Low level, yes. But, old? We cover AES, HMAC, stream ciphers, GCM, RSA, DH, SRP, and elliptic curves. The criteria for inclusion on the first 6 sets of challenges was "had to be something we took advantage of on the job at Matasano". It's not textbook stuff.
Part of the point of the crypto challenges was to illustrate why people shouldn't work directly with low-level primitives, as a sort of antidote to the kind of advice OWASP gave out.
The first set of problems are all very simple, but you have to start somewhere.
I'm not sure that the cryptopals chalelnges are the best way to learn exactly how you should be implementing everything, but I've found the knowledge that I gained from doing the challenges very applicable in my daily job and definitely helped further my understanding of crypto in a way that reading a book just couldn't do.
Part of the point that I got with cryptopals is how easy it is to break stuff that you thought was hard to break.
There is a theory that we practice on my team that you don't really understand something unless you try to break it. And this team regularly tells developers facts about their programs and systems that previously unknown to them.
Part of the point of the crypto challenges was to illustrate why people shouldn't work directly with low-level primitives, as a sort of antidote to the kind of advice OWASP gave out.