A nitpick: When discussing hash function properties (p. 111), his definition of property #1 ("[it should be hard to] modify a message without changing the hash") is, to me, equivalent to second-preimage resistance ("[Given] a message m, it should be difficult to find another message m' with the same hash"), which he discusses as a separate property under prop #3.

In the explanation of prop #1, he makes it clear that he is talking about the "avalanche effect," so it might be better to say that explicitly in the definition.

Disclaimer: I'm not a crypto person, so it's better if the author comments on this as well.

I think the book is great, by the way, especially the writing style and the choice of what to focus on. Thanks, lvh, for doing this.