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da3bc3d927
I've replaced the random number generation and small delta-finding loop in primegen() with a much more elaborate system in its own source file, with unit tests and everything. Immediate benefits: - fixes a theoretical possibility of overflowing the target number of bits, if the random number was so close to the top of the range that the addition of delta * factor pushed it over. However, this only happened with negligible probability. - fixes a directional bias in delta-finding. The previous code incremented the number repeatedly until it found a value coprime to all the right things, which meant that a prime preceded by a particularly long sequence of numbers with tiny factors was more likely to be chosen. Now we select candidate delta values at random, that bias should be eliminated. - changes the semantics of the outermost primegen() function to make them easier to use, because now the caller specifies the 'bits' and 'firstbits' values for the actual returned prime, rather than having to account for the factor you're multiplying it by in DSA. DSA client code is correspondingly adjusted. Future benefits: - having the candidate generation in a separate function makes it easy to reuse in alternative prime generation strategies - the available constraints support applications such as Maurer's algorithm for generating provable primes, or strong primes for RSA in which both p-1 and p+1 have a large factor. So those become things we could experiment with in future. |
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| .. | ||
| sclog | ||
| agenttest.py | ||
| agenttestdata.py | ||
| agenttestgen.py | ||
| colours.txt | ||
| cryptsuite.py | ||
| desref.py | ||
| display.txt | ||
| eccref.py | ||
| lattrs.txt | ||
| scocols.txt | ||
| ssh.py | ||
| testcrypt.py | ||
| utf8.txt | ||
| vt100.txt | ||