How much can you donate to a candidate without having it show up in the public records?

I want to donate to a political candidate, but I know that my employer and a lot of people where I work believe strongly in the other political party. I don't want someone typing in my name and seeing I donated money to him. Is there a certain amount you can donate that won't show up in the public record? During the 04 campaign I saw a few websites that showed to whom and how much people donated.How much can you donate to a candidate without having it show up in the public records?
In an effort to keep campaign contributions honest and transparent, that information is ALL reported. Would it really affect your standing at work if your employer knew your political beliefs? It's not as if you're holding rallies in the office. Are you sure you want to work in a place that would hold that against you?How much can you donate to a candidate without having it show up in the public records?
What the corporations do is pay someone else to make the donation.