In normal usage, I think the word is "traditionalist".
"Paleophile" would be a better word but I don't find it in any dictionary: it's not an accepted word.
- Very late addition and clarification *
If there is no well-known word that expresses an idea you want, you can, of course, always make up a word or use a word that somebody else made up and that only 10 people in the world know. But then you can't expect your readers to know what it means. You'd have to define it. Don't make up a word or use an obscure word with no explanation.
If you would only use this word once or twice, I'd say, in general, don't. Just use a phrase to explain what you mean. If you need to use the word many times so that using the same phrase over and over would be awkward, then sure, invent a new word, define it, and then use it.
Like, "These people are what I will call 'paleophiles', by which I mean, people who love old or ancient things. Paleophiles often ..." etc.
This person would be called private.
"Private" is used to describe not only information, but also people who don't share personal information freely.
There are a variety of expressions to describe someone who does not wish to disclose other types of information, such as "secretive," "tight-lipped," and "discreet." However, "private" seems the best for the situation you've described.
Two other possible candidates are unforthcoming and guarded.
From Oxford Dictionaries online:
private
1.3 (Of a person) choosing not to reveal their thoughts and feelings to others: he was a very private man
unforthcoming
1 (Of a person) not willing to divulge information: the sergeant seemed unforthcoming, so he enquired at the gate
guarded
Cautious and having possible reservations: he has given a guarded welcome to the idea
Best Answer
How about "maven"? According to the Wikipedia article,
[Admittedly, many dictionaries define the word merely as something like "an expert", but the meaning is in flux, and the "person who loves to share knowledge" meaning is getting more common.]