Security of token based authentication
Hope this helps.