Gmp optional #5
Gmp optional #5
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mpz can now be imported from either gmpy2 or gmpy. Created mpzCast() function, which will behave as an mpz cast only if available. Replaced mpz()s with mpzCast()s in utils.py, except in int_to_mpz. int_to_mpz will return the wrapped function if gmp is not available.
In crypto.py and shamir.py, gmpy2 is no longer explicitely imported, and not needed.
pycryptodome is added as a requirement in setup.py; gmpy2 is kept as a requirement. gen_prime() is kept as a wrapper to getPrime(), but getPrime() is called directly in gen_safe_prime().
If import Crypto... throws ImportError, then fall back to import Cryptodome...
rational: pycryptodome and pycrypto are imported as "Crypto". Installing both at once is a problem. pycryptodomex is equivalent to pycryptodome, exceot it is imported as "Cryptodome". The requirement was switched to pycryptodomex to break computers with pycrypto installed. Despite the requirement list containing only one of the packages, damgard_jurik can use either of the three.
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This article suggests the overhead of a function call with an input variable may be 350ns. test.py calls |
If GMP is not available, try importing Crypto or Cryptodome and use that for prime checking and generating.
In gmp_prime (previously gen_prime), it was possible that the output had a higher length than the requested. Adds check for this. In gen_safe_prime, the outputed number has a more thorough primality check when not using GMP. When using GMP, primality test is thorough by default.
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My first hypothesis turned out to correct:
This is probably due to the computationally expensive Miller-Rabin tests being done without GMP. I reverted |
A previous commit should have the main primality test in gen_safe_prime() set to 15. Added the 15.
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| *Note that the `-e` flag will instruct pip to install the package as "editable". That is, when changes are made to any part of the package during development, those changes will immediately be available system-wide on the activated python environment.* | |||
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| For best performance, [install gmpy2](https://gmpy2.readthedocs.io/en/latest/intro.html#installation). | |||
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@nickboucher Do you think this documentation change is adequate?
Fixes #4
damgård-jurik will take advantage of either
gmpy2orgmpybut doesn't require either. PyCryptodome is used for random prime generation.Explanation
@int_to_mpz@int_to_mpzexisted before this pull request. It takes a function and its inputs as inputs. It goes through each input and casts tompzif appropriate. With this update, ifnot GMP_AVAILABLE, then the given function is returned with out any modifications.mpzCast()Prior to this update, explicit casts to
mpz()existed throughout the source code. With the exception of inside@int_to_mpz, allmpz()s were replaced with the the functionmpzCast()that only casts tompzif possible.I chose a function rather than a type alias, so that if a user inputs a custom integral type, the output will be in that type unless
mpzis available, which takes priority.gen_prime()andgen_safe_prime()[outdated:]In
gen_saf_prime()calls togen_prime()are replaced withCrypto...getPrime()and calls toGmpy2...isPrime()is replaced withCrypto...isPrime().gen_prime()has been kept for backwards compatibility. It is now merely a wrapper forCrypto...getPrime().PyCrypto requirements
There are two similar libraries, PyCrypto and PyCryptodome. PyCryptodome is overall better than PyCrypto, however both of them suit our purposes, and
damgard-jurik/prime_gen.pywill work with either of them. PyCrypto's package name ispycryptoand module name isCrypto. PyCryptodome has two variants, with package namespycryptodomeandpycryptodomex, and the only difference is the module names.pycryptodome's module name isCrypto, andpycryptodomex's name isCryptodome. Sincepycryptodomeandpycryptohave the same name, they will break if installed in the same environment at the same time. Withsetup.pyonly one package name can be specified. Since some users may either already havepycryptoorpycryptodomeinstalled,pycryptodomexis the only package that is guaranteed to not break anything. Ifpycryptodomexis uninstalled after damgard-jurik is installed, then damgard-jurik will keep working as long as eitherpycryptodomeorpycryptois installed.Performance
[outdated:]As of the opening of this pull request,
test.pyruns an order of magnitude slower than in the master branch whether or notgmpy2library is available. Debugging has shown that the library correctly detectsgmpy2and uses it if possible, but the slowing still exists. I have two hypotheses:Crypto.getPrime()doesn't usempz. Cryptodome has an undocumented prime generator that does use mpz for internal use only.mpzCast()calls take longer than a simple cast, and the sheer number of them slow computation down.Neither sound likely, but I don't have any other ideas. Until I figure out how to speed up computation, I will keep this pull request a draft.