Use more bytes of seed for gmp_randseed, do not use gmp_randseed_ui because it is always only 32-bits of entropy#5
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…ecause it is always only 32-bits of entropy
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hello!
gmp_randseed_ui takes a 32-bit random number. This means the entropy of the generated modulus/base will be at most 32-bits. An attacker could iterate through all of these seed values in parallel to find the primes that produce a modulus generated by etlp. This takes some time (about three days on 8 cores, according to some experiments I did), but its possible an attacker could create a table of every modulus/base generated by every seed, together with the prime factors, so lookups would be faster
ENTROPY_BYTES = (PRIME_LEN/2)because gen_modulos and gen_gen_base together query the random number generator forPRIME_LEN*4bits. Because ENTROPY_BYTES is in bytes and PRIME_LEN is in bits, we divide by 8 to getPRIME_LEN*4/8=PRIME_LEN/2