The details of how cryptographic algorithms are designed, implemented, verified, and assembled into cryptosystems requires expert knowledge. Fortunately, the big picture of how the resulting cryptosystems are used does not. For most users and even most programmers, the underlying algorithms are black boxes that they do not and need not understand, while the language and conceptual framework of modern cryptography are very useful in putting those algorithms to practical use.
We will sketch out that conceptual framework at action-movie speed using the simplest of classical cryptographic algorithms to represent the modern black boxes for concreteness while studing everything but the algorithms themselves. After the presentation you should understand: elementary cryptographic language, security as a probabalistic rather than absolute guarantee, why the size of the keyspace matters, why practical security depends on choosing keys randomly, what side-channel attacks are, what public-key cryptography is, and what a digital signature is. You should also have the basic conceptual framework and vocabulary for further study or self-study. The presentation should be accessible to beginners of all ages. A laptop will be useful but not necessary.