As someone says, one-time pads are impossible to decrypt without they key. But you can guess the key or use some other brute force mechanism.
Actually, you can't even reliably brute force a one time pad. The key is always the same length as the message. All plausible messages of length N are equally valid solutions for a brute forcing algorithm.
You could be using a One Time Pad for key management. This is certainly feasible now, since a couple of Gigabytes of data is now considered a manageable amount.
My guess, SHA-256 will fall to a quantum computing algo in a few years.