Function oath::ocra

pub fn ocra(
    suite: &str, 
    key: &[u8], 
    counter: u64, 
    question: &str, 
    password: &[u8], 
    session_info: &[u8], 
    num_of_time_steps: u64
) -> Result<u64, ()>

ocra is a wrapper over ocra_debug function. Use this function in production code! ocra function doesn't leak any info about internal errors, because such internal info could be a starting point for hackers.