About

Below are some problems related to computer security (specifically poorly implemented security). Do Them. You are free to use any language and environment you like to complete them. The problems require familiarity with programming, but not necessarily with applied cryptography or computer security in general. An understanding of how some of the algorithms and tools in the problems work will be of use, so as a starting point you can find some resources to help you begin here. If this topic is new to you, you may want to start with the Tutorial Problems.

Problems

Forging OCB2 Mode Tags

OCB2 mode is proven to be theoretically secure. Unfortunately it's not practically secure.

Solved by 20
RSA Modulus Factorization

Factor an RSA modulus using the public and private key

Solved by 90
DSA with LCG nonces

Even we don't know how to solve this one

Solved by 19
Recover the secret phone number

Call it if you want, I don't care, it's not mine

Solved by 55
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