https://sockpuppet.org/blog/2013/07/22/applied-practical-cry...
It's best to think of Applied Cryptography as an almanac or a work of pop science. The worst thing you can do with it is implement directly from it.
The foreword of the semi-recent (2015) "20th anniversary edition" (which appears to be a reissue of the 2nd edition) even recommends that you look for a more modern reference.
And one of the lessons of the last decades is that programmers should generally not be implementing their own cryptography unless that is their specialty.
> The other two somewhat respected resources at the time were Applied Cryptography and Cryptography Engineering (both from Schneier). But these books were starting to be quite outdated. Applied Cryptography spent 4 chapters on block ciphers, with a whole chapter on cipher modes of operation but none on authenticated encryption. Cryptography Engineering had a single mention of elliptic curve cryptography (in a footnote).