Online RSA key generation help


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Public exponent (e) The public exponent (e) is a small integer and is part of the public key.
Valid public exponent values are for example, 3, 5, 7, 17, 257, or 65537.

When creating RSA keys the public exponent is usually 65537 (dec) (= 10001 (hex))

The public exponent (e) requirements are:
  • 1 < e < phi
  • Public exponent e and Euler's phi(n) function are coprime.
Public exponent e and Euler's phi(n) function are said to be coprime if their greatest common divisor is 1, gcd(e,phi) = 1.

Note 1:
Euler's phi(n) function: phi(n) = (p - 1) * (q - 1)

Note 2:
Coprime examples:
  • 6 and 35 are coprime
  • 6 and 27 are not
  • 6 and 12 are not
  • 7 and 11 are coprime
  • 8 and 11 are coprime
  • 9 and 11 are coprime