How to speed up the generation of prime numbers? What size of primes is needed for RSA?

Question

Python

At the moment, it takes about 4-15 seconds to generate a prime number with 512 digits (I have a fairly powerful machine), but numbers with 1024 digits are required, and so the generation time can be up to several minutes. Requires speed up to 5-10 seconds, with 100% no more than 10 seconds. This code generates prime numbers of a given length:

def isPrime(n, k=20):
  if n == 2 or n == 3:
    return True
  if not n & 1:
    return False

  def check(a, s, d, n):
    x = pow(a, d, n)
    if x == 1:
      return True
    for i in range(s - 1):
      if x == n - 1:
        return True
      x = pow(x, 2, n)
    return x == n - 1

  s = 0
  d = n - 1

  while d % 2 == 0:
    d >>= 1
    s += 1

  for i in range(k):
    a = random.randrange(2, n - 1)
    if not check(a, s, d, n):
      return False
  return True
def genPrime(n):
    	n = n + 1 if n % 2 == 0 else n + 2
    	while not isPrime(n):
    		n += [1,6,5,4,3,2,1,4,3,2,1,2,1,4,3,2,1,2,1,4,3,2,1,6,5,4,3,2,1,2][n % 30]
    	return n
genPrime(random.randint(10**length, 10**(length + 1)))

Where length is the length of the number. How can you speed up the generation of numbers, and does RSA even need prime numbers of this length?

Answer 1

1. Take a normal algorithm
2. Rewrite in Cython

Answer 2

If the goal is to get a number, then

from Crypto.Util import number
number.getPrime(2048)

If the goal is to get a number and write the generation code yourself, then implement this