If you enjoy these challenges you might want to join my team at Google, to analyze, break, design and implement real-world crypto solutions for products used by billions of people.
Aside from short-term projects like analyzing and improving state-of-the-art password hashing or end-to-end encryption schemes, we've started two long-term that could use your help: Wycheproof [1] and Tink [2]. The former is a revolutionary testing framework that has discovered 40+ bugs [1] in many popular crypto libraries. The later provides a safe, simple, agile and fast way to accomplish common crypto tasks.
If this sounds exciting, please send your resumes to thaidn@google.com. Cheers!
[1] https://github.com/google/wycheproof
[2] https://github.com/google/tink
[3] https://github.com/google/wycheproof/blob/master/doc/bugs.md
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