Don't be silly. Of course there are secret govt. contracts.
Some are made public after the contract is completed, some after the contract is started, see the Iraq war and the support contracts, some never see the light of day except as a lump some fequently in another project.
wildfalls it is not that the contract can't be announced; it can. You just can't say what you do for folks like the CIA, if the product has not become a matter of public record, it is prohibited for you to announce the program/product.