cryptanalysis | 易学教程

How to implement modular exponentiation?

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问题 I am trying to calculate something like this: a^b mod c, where all three numbers are large. Things I've tried: Python's pow() function is taking hours and has yet to produce a result. (if someone could tell me how it's implemented that would be very helpful!) A right-to-left binary method that I implemented, with O(log e) time, would take about 30~40 hours (don't wanna wait that long). Various recursion methods are producing segmentation faults (after I changed the recursion limits) Any

How can I write vigenere cryptanalysis of persian text?

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问题 How can I write Vigenere cryptanalysis for persian language? Is there any sample source code for persian? 回答1: I was unable to find a Persian-language version of Vignere cryptanalysis. You could try one of the solutions here and adapt the alphabet used to the persian alphabet. (You'll need persian-language letter usage statistics, it won't work with english ones.) I recommend the python but that's just personal taste. 来源： https://stackoverflow.com/questions/34795192/how-can-i-write-vigenere

How to predict the next GUID from a given GUID?

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I have sent 10000 mails to our customers and each mail had a link of the format http://example.com/LogIn?key={guid} Unfortunately the guid I sent were random guids (test data generated by Guid.NewGuid() ) so the customers have all received invalid links... Based on the 404s i receive from the webserver I have a few guids that I sent out. I have read that the guid generator in windows is weak so you can predict the next guid from one you already have. Does anyone know how? If i could do that I could make the guids I sent out valid so the links would work again. Will Dean The way Windows has

How to predict the next GUID from a given GUID?

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问题 I have sent 10000 mails to our customers and each mail had a link of the format http://example.com/LogIn?key={guid} Unfortunately the guid I sent were random guids (test data generated by Guid.NewGuid() ) so the customers have all received invalid links... Based on the 404s i receive from the webserver I have a few guids that I sent out. I have read that the guid generator in windows is weak so you can predict the next guid from one you already have. Does anyone know how? If i could do that I