Handling log in and keeping tokens in iOS

I've got a project proposal, and in the spec they want to allow the user to开发者_StackOverflow社区 log in. Thats ok for me, I've done this a few times. On successful login they want a token to be downloaded where on subsequent use of the app in the next 30 days there user will not need to login again due to this token.

Is it safe to store a token on the device like this? Are there many security riskes to doing this? Any any method of handling this that you would recommend?

Many Thanks, Brian

Yes it's save as long as you save the token in the keychain.