What is Reddit's opinion of Cryptography: Theory and Practice, Third Edition (Discrete Mathematics and Its Applications)?
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As you say: Having an M.Sc in Crypto may provide a good foundation, but what, if any, specialist qualification or knowledge it provides is questionable.

The biggest personal milestones have been reading Stinson's work, and being able to understand and synthesize results on my own within that body of work. For example, with FHE, being able to port some of the claims into CUDA.

That said, it'd be interesting if there were ways to attest to the knowledge and practice of individuals on the subject. Right now it seems almost purely reputation based.

As a math undergrad, I highly recommend this book. You should have a strong foundation in both Group Theory and Number Theory and some decent programming skills before you dive into it but it approaches the topic from a very sensible and mathematical way.