Is there a book similar to "Cryptography and Network Security" (by Stallings)

I like the book "Cryptography and Network Security - Principles and Practice" by William Stallings because it shows the process flows for varius cryptography protocols. Unfortunately I have not been able to find this book as an ebook. I work in consulting an having books available as ebooks is more convenient.

Are there other books that discuss security protocols in similar detail but which are available as an ebook (preferably as non-DRM PDF)?