Major plot hole: The CIA does not have IVR systems?

I have to say I didn't get the major aspect of the film either. Firstly, all number stations I've ever listened to indeed had automated voices. Okay, that does not necessarily rule out the possible existence of number stations with human announcers doing the broadcasts, but in this case it just seems to come in handy in order to back the plot, because secondly, I do not understand why the CIA (or any intelligence service/number station operator for that matter) would recruit a cryptography expert if all she ever has to do is read out a few numbers? I mean, it was apparently explicitly not part of her job to actually ENcode any messages. Frell, she didn't even know how the principle behind those transmissions works, nor did she know what the broadcasts are for - both are information which is freely available on the Internet, and I guess the first thing someone who lands such a job does is conducting a little Google search which would have revealed so much more background information than she seemed to have. Lastly, if she was such an expert, why the frell would the CIA kill her? Killers can be trained, but maths "geniuses" don't grow on trees.

That said, I did like the pace of the movie, and I was never bored.
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"We're with you all the way, mostly"