79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798,483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8 seems very random to me. I see how this point is on the curve, but how exactly was this specific point chosen to be the base point? Could other base points have worked?


Since the secp256k1 curve order is prime, every point on the curve except the point at infinity is a generator.

Nothing is known about how the designers of the curve chose this specific generator.

However, there is one tell-tale sign that hints about its construction. When the chosen generator G is multiplied by 1/2 (i.e. multiplied by the multiplicative inverse of 2 modulo the curve order), the resulting X coordinate is an exceptionally low number. This very likely means that G was created by picking that X, finding a corresponding Y on the curve, and then doubling the resulting point.

  • Can you share this low number X?
    – k06a
    Jan 23 '18 at 9:12
  • 1
    G/2 = (0x3b78ce563f89a0ed9414f5aa28ad0d96d6795f9c63, 0xc0c686408d517dfd67c2367651380d00d126e4229631fd03f8ff35eef1a61e3c). Jan 23 '18 at 15:01
  • Is there a reason why it needs to be random and large like this? It seems like y^2=x^3+7 is a nice "nothing up my sleeve" curve, but I can't say the same about this base point. Is security compromised in any way if the X coordinate of the base point was chosen to be a tiny number like 3 or 7?
    – lurf jurv
    Jan 28 '19 at 19:48
  • 1
    @lurfjurv To the best of my knowledge, the choice of the generator is not relevant to the security of ECDSA. Jan 28 '19 at 19:55
  • 2
    I see, so the choice is irrelevant. Is this not suspicious then? Why not pick a trivially small number for x to remove any concern that this base point has some fatal flaw or backdoor?
    – lurf jurv
    Jan 29 '19 at 21:28

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