Cryptography: An Introduction (2011) [pdf]

[Tomte]

http://www.cs.umd.edu/~waa/414-F11/IntroToCrypto.pdf

[brightball]

If you just want to get somebody interested in cyptography, I HIGHLY recommend: The Code Book (http://amzn.com/0385495323). It's a great read for anybody who's done a little bit of history by walking you through the role of cryptography and hiding messages throughout history.

Covers most everything in the context of war history as far back and shaving a person's head, writing a message on it and then letting the hair grow back to hide it. Great read that will lay the groundwork of interest for a lot of people.

[jgrahamc]

This has a really nice section on work done by Jerzy Różycki, Henryk Zygalski and Marian Rejewski on the cryptanalysis of Enigma.

[davidw]

This is a great book, I based our company's own proprietary crypto code on what I picked up while skimming through it. Kidding...kidding!

[tptacek → davidw]

You are the worst.

[springogeek]

We used this book as the source material for the cryptography course I took in the final year of my degree.

I can confirm that the content is very approachable. It even provides a great section introducing some of the core mathematics required.

[mrcactu5]

here is a very theoretical account by Luca Trevisan of Stanford

http://theory.stanford.edu/~trevisan/books/crypto.pdf

[cjlm]

Excellent introduction from an excellent academic.

[helicon]

I'm currently working through Cryptography 1 on Coursera and struggling with some of the maths involved, so hopefully this will help.

https://www.coursera.org/learn/crypto

[nanocyber]

I don't see a finalization/publication date in the text... can anyone provide and source?

[bedros]

this is a gem. it's hard to find all that info in one place.