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Comment by AnotherGoodName

2 days ago

Another similar one is that we don't care for strong primes anymore and even though the standards for RSA specifically require it, it's not actually helpful at all, see https://eprint.iacr.org/2001/007

Strong primes are ones where the totient (both carmichael and euler totients) have large primes in them. This happens naturally for 2048 bit and above RSA keys in any-case, they'll statistically absolutely have primes that are larger than the bits needed to factor using elliptic curve methods (>256 bits). In general it's just not that helpful, similar to trying to require carmichael rather than Euler totient. Ok you've made the 2048 bit key 3 bits stronger, great, but let's not bother right?

Do the standards require strong primes for RSA? I think FIPS doesn't ... it gives you that option, either for the legacy reasons or to get a proof with Pocklington's theorem that (p,q) really are prime, but just choosing a random (p,q) and running enough rounds of Miller-Rabin on them is considered acceptable IIRC.