How to keep some fields or a content type private I have a content type for concerts, and a view for upcoming concerts. 

For some of the upcoming concerts, the performer (site owner) wants to list just the date and the venue, but cannot list the title of the performance, because the company has not yet announced the season. 

Is there a way to keep part of a node of that content type private, preferable until a specific date has been reached? 

I am looking for a secure and foolproof solution, because I don't want to be subject to a lawsuit, in case the information leaks prematurely. 

The alternative could always be to create two nodes - one of them published with only the public information, with an expiration date, the second one with the full information, initially unpublished, with an automatic publish date. However, I would like to provide a more comfortable way to input the information - add it only one time and don't worry about it. 

So, for the alternative solution - what is the best way to create a node from a node with extracting part of the info of the parent node to the child node? For this scenario, I imagine changing the content type permissions to allow only authenticated users, and creating or updating child nodes in a "public" content type with the allowed subset using something like rules.  

Any hints would be greatly appreciated.
You can do this using Views. Set up a contextual filter for the node id. And then a filter that sets a condition on your date field. This means the View will only have results when (a) your node is displayed and (b) the date condition is matched. Set the filter up as a block. And set that block to show only for that node type.

This is an approach I've used a lot. For example, you can use the same approach to show some fields to logged on users but not to non-logged on users. In effect, you're using the View to show fields depending on some condiiton.