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
Insufficient Key Size

Are you running on all 8 cores? This small key is factorable on a PC with an efficient implementation.

Solved by 118
HÃ¥stad's Broadcast Attack

RSA with a small exponent is fast to compute but it has a serious weakness.

Solved by 104
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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