# Tag Info

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Yes, using random.org to randomly select students is appropriate, since random.org creates truly random numbers from atmospheric noise. But for cryptographic purposes you shouldn't rely on random.org as this post explains.

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The entropy will never go higher than the amount you put in. So if you require 128 - 4 = 124 bits and you input 32 bits, you can rest assured that the amount left is at most 32 bits. It's really that simple. And in that case, there is a high likelihood of collisions due to the birthday bound. Now generally you will likely not find dupes during regular use, ...

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good_RNG could be described as: an implementation of an unbiasing (or randomness extraction, or post-processing) algorithm performing the eXclusive-OR of 200 consecutive outputs of bad_RNG, using a loop unrolled by a factor of two, likely with an accidental data-dependent timing dependency beyond that in bad_RNG. This is because when $\mathtt{foo}\in\{0,1\}$...

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The algorithm described is an unbiasing algorithm, which is a type of randomness extraction algorithm. Another method is von Neumann unbiasing where you can take 2 bits $(X_n,X_{n+1})$ and output $Z=0$ if $(X_n,X_{n+1})=(0,1),$ output $Z=1,$ if $(X_n,X_{n+1})=(1,0),$ and discard the two bits otherwise. This gives exactly uniform output bits, if the sequence $... 0 Please ignore this answer, it is a formatting test for this. For$\LaTeX$/MathJax see this.$n=1\$.

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This sounds like a kind of fractionated transposition cipher. My understanding is that some kinds of transposition-alone ciphers can be more difficult to crack than double-Playfair (WGBH 2000), and fractionated transposition ciphers, such as ADFGVX Cipher are considered more difficult to crack than transposition-alone ciphers (Rijmenants). As others have ...

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If you can identify which outputs are revealed and which are thrown off (ex. every other output is thrown off), you may be able to successfully analyze the twister so that you can predict future outputs. However, the bigger problem here is that you are limiting outputs to the range [0,12]. With a 32 or 64 bit word length, a set of numbers in that range will ...

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