This is <i>old</i> cryptography. This book should not be quite as bad for its readers as Schneier&#x27;s Applied Cryptography (which includes many ciphers which were known to be broken at the time, with little hint of that fact in the text), but it&#x27;s still old-fashioned.<p>E.g.<p>- Chapter 7 &quot;block ciphers&quot; doesn&#x27;t even <i>mention</i> CTR mode, but does mention CFB and OFB. Modern cryptosystems all use CTR mode, and no new system I&#x27;m aware of uses CFB or OFB.<p>- Chapter 8 &quot;Public-Key Encryption&quot; doesn&#x27;t even <i>mention</i> elliptic-curve cryptography, despite almost all new cryptosystems being based on that in some form or another. This chapter also doesn&#x27;t appear to mention RSA padding, which is crucial to a secure RSA implementation.<p>- Chapter 9 &quot;Hash Functions and Data Integrity&quot; doesn&#x27;t mention anything newer than SHA-1. But SHA-1 is thoroughly deprecated, and will be broken in the next few years.<p>Just buy a new book instead; I hear good things about Cryptography Engineering, and I liked &quot;An Introduction to Modern Cryptography&quot; (more mathematical, less engineering-focused).